Intermaxillary Fixation Techniques
An EACMFS workbook on keying occlusion and restoring bony anatomy by intermaxillary fixation techniques
Editors
José M. López‐Arcas, MD, DDS, PhD
Julio Acero, MD, DMD, PhD, FEBOMFS
Maurice Y. Mommaerts, MD, DMD, PhD, FEBOMFS
Bruges, 2010
Table of Contents
Preface I ...............................................................................................................................................4
Preface II..............................................................................................................................................5
1. Introduction...................................................................................................................................6
2. A history of the management of maxillofacial injuries. The development of intermaxillary fixation. ..................................................................................................................7
3. Material properties .................................................................................................................. 12 3.1. Basic material properties ........................................................................................................12 3.2. Arch wire properties...............................................................................................................14
3.2.1. Precious metal alloys............................................................................................................... 14 3.3. Bands .....................................................................................................................................15
4. Protection from prick accidents .......................................................................................... 17
5. Dental trauma ............................................................................................................................ 20 5.1. Acid‐etch resin arch wire splint...............................................................................................20 5.2. Orthodontic bracket arch wire splint ......................................................................................22
6. IMF techniques........................................................................................................................... 24 6.1. Ligature wiring........................................................................................................................24
6.1.1. Gilmer wiring........................................................................................................................... 25 6.1.2. Kazanjian button ..................................................................................................................... 26 6.1.3. Eyelet technique...................................................................................................................... 27 6.1.4. Intermaxillary loop wiring (Stout) ........................................................................................... 33 6.1.5. Cable arch wire (Fig. 21) ......................................................................................................... 34 6.1.6. Multiple loop wiring (Obwegeser method) ............................................................................. 35 6.1.7. Leonard’s button wiring (Fig. 25) ............................................................................................ 37 6.1.8. Banded retention appliance.................................................................................................... 38
6.2. Arch bar techniques................................................................................................................39 6.2.1. Groningen‐type custom‐made arch bar.................................................................................. 40 6.2.2. Erich arch bar .......................................................................................................................... 43 6.2.3. Schuchardt’s wire, acrylic arch bar ......................................................................................... 48 6.2.4. Dautrey arch bar ..................................................................................................................... 51 6.2.5. Bern’s titanium arch bar ......................................................................................................... 52 6.2.6. Baurmash’s arch bar ............................................................................................................... 54
6.3. Cap splints ..............................................................................................................................55 6.3.1. Cast acrylic spints with cusps of the teeth exposed ................................................................ 56 6.3.2. Cast silver cap splints .............................................................................................................. 57
6.4. Gunning‐type splints...............................................................................................................61
7. IMF screws................................................................................................................................... 65
8. IMF techniques in children.................................................................................................... 70 8.1. Houpert’s procedure...............................................................................................................70
9. Wire suspension techniques................................................................................................. 72 9.1. Circummandibular wiring .......................................................................................................72
9.1.1. Black‐Ivy procedure................................................................................................................. 72 9.1.2. T. Paoli procedure (transalveolar wiring)................................................................................ 74
9.2. Pyriform aperture suspension.................................................................................................74 9.3. Nasal spine suspension (Ombredanne‐Broadbent) .................................................................75 9.4. Inferior orbital rim suspension................................................................................................76 9.5. Circumzygomatic suspension (Rowe ‐ Obwegeser)..................................................................77 9.6. Supraorbital rim suspension ...................................................................................................79 9.7. Kufner suspension ..................................................................................................................80
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10. ORTHODONTIC AUXILIARY APPLIANCES FOR IMF IN ORTHOGNATHIC SURGERY........................................................................................................................................... 81 10.1. Teeth and bracket types .......................................................................................................81
10.1.1. Bracket with hook (Fig. 72) ................................................................................................... 81 10.1.2. Power Pins (arms) (Fig. 73F and G) ....................................................................................... 82 10.2.3. Buttons .................................................................................................................................. 82
10.2. Tie or ligature appliances......................................................................................................85 10.3. Arch wire appliances.............................................................................................................86
10.3.1 Soldered brass hook ............................................................................................................... 86 10.3.2. Pre‐posted arch wires ........................................................................................................... 87 10.3.3. Crimpable hooks.................................................................................................................... 87
Acknowledgments......................................................................................................................... 90
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Preface I
The idea for this workbook originated in 2007 when Dr. López‐Arcas was an EACMFS fellow in Bruges. He requested to work on a large‐scale “European project.” I had noticed that surgeons‐in‐training acquire skills in their particular training center and remain oblivious to less fashionable, “old” techniques or techniques used at other centers. For example, in the 1980s, the Zurich school exclusively used Obwegeser wire‐loop splints, while the Basel school exclusively applied Schuchardt acrylic wire splints. Personally, I learned about the usefulness of silver cap splints with guiding wings after condylar resections, but did not use them for 20 years until a patient presented with bilateral joint ankylosis due to a 3‐month intubation for burns after a gas explosion. The only way to control occlusion was by using the “old” technique. Suspension wires have fallen out of favor in an era of open reduction and plate osteosynthesis, and indeed the dish‐faces with mandibular over‐rotation and post‐traumatic retromaxillism, telecanthus, enophtalmia, and nasal dorsum flattening have disappeared. Still, I found pyriform and zygomatic suspension wires very useful in a case of subtotal resection of a juvenile ossifying fibroma in a 3‐year‐old girl to suspend an intraoperatively made prosthesis to support the pack. Hence, I presented my proposal to organize the John Lowry Education Course at the EACMFS 2010 Congress with “intermaxillary fixation techniques” as the main topic. A permanent record, in the form of this workbook, was produced by Dr. López‐Arcas and his friend Dr. José Mª Garcia‐Rielo to whom I am very grateful. Mr. John Williams wrote the chapter on history.
Special thanks also go to the maxillofacial labs of “Dentaal Tema en Rongé” of Brugge, “Labo Degraeve” in Roeselare, and to Hans Hager of the University of Zurich for descriptions and iconographies of special techniques.
Prof. Julio Acero supervised the project and persuaded course conductors to participate, for which he deserves much gratitude.
I hope the techniques described may be useful in your practice!
Maurice Mommaerts MD DMD PhD FEBOMFS
President EACMFS 2008‐2010
President EACMFS XXth Congress
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Preface II
As the EACMFS Education and Training Officer, it is a great honour to endorse this manual on intermaxillary Fixation Techniques. In the past wire‐fixation techniques played a major role in the treatment of facial deformities and cranio‐maxillo‐facial trauma and was a cornerstone of our specialty. Trainee surgeons are nowadays less exposed to these methods since maxillo‐facial trauma management has evolved over the past decades with to the introduction of new techniques such as rigid or semi‐rigid internal fixation. The purpose of this handbook is to review the IMF techniques currently available as well as the classic wiring techniques aiming to provide young specialists and trainees with the knowledge of classic fixation techniques, which can be helpful in different situations.
This manual opens with a review of the history of the management of maxillo‐facial injuries and then covers the fundamentals of IMF and wire fixation techniques, including concepts on materials properties, armamentarium, methods, advantages and drawbacks. A short reference to the indications of these techniques in children is made. The final chapter provides detailed review of the use of orthodontic appliances for intermaxillary fixation.
I gratefully thank the authors for their effort in preparing this comprehensive manual which I am certain that will be an useful reference for specialists and residents in oral and cranio‐maxillo‐facial surgery. Very special thanks go to Maurice Mommaerts, EACMFS President, and José Mª Lopez‐Arcas for their enthusiastic input and incredible work, which made possible this book.
Julio Acero MD DMD PhD FDSRCS FEBOMFS
EACMFS Education and Training Officer
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1. Introduction
Many of the conventional arch bars or wiring techniques were developed at a time when most facial fractures were treated by intermaxillary fixation (IMF) only and therefore had to be sufficiently stable to maintain immobilisation for a prolonged period. Since the introduction of open reduction and rigid osteosynthesis (ORIF) protocols, IMF has been predominantly used to obtain normocclusion during the surgical procedure or for a short period postoperatively for support using rubber bands. In some cases, IMF bone screws may be sufficient. Consequently, the indications for using simpler IMF systems are increasing.
There are still situations in cranio‐maxillofacial (CMF) trauma in which stable IMF using conventional arch bars with circumdental wire fixation is necessary. These conditions include nonoperative treatment of displaced condylar fractures and final occlusal adjustment using guiding elastics after open reduction internal fixation (ORIF) for comminuted mandibular fractures and displaced fractures of the maxilla.
Other situations include partially edentulous jaws where it is difficult to find a proper relationship between the dental arches when treating a complex fracture and in certain cases of bony reconstruction following tumour resection. In these situations, IMF using bone screws or arch bar fixation using direct bonding techniques tends to be unstable or even impossible to carry out because of the lack of teeth and occlusion.
The purpose of this manual is to show the surgeon‐in‐training the IMF techniques that are currently available as well as the classic wiring techniques that can be helpful in certain circumstances.
Dr. José M. López‐Arcas Dr. José Mª Garcia‐Rielo
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2. A history of the management of maxillofacial injuries. The development of intermaxillary fixation.
Although trauma has been with us since the dawn of time, it is only recently that we have been able to approach it scientifically. For this reason, the original reports of treatment do not necessarily follow any logical pattern, amounting to a series of case reports contained within the literature from the earliest pre‐Christian times to Egypt in 2000 B.C. when a dislocation of the mandible as well as a fractured mandible were described. Hippocrates described reduction and fixation of mandibular fractures with strips of calico glued to the skin immediately adjacent to the fracture and laced together over the scalp. The ancient physicians of Alexandria and Rome also mentioned the ligation of teeth using fine gold wire or Carthugian leather strips glued to the skin. These principles laid down by Hippocrates extended through the literature as far as the first millennium.
It was probably Salicetti in 1474 in Bologna who first described the simple expedient of ligating the teeth of the lower jaw to the corresponding teeth of the upper jaw to affect immobilisation of a fracture. Previously, it was recognised that within 3 weeks, the union of jaw fractures would be complete.
The 16th and 17th centuries saw the introduction of gunpowder and the first reports of gunshot wounds. It was Ambroise Paré to whom we must attribute the first significant change in the management of facial wounds via copious irrigation and the application of balms rather than the use of cauterisation. His particular care of facial wounds and his application of what he described as “a dry suture” facilitated secondary healing of these wounds, particularly treatment of compound wounds.
The next milestone was achieved by Richard Wiseman, a surgeon in the latter part of the 17th century, who described the management of maxillo‐facial injuries. As well as describing the signs and symptoms of a fracture, he also described many individual cases, including a child with a comminuted fracture of the cribriform process of the ethmoid. He also described the disturbance in occlusion and related protrusion or recession of the lower jaw and the destruction of soft tissues in association with these injuries. These astute clinical observations were added to those studies of anatomy and physiology at the Italian schools of Bologna and Padua in the early 18th century. Together, they laid the foundation for serious advances in the systematic management of jaw injuries.
Chopont & Desault (1780) were the first to describe a different type of approach by introducing the concept of a dental splint that consisted of a shallow trough of iron, inverted over the occlusal surface of the lower teeth, which were protected with cork on lead plates. A bar projected from the front incisor region, bent at right angles, and fastened by thumbscrews to a submandibular plate of sheet iron. Movement of the fragments was thus prevented by compression between the occlusal surfaces of the teeth and the lower border of the mandible.
Variations of this principle were employed during the next 100 years and were introduced subsequently into Germany by Rutenik in 1799, who further stabilised the head harness, into England by Lonsdale in 1833, and into Holland by Hartigs & Grebber (1840); however, each was a modification of the original principle that still found employment after World War II for the fixation of certain
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epithelial inlay splints in the edentulous mandible. Different forms of supportive bandaging were introduced, accompanied by wedges of cork between the occlusal surfaces of the teeth to keep the teeth apart and facilitate feeding. Earlier in 1825, Naysmith co‐operated with Robert Liston to provide a cast, gold cap splint. This splint was soldered together and affixed to the teeth to prevent the displacement of the mandible in a mandibulectomy case until the majority of the forces of soft tissue contraction had dissipated.
The discovery of anaesthesia allowed for a significant advance when Fauchard in France and Buck in the USA began to use direct intraosseous silver wires. Results were variable due to the development of sepsis and consequent sequestration. A variation by Wheelhouse involved driving silver pins through each piece of bone and winding silk thread around each pin in a “figure eight” to approximate the bone ends.
War has always provided opportunities for surgical developments, and so it was with the American Civil War of 1861‐1865 and the Franco‐Prussian War of 1870‐1871, in quick succession, that a large proportion of mandibular fractures arose from horse kicks or falls onto the chin. In 1861, Gunning produced his splint, although he was probably unaware that it followed the same principle as the one developed by Naysmith in 1825 for use by the surgeon Liston. From dental impressions, a monobloc construction was produced and bound to the jaws by a bandage that passed under the chin and over the vertex of the skull. Teeth in the line of fracture were extracted. Later in the war (1864), Bean, who treated many fractures, made a significant advance by sectioning dental models of the jaws and carefully realigning them before constructing a Gunning type of splint.
The first reports of swaged metal splints appeared simultaneously by Allport in America and Hayward in London. Allport’s gold splints were swaged to leave the occlusal and incisive edges free, and, having correctly aligned them, the splints were soldered together. Soft gutta‐percha was used to attach the splints to the teeth. Hayward covered the occlusal surfaces of the teeth and used soft gutta‐percha for attachment. A separate submental gutta‐percha splint was placed in position and a bandage or rubber band was used to connect it to two arms projecting from the splint and curving backward around the commissures of the mouth. Despite further modifications by Kingsley, all these splints were essentially modifications of the original splint by Chopart and Desault in 1780.
The inherent weakness in all these splints was the lack of secure fixation to the jaws, and various attempts were made to overcome this problem. Initial descriptions by Hamilton Adams in 1871 used fine nuts and bolts that passed through the interdental spaces. Some 3 years later, Moon, in London used fine interdental wires to achieve the same result. It was at about this same time, that Woodward, in the USA, melted down silver coins (silver and copper) to produce opencast, metal cap splints, attached to the crowns of the teeth by small screws. The two splints were connected to one another by lugs, and through the means of eyelets soldered to them, the jaws could be wired together, thus giving IMF. Although a significant advance, the very complicated nature of the process and the lack of a cementing medium for attaching the splints to the teeth meant that these splints did not catch on rapidly. However, attention is now shifting to the improved accuracy of reduction provided by focusing on the occlusion.
During the Franco‐Prussian War, Hammond described the use of arch bars on both the lingual and buccal aspects that were fixed to the teeth by fine interdental eyelet wires. This process was adapted for both the wiring of the arch bars and the continuous loop method. At the same time, Suerson, in Berlin, who had been chiefly employing the Gunning principles, but when treating malunions, conceived of using separate splints for each section and of driving wedges of hickory wood of ever‐increasing thicknesses between these splints, which gradually realigned the arches. This seems to be the first account of an attempt to realign the displaced arches.
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In 1887, Gilmer returned to an almost forgotten technique, the direct wiring of teeth. This resurrection of an old principle, suitably modified, was a significant advance and became increasingly important as orthodontic techniques became adapted by surgeons for the treatment of fractures. Angle applied his principles of fixed anchorage points and individual bands cemented to selected teeth in each jaw as a means to restore a correctly aligned dentition. So now, for the first time, we see science applied to the management of these injuries. This, together with the huge advances in surgery occasioned by the introduction of anesthesia, the institution of antiseptic and later aseptic techniques, and the introduction of X‐rays for clinical purposes by Roentgen in 1895, changed the scene dramatically. Other significant advances that followed at that time include the reconstructive work of Abbé, Estlander, and Thiersch; the first treatment of fractured zygomas by Matas (1896) and the midface by Bouvet in 1901; Le Fort’s work on fracture patterns; and the surgical approaches to the zygoma of Lothrop (1906), Keen (1909), and Manwaring (1913), which led up to the casualties of the 1914‐1918 war in Europe.
The scale of these injuries, 26 million casualties of the 56 million individuals involved in armed conflict, was due largely to trench warfare and the destructive nature of high‐energy explosives that rendered the face prone to more severe injury than had been seen previously. However, the sound principles laid down at the turn of the century did not undergo any radical changes; rather, there were a series of refinements in techniques that often followed the application of orthodontic principles to splint construction. Circumferential wires were used in some cases, Gunning‐type splints were used in others (especially edentulous cases), and both open‐ and closed‐cast silver cap splints in dentate patients were used to a greater extent than had been used previously. Fresh cases were treated by sectioning the models, restoring the occlusion in the laboratory, and forcing the segments into the splints at the time of reduction and immobilisation. In cases where treatment was delayed, reduction was achieved using orthodontic techniques. The use of interdental eyelet wires was demonstrated by Ivy (1914) as an effective way to provide IMF in the dentate patient and was increasingly practised.
Replacement of both hard and soft tissues had reached a remarkable degree of sophistication with surgeons developing ingenious techniques to achieve outstanding results, but sepsis, leading to gangrene, hospital‐based infections, as well as other general infections, all contributed to the high level of morbidity and mortality of that time. Lister, followed by the first chemotherapeutic agent, prontosil, made great strides to treat these severe complications. There followed certain, specific improvements in the surgical care of facial fractures. Notable among these was the development at East Grinstead of sectional splints, one for each segment, linked together by intraorally located, locking plates, which underwent later modification to be located extraorally. Middle third fracture management also underwent improvements where cheek wires, first developed by Federspiel, were used to fix the posterior region of the maxilla to the plaster of‐Paris headcap.
By the end of World War II in 1945, there was an increasing realisation that when bone ends are brought into close proximity with one another, more rapid healing occurs. With the advent of antibiotics, a greater use of direct approaches to the fracture sites led to the use of direct interosseous bone wiring or osteosynthesis. Such wires were generally applied to either the upper or the lower borders of the mandible and the fronto‐zygomatic suture, all solid pieces of bone. During this time, pin fixation was used, particularly in the treatment of compound, comminuted, and frequently infected jaw fractures. Despite a reduction in its use, this concept was retained and used by Fordyce in the “Box‐Frame” technique. A variety of pins were used from the fine, threaded, Clouston‐Walker pin, modified for the East Grinstead pattern, and MacGregor pins, to the coarse, threaded, tapered, Moule pin. It was not until the Vietnam War that American forces came to use
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biphasic pin fixation, popularised by Morris (1949), and external pin fixation again became the treatment method of choice.
With the advent of the antibiotic era, recognition of the value of direct fixation became widely accepted in orthopaedic practice and was adapted for maxillo‐facial purposes. Initially, direct bone wiring was used to control 1) the edentulous posterior fragment; 2) multiple fragments in the edentulous mandible; and 3) the grossly comminuted mandibular fragments and the lower border of the mandible where the upper jaw was already secured by one of the conventional methods of fixation but where the lower border remained inadequately reduced and immobilised.
Although the use of bone plates had previously been attempted (Konig, 1905; Lambotte, 1907; Lane, 1914; Sherman, 1924), it was not until Roberts (1964) and Battersby (1967) introduced stainless steel, vitallium monocortical miniplates that the present use of surgery was established. The lack of malleability of these initial miniplates limited their usefulness for they broke as soon as any attempt was made to bend them. The initial introduction of malleable stainless steel followed by titanium enabled Champy (1976, 1978) to develop a scientific basis for the application of miniplates in the treatment of mandibular fractures. Inevitably, numerous clinicians and manufacturers provided their own modifications, but the principles of application remain unchanged.
Bioresorbable plates, made initially of polylactic acid and, more recently, of a combination of this and other suitable materials, were developed (Bos, 1983; Rozema, 1991; Suuronen, 1992). Their biodegradation tends to be accompanied by a significant collection of fluid beneath the skin.
The compression osteosynthesis techniques used by orthopaedic surgeons have been applied to maxillo‐facial surgery by Luhr (1968, 1972) and Becker & Machtens (1970). The use of specially designed taps and matching screws allowed both cortices to be engaged that, when combined with the specially designed plates, produced firm opposition of the fractured bone ends under compression. This process results in primary bone healing by direct osteoblastic activity within the fracture as opposed to secondary bone healing through callus formation.
Intramedullary pinning and the use of titanium as well as nonmetallic mesh, particularly in the treatment of malunions and fractures of the edentulous mandible, all have important applications.
REFERENCES
• Adams F. The Genuine Works of Hippocrates. London, Sydenham Society, 1849. • Adams WM. Surgery, 12:523, 1942. • Casserius J. Tabulae Anatomicae‐de vocis auditusque organis historia anatomica. Ferrara, 1600. • Salicerri G. Praxeos Totius Medicinae, De Chirurgia, Venice, 1275. • Tagliacozzi G. De Curtorum Chirurgia per Institionem. Venice, 1597. • Oliver RT. JAMA 54:1187, 1910. • Paré A. The Workes of the Famous Chirurgion Ambroise Parey. Translated out of the Latine and compared with
the French. Johnson, T. London, Cotes and Young, 1634. • Wiseman R. Several Chirurgical Treatises. London, 1686. • Rutenick FG. Dis. de fractura mandibulae, Berol, 1823. • Hartig FR, Greeber H. Beschriving van een nieuw toestel voor de breuk van de onderkaak. Amsterdam, 1840. • Gunning TB. New York Med J 3: 433, 1866. • Gunning TB. New York Med J 4: 514, 1867 • Fauchard P. Traité de Chirurgie Dentaire. Paris, Mariette, 1728. • Chopart E, Desault PJ. Traité des Maladies Chirurgicales. Paris, 1779. • Matas R. New Or Med Surg J 49:139, 1896. • Gilmer TL. Fractures of the Inferior Maxilla. J Dent Sc 1:309, 1881. • Le Fort R. Rev de Chir 1: 208‐260,1901. • Gilmer TL. Arch Dent 4: 388, 1887. • Ivy RH. Surg, Gynaec and Obst 52:849, 1922. • Eby JD. J Nat Dent A 7:771, 1920. • Gillies HD, Kilner TP, Stone D. Brit J Surg 14:651, 1927.
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• McIndoe AH. Proc R Soc Med 34:267, 1941. • Macintosh RB, Obwegeser H. Internal wiring fixation. Oral Surg, Oral Med, Oral Path 23:703, 1967. • Roberts WR. Brit J Oral Surg 1:200, 1964. • Rowe NL, Killey, HC. Fractures of the Facial Skeleton. Edinburgh, E. and S. Livingstone Ltd: 1968. • Lambotte A. Le traitement des fractures. Masson, Paris, 1907. • Champy M, Lodde JP. Synthèses mandibulaires. Localisation des synthèses en fonction des contraintes
mandibulaires. Rev Stomatol Chir Maxillofac 77:971–976, 1976. • Luhr HG. The compression‐osteosynthesis of mandibular fractures in dogs. A histologic contribution to primary
bone healing, Eur Surg Res 1: 157–292, 1971.
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3. Material properties
Before beginning to learn how to use a certain material (e.g., wires), it is important to understand what the material is made of, its physical properties, and how to handle it.
3.1. Basic material properties
The elastic behaviour of any material is defined in terms of its stress‐strain response to an external load. Stress and strain refer to the internal state of the material being studied: stress is the internal distribution of the load (defined as force per unit area), whereas strain is the internal distortion produced by the load (defined as deflection per unit length).
For analytical purposes, wires and springs can be considered beams, supported either only on one end or on both ends (e.g., the segment of an arch wire spanning between attachments on adjacent teeth). If a force is applied to such a beam, its response can be measured as the deflection (bending and twisting) produced by the force. Force and deflection are external measurements. In tension, internal stress and strain can be calculated from force and deflection by considering the area and length of the beam.
Three major properties of beam materials are critical in defining their clinical usefulness: strength, stiffness (or its inverse, springiness), and range. Each can be defined by an appropriate reference to a force‐deflection diagram (Fig. 1A).
A B
Figure 1A. A typical force (Y)‐deflection (X) curve for an elastic material like a 0.5‐mm wire where an axial pull (pure stretch) is applied. The stiffness of the material is given by the slope of the linear portion of the curve. The range is the distance along the X‐axis to the point at which permanent deformation occurs (usually taken as the yield point at which 0.1% permanent deformation has occurred). The more vertical the slope, the stiffer the wire.
Figure 1B. Stress (Y) and strain (X) are internal characteristics that can be calculated from measurements of force and deflection, so the general shapes of the force‐deflection and stress‐strain curves are similar. Three different points on a stress‐strain diagram can be taken as representing the strength. The slope of the stress‐strain curve, E, is the modulus of elasticity to which stiffness and springiness are proportional.
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Three different points on a stress‐strain diagram can be taken as representative of the strength of a material (Fig 1B). They represent the maximum load that the material can resist.
• Proportional Limit. The point at which any permanent deformation is first observed. It can also be defined as the elastic limit.
• Yield Strength. The point at which a deformation of 0.1% is measured. • Maximum Load. The point at which the ultimate tensile strength is reached after
some permanent deformation and is greater than the yield strength. The ultimate strength is important clinically because it differs significantly between the steel wires from the newer titanium alloys.
Definitions
1. Springback. This is also referred to as maximum elastic deflection or maximum flexibility. It is related to the ratio of yield strength to the modulus of elasticity of the material (YS/E). Springback is a measure of how far a wire can be deflected without either causing permanent deformation or exceeding the limits of the material.
2. Formability. High formability is ability of a wire to bend into desired configurations, such as loops, without fracture.
3. Biocompatibility and environmental stability. Biocompatibility is resistance to corrosion and tissue tolerance to elements in the wire. Environmental stability ensures the maintenance of desirable properties of the wire for extended times after manufacture, ensuring the predictable behavior of the wire when in use.
4. Joinability. The ability to attach auxiliaries by welding or soldering provides an additional advantage when incorporating modifications into an appliance.
When using wires to immobilize bone fragments or maintain a rigid IMF, it is important to maintain the physical properties of the wires as described above. It is important to stretch or twist the wires in an appropriate range to avoid excessive springback or failure of the wire. In general, when using standard, soft stainless steel wire for IMF procedures, the wires should have been stretched by 10% of the original length to prevent loosening of the wires after insertion. Overstretching hardens the wire, which becomes brittle and difficult to use because it can be easily broken.
In general, the properties of an ideal wire material for IMF purposes should be high strength, low stiffness (in most applications, not for semi‐rigid fixation), high range, and high formability.
In the USA, orthodontic appliance dimensions, including wire sizes, are specified in thousandths of an inch (i.e., 0.016 inch). In Europe, appliance dimensions are specified in millimeters. For this range, a close approximation can be obtained by dividing the dimensions in mils by 4 and placing a decimal point in front (i.e., 0.016 = 16 mils = 0.4 mm).
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3.2. Arch wire properties
3.2.1. Precious metal alloys
Frequently used before 1950, the introduction of stainless steel made precious metal alloys obsolete for surgical purposes. However, silver is still used as the main component of silver cap splints.
3.2.1.1. Stainless steel
Stainless steel with similar properties replaced precious metals in IMF surgery because of considerably better strength and springiness with equivalent corrosion resistance. Stainless steel´s rust resistance results from a relatively high chromium content. A typical formulation for IMF use has 18% chromium and 8% nickel (thus, the material is often referred to as an 18‐8 stainless steel wire).
Steel is softened by annealing and hardened by cold working. Annealing causes changes by heating to above the re‐crystallisation temperature and maintaining a suitable temperature before cooling. Annealing is used to induce ductility, soften material, relieve internal stresses, refine the structure by making it homogeneous, and improve cold‐working properties.
In cases of copper, steel, silver, and brass, this process is performed by substantially heating the material (generally until glowing) and allowing it to cool. Unlike ferrous metals like stainless steel, which must be cooled slowly to anneal, copper, silver, and brass can be cooled slowly in air or quickly by quenching in water. In this fashion, the metal is softened and prepared for further work, such as shaping, stamping, or forming.
Steel wire materials are offered in a range of partially annealed states in which yield strength is progressively enhanced at the cost of formability. The steel wires with the most impressive yield strength (i.e., “super” grades) are almost brittle and will break if bent sharply. Fully annealed stainless steel wires are soft and highly formable. The ligatures used to tie orthodontic arch wires into brackets on the teeth, Kobayashi ties, and IMF cerclage wires are made from such “dead soft” wire like Remanium (Remanit soft – Weich, Dentaurum).
3.2.1.2.. Cobaltchromiumnickel wires (Elgiloy)
Elgiloy, a cobalt‐chromium‐nickel alloy, has the advantage that it can be supplied in a softer and therefore more formable state, and then it can be hardened by heat treatment after being shaped. After heat treatment, the softest Elgiloy becomes equivalent to regular stainless steel, while harder initial grades are equivalent to the “super” steels. For regular IMF procedures, this type of alloy is rarely used.
3.2.1.3. Nickeltitanium (NiTi) alloy
The name nitinol was derived from the elements that make up this alloy ("ni" for nickel and "ti" for titanium) and from its place of origin ("nol" for Naval Ordinance Laboratory). Orthodontic
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wires are often made of this alloy, and a surgeon may encounter it during an orthognathic procedure.
The high springback property of nitinol is useful in cases that require large deflections but low forces. Nitinol wires have greater springback and a larger recoverable energy than stainless steel or beta‐titanium wires when subjected to the same amount of bending or torquing.
Like stainless steel and many other alloys, NiTi can exist in more than one form or crystal structure. The martensite form exists at lower temperatures, and the austenite form exists at higher temperatures. For steel and almost all other metals, the phase change occurs at a transition temperature of hundreds of degrees. Both shape memory and superelasticity are related to phase transitions within the NiTi alloy.
3.3. Bands
Rubber bands are extensively used in orthognathic surgery to transmit force from the upper jaw to the lower jaw via the dentition. Rubber has the particularly valuable quality of a great elastic range, so that the extreme stretching produced when a patient opens the mouth while wearing rubber bands can be tolerated without destroying the appliance. The greatest problem with all types of rubber is that they absorb water and deteriorate under intraoral conditions. The elastics we use are made of latex instead of gum rubber, with a useful performance that is 4 to 6 times as long. Latex allergy forces us to also use non‐latex rubber bands, which have considerably less durability (Fig. 2).
Figure 2. Latex (beige ‐ left) and non‐latex (whitish ‐ right) bands with an application tool (bottom).
Small elastomeric ligature modules (e.g., Sanitie, GAC) replace wire ligature ties to hold arch wires in brackets for many applications. These modules are most easily applied with either a twirl‐on‐instrument or mosquito (Fig. 3A and B).
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Figure 3A. Elastomeric modules and mosquito.
Figure 3B. A module can be mounted using a mosquito (displayed, most convenient for surgeons) or with a twirl‐on instrument or shooter (not displayed).
Like rubber, however, these elastomeric modules tend to deteriorate after a relatively short time in the mouth.
REFERENCES
• Kusy RP, Diley GJ, Whitley JQ. Mechanical properties of stainless steel orthodontic archwires. Clin Materials 3:41‐59, 1988
• Miura F, Mogi M, Ohura Y. The super‐elastic property of the Japanese NiTi alloy wire for use in orthodontics. Am J Orthod 90:1‐10, 1986
• Kusy RP. The future of othodontic materials: the long view. Am J Orthod Dentofac Orthop 113:91‐95, 1998 • Josell SD, Leiss JB, Ekow ED. Force degradation in elastomeric chains. Sem Orthod 3:189‐197, 1997
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4. Protection from prick accidents
Infection control is indicated for all patients, regardless of the presence of infectious disease. Such practices aim to avoid direct contact of health care personnel with organic materials. This is achieved using a protective barrier, such as gloves, to prevent skin contact with blood, secretions, or mucosa.
Glove perforations may occur during surgical procedures, even though they often are not noticed during the procedure. The rate of perforations is directly related to the duration of the surgical procedure, the type of procedure performed, and the quality of the glove used. In maxillo‐facial surgical procedures, the incidence of glove perforation appears to be more closely associated with the type of surgical procedure than with the duration of surgery.
During IMF procedures, especially with wire splinting, there is an increased risk of prick accidents. Handling of sharp instruments like wires heightens the risk of glove perforation so drastically that often, perforations can be found within a few minutes after the start of surgery. Additionally, many of these procedures are performed by surgeons‐in‐training who sometimes have never been taught how to perform an IMF procedure safely.
To avoid this kind of accident, some basic rules should be followed:
• Whenever possible, try to perform the IMF procedure in a surgical setting with an assistant.
• Always use double‐glove protection (e.g., Indicator gloves – Mölnlycke) (Figs. 4 and 5).
• Pay attention to all sharp edges. Once you have already twisted the wires, cut them off and twist the tips with an instrument to avoid inadvertent pricks.
• During the procedure, keep the pliers and twisters away from the wires to avoid pricking during instrument handling.
• Changing gloves at regular intervals is recommended as well as whenever any evidence of accidental perforation is suspected or noticed.
• Take your time!! At the beginning, these procedures may be challenging for inexperienced surgeons before sufficient dexterity is achieved.
Many authors recommend changing gloves every 120 minutes; others like Gaujac et al. (2007) suggest glove changing after Erich splint placement in each dental arch.
The low number of perforations in the inner gloves demonstrates the effectiveness of double‐gloving protection with either two sterile surgical gloves or a non‐sterile glove under a sterile surgical glove. The use of clean, non‐sterile procedure gloves for minimally invasive surgical procedures is viable and free of risks or complications.
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Figure 4. Double‐gloving technique with sterile green gloves (Indicator, Mölnlycke).
Figure 5. A puncture hole is readily visible in a wet environment.
The Council of the European Union adopted a directive aimed at achieving the safest possible working environment for health care workers through prevention from sharp injuries. The aim of the directive is to protect workers at risk from injuries due to medical “sharps” (including needle sticks). The directive provides for an integrated approach to risk assessment, risk prevention, training, information, awareness raising and monitoring, and for response and follow‐up procedures. The new directive makes the framework agreement between the employers and trade unions of the hospital and health care sectors legal.
REFERENCES
• Gaujac C, Ceccheti MM, Yonezaki F, García Jr. IR, Peres P. Comparative analysis of 2 techniques of double‐gloving protection during arch bar placement for intermaxillary fixation. J Oral Maxillofac Surg 65:1922‐1925, 2007
• Molinari JA. Gloves: Continuing effectiveness, new technologies, and recommendations. Compendium 21:186, 2000
• Giglio JA, Roland RW, Laskin DM, et al. The use of sterile versus nonsterile gloves during out‐patient exodontia. Quintessence Int 24:543, 1993
• Avery CME, Taylor J, Johnson PA. Double‐gloving and system for identifying glove perforations in maxillofacial trauma surgery. Br J Oral Maxillofac Surg 37:316, 1999
• Burke FJT, Baggett FJ, Lomax AM. Assessment of risk of glove puncture during oral surgery procedures. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 82:18, 1996
• Patton LL, Campbell TL, Evers SP. Prevalence of glove perforations during double‐gloving for dental procedures. Gen Dent 43:22, 1995
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• Baggett FJ, Burke FJT, Wilson NHF. An assessment of the incidence of punctures in gloves when worn for routine operative procedures. Br Dent J 174:412, 1993
• Otis LL, Cottone JA. Prevalence of perforations in disposable latex gloves during routine dental treatment. J Am Dent Assoc 118:321, 1989
• Pieper SP, Schimmele SR, Johnson JA, et al. A prospective study of the efficacy of various gloving techniques in the application of Erich arch bars. J Oral Maxillofac Surg 53:1174, 1995
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5. Dental trauma
The aim of splinting is the stabilisation of the injured tooth in its normal anatomical position during the healing period. The requirements for an acceptable splint are the following:
• The materials to fabricate the splint should be part of the office armamentarium. • Additional manipulation of the injured tooth should be minimal. • The tooth should remain in its normal position throughout the immobilization period. • Affecting the gingival tissue and interference with the occlusion should be avoided. • Easy access should be provided for endodontic treatment. • Teeth should be pulp‐tested. • Oral hygiene should be maintained. • Removal should be easy.
The splints that come closest to fulfilling the above requirements are the acid‐etched resin arch wire splints and the orthodontic bracket arch wire splints. These, of course, are difficult to apply when blood and saliva cannot be isolated from the field, such as in an emergency room.
A rigid splint increases the amount of external resorption and eventual early loss of the tooth. For this reason, arch bars and other forms of interdental wiring are less than optimal.
An acid‐etch resin splint is easy to fabricate but does not allow much tooth mobility. A better splint would be an acid‐etch resin arch wire splint.
A splint should be left on the tooth for a minimal amount of time. Prolonged splinting will increase the amount of ankylosis. The optimal splinting period for a displaced or avulsed tooth is empirically based. Ideally, the splint should be maintained for 7‐10 days because the gingival fibers usually heal after 1 week, and this time should provide adequate periodontal support.
Alveolar bone fractures with replanted teeth may require a splint for 3‐4 weeks, luxation may require a splint for 2‐8 weeks, and root fractures require a splint for 12 weeks.
5.1. Acidetch resin arch wire splint Armamentarium
• Stainless steel wire loop, 0.4 mm in diameter • Light‐curing resin (Ketac™ Nano or Transbond™, 3M ESPE) • Bonding agent (Adper™ Single Bond Dental Adhesive, 3M ESPE) • Orthophosphoric acid (Transbond XT Etching Gel System, 3M ESPE) • Toothpicks
The wire is conformed to the facial surfaces of the teeth to be splinted (Fig. 6). At least one tooth on either side of the displaced tooth or teeth must be included. Toothpicks, when available, help to keep the labial part of the wire in the mid‐portion of the crown and, at the same time,
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decrease papillary bleeding (Fig. 7). It is important to ensure that the dental toothpicks keep the injured tooth in a neutral position and do not displace the loosened teeth.
Figure 6. A twisted 0.014 Kobayashi tie hook of 0.4‐mm Remanium soft wire serves as the basis for the resin‐wire splint.
Figure 7. Toothpicks help to keep the wire in the mid‐portion of the crown.
The facial surfaces of all the teeth to be splinted are etched with phosphoric acid for 1 minute, after which they are washed and dried. The bonding agent is applied, and a small amount of resin is placed in the middle of the facial surface. A flowing, light‐cured composite is applied with a syringe. The composite is applied first on non‐injured teeth. The injured tooth is supported by finger pressure, and the twisted wire is repositioned, adding extra composite where required (Fig. 8). Flexibility of the splint is achieved by leaving some free wire interdentally. The surgeon must be sure that the displaced tooth is in the correct position. A radiograph should be taken to verify the position after the splint is in place.
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Figure 8. Acid‐etch wire resin splint
The resin material should not contact the gingiva because it will cause gingival inflammation. The patient should be instructed in proper oral hygiene, stressing the importance of keeping the gingival crevice as well as the rest of the teeth clean. When the splint is removed, the wire can be cut between the teeth; however, the resin should be kept in place because the replanted teeth will still be loose and can be displaced. After 2‐3 months when the teeth are firmly attached, the resin can be removed.
5.2. Orthodontic bracket arch wire splint
The use of an orthodontic bracket arch wire splint is an excellent technique. Acid‐etched brackets are placed on the displaced tooth or teeth as well as on at least one sound tooth on either side of the displaced tooth. Sometimes, it is necessary to extend this type of splint by banding the permanent first molars. This extension may occur in the mixed dentition when permanent lateral incisors, canines, and/or premolars are absent or there is a deep overbite and additional teeth are necessary for stabilisation. The arch wire can be either round or rectangular and is bent to conform to the facial surfaces of the teeth to be splinted. Ligatures are used to hold the arch wire in the brackets. The advantage of this type of splint over the acid‐etch resin arch wire splint is that the practitioner can remove the elastic ligatures and the wire to assess the mobility of the displaced teeth. If there is excessive mobility, the splint can be replaced.
It should be noted that a fairly high percentage of teeth involved in alveolar process fractures undergo pulpal necrosis as well as either internal or external resorption. This may occur even years later. The teeth must be carefully observed and endodontic intervention initiated at the appropriate time.
REFERENCES
• Feliciano KMPC, de Franca Caldas Jr A. A systematic review of the diagnostic classifications of traumatic dental injuries. Dent Traumatol 22:71‐76, 2006
• Gassner R, Bösch R, Tuli T, Rüdiger E. Prevalence of dental trauma in 6000 patients with facial injuries: Implications for prevention. Oral Surg Oral Med Oral Pathol 87:27‐33, 1999
• Kaste LM, Gift HC, Bhat M, Swango PA. Prevalence of incisor trauma in persons 6 to 50 years of age: United States, 1988‐1991. J Dent Res 75:696‐705, 1996
• Andreasen JO. Textbook and color atlas of traumatic injuries to the teeth. Copenhagen: Munksgaard; 1994 • Fried I, Erickson P. Anterior tooth trauma in the primary dentition: incidence, classification, treatment methods
and sequelae: a review of the literature. ASDC J Dent Child 62:256‐261, 1995 • Gutman JL, Gutman MSE. Cause, incidence, and prevention of trauma to teeth. Dent Clin North Am 39:1‐13, 1995 • Oikarinen KS. Clinical management of injuries to the maxilla, mandible, and alveolus. Dent Clin North Am 39:113‐
131, 1995
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• Krasner P, Rankow HJ. New philosophy for the treatment of avulsed teeth. Oral Surg Oral Med Oral Pathol 79:616‐626, 1995
• Protocol of the International Dental Trauma Association 2007
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6. IMF techniques
The first and most important aspect of surgical correction of mandibular fractures is to reduce the fracture properly. In the tooth‐bearing bones, it is of outermost importance to place the teeth in a pre‐injury, occlusal relationship. Merely aligning the bone fragments at the fracture site without first establishing a proper occlusal relationship rarely results in satisfactory postoperative functional occlusion.
With interdental fractures, fracture models are important: impressions poured in Snow‐White plaster and sectioned at the fracture site allow the assessment of pre‐trauma occlusion. Missing teeth, pre‐existing class II or III, and deep bite deformities may otherwise misguide the surgeon.
To establish a proper occlusal relationship, several techniques have been described, generally referred to as IMF. The most common technique includes the use of a prefabricated arch bar that is adapted and circumdentally wired to the teeth or acid‐etch bonded to each arch; the maxillary arch bar is wired to the mandibular arch bar, thereby placing the teeth in their proper relationship. Other wiring techniques, such as Ivy loops or Obwegeser continuous loop wiring, have also been used for the same purpose.
6.1. Ligature wiring
Inmobilisation of fractured jaw fragments and fixation in the correct dental relationship by means of dental intermaxillary wiring was first advocated in the USA by Gilmer in 1887. IMF or maxillo‐mandibular fixation consists of wiring the mandibular teeth to those of the maxilla in adequate occlusal relationships: the jaw is immobilised in a fixed, mouth‐closed position.
For general considerations, if immobilisation of the jaws is required for a short period of time, relatively simple wiring methods are used. Such cases are normally performed under local anaesthesia with or without sedation. With an uncooperative patient or a more difficult fracture that requires immobilisation for several weeks, general anaesthesia and endotracheal intubation are recommended.
All procedures should begin by cleansing the oral cavity with a suitable antiseptic solution such as aqueous chlorhexidine. Good illumination, efficient suction, and soft tissue retraction are necessary. Under general anaesthesia, a throat pack and cuffed endotracheal tube are essential. Even with skilled assistance, a complex IMF wiring procedure, like full eyelet wiring and IMF, may take 1 hour or longer.
• One should acquire the habit of always twisting the wires in a single direction, usually clockwise, to avoid confusion. This habit also avoids breakage, which may occur when the wires are twisted first in one direction and then in the other.
• It is useful to stretch the wire, so that it will have no bends or easily slip through the interdental spaces.
• It is necessary to give the wires a few additional turns for tightening purposes.
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Before tightening the IMF wires, ALWAYS REMOVE THE THROAT PACK OR ANY CLOTS OR FOREIGN BODIES!
6.1.1. Gilmer wiring
This technique provides a simple and rapid method to immobilise the jaws. However, the wires tend to loosen, and a broken, direct wire cannot be replaced without first removing and replacing all of the other wires. A 15‐cm length of prestreched, 0.4‐mm soft stainless steel wire is passed around the necks of all of the available teeth, and the ends of the wire are twisted in a clockwise direction until the wire is tightly bound, leaving a 3‐cm tail (Fig. 9).
Figure 9. Gilmer wires twisted.
An appropriate number of wires is thus placed around the selected teeth in both the upper and lower jaw.
The teeth are brought into an adequate occlusal relationship. IMF is achieved after reduction of the fracture by twisting the separate wire tails together, obtaining cross‐bracing wherever possible (Fig. 10).
Figure 10. IMF with Gilmer wires.
The cut ends should be bent into the interdental spaces to avoid soft tissue trauma. Sometimes, this is not feasible, and then it is recommended to cover the wire twists with orthodontic wax (Utility wax strips, Heraeus Kulzer).
The inconvenience of this method is that the jaws must be constantly immobilised during the period of treatment and the mouth cannot be opened for either inspection or hygiene. This
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procedure should only be considered to achieve temporary inmobilisation of fractured fragments. When applied too long, gravity and speech will induce extrusion of teeth.
6.1.2. Kazanjian button
This method is particularly useful for immobilisation by intermaxillary orthodontic‐type rubber bands, but should only be considered a temporary method.
Armamentarium
0.4‐mm stainless steel wire, stretched 10% to a 15‐cm length Wire cutters and wiring forceps Luniatschek1 Cheek and tongue retractors Good illumination and suction device Rubber bands
Usually, two teeth are utilised to support the button. A wire is passed around the neck of each tooth and twisted together (Fig. 11).
Figure 11. Wires are prepared to twist into a Kazanjian button.
The two twisted wires are then re‐twisted and cut approximately 2.5 cm from the teeth (Fig. 12). The remaining ends of the wire are then shaped into a small button (Fig. 13).
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1 Luniatschek: Gauze packer; receives its name from a German dentist. It is very useful to handle the wires as their tips terminate in double spikes that guide the wire.
Figure 12. Wires twisted to form the Kazanjian button.
Figure 13. Elastic band IMF on Kazanjian buttons.
Premolar teeth, or a premolar and a molar, form substantial anchors for the button. If anterior teeth are selected, 0.3‐mm stainless steel wire should be used. The upper and lower anterior teeth should be wired in pairs for additional strength, as described for intermaxillary wiring. All four mandibular incisors should be joined.
6.1.3. Eyelet technique
Provided that teeth of a suitable number, shape, and quality are present on each fragment, eyelet wiring (Eby, 1920; Ivy, 1922) is a simple and effective method for the reduction and immobilisation of jaw fractures. Eyelet wires may also be used in combination with Gunning‐type splints in an opposing edentulous jaw, and arch bars or cap splints can be used in a partially dentate jaw. Robert Ivy described the wire passing through the loop of the eyelet.
This technique has the advantage that fixation may be released by removal of the intermaxillary ligatures.
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Armamentarium
10 and preferably 20 prepacked autoclaved eyelet wires of 0.4‐mm stainless steel wire, stretched 10% to a 5‐cm length
Bundle of 20 tie wires, 0.5‐mm diameter and 15‐cm long, of prestretched, soft stainless steel wire
Wire cutters and wiring forceps Luniatschek Cheek and tongue retractors Good illumination and suction device
Eyelet wires are usually constructed from 0.4‐mm diameter soft stainless steel wire, which should be stretched by 10% of the original length so as to prevent loosening of the wires after insertion. Overstretching hardens the wire, which then becomes brittle.
Suitable lengths of the wire, for example, 1 meter, are cut and, with each end held by hemostats, the wire is stretched by 10% or by an additional 10 cm. It is then further divided into 15‐cm lengths.
Eyelet wires are made by twisting the middle of each length of wire around the shaft of a 3‐mm‐diameter rod, which is held in a vice (Fig. 14). Three or four twists suffice, and the ends of the eyelet wire are cut off obliquely to equalise their lengths and produce a sharp point, which will readily pass through the interdental space. Quantities of eyelet wires are collected in bundles of approximately 14 by passing a safety pin or prefabricated wire loop through each eyelet. These should be packed and autoclaved to be ready for immediate use.
Figure 14. Preparing eyelets.
For general consideration, if immobilisation of the jaws is required for a short time, relatively few eyelets are necessary, for example, one or two in each quadrant.
The wire shafts are first curved and then gripped by a modified hemostat or special clip at the midpoint of the curve so that they can be readily passed through the interdental space without engaging, if possible, the interdental papillae or the lingual or palatal tissues.
After selecting the teeth to be wired, both ends of the eyelet wire are inserted through the interdental space from the outer surfaces of the teeth (Fig. 15A, 15B). As the wires emerge on the lingual or palatal side, they are gripped by a second pair of forceps that is manipulated by an
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assistant who, after bending them, passes the wires back through the adjacent mesial and distal interdental spaces. The operator grips each wire as it emerges from the space and pulls it through.
A 1
B
Figure 15A and 15B. Ivy or Eby eyelet inserted into the interdental space.
C D
Figure 15C. Wire passing through the loop allows for less tightening than passing behind the eyelet (Figure 15D).
One end is drawn around the medial tooth, and the other end is drawn around the distal tooth; the distal wire is inserted through the loop of the eyelet (Fig. 15 C), and both wire shafts are pulled tight in unison and then twisted tightly together as the assistant maintains the lingual or palatal portion below the maximum diameter of the two teeth with a suitable instrument (e.g., Luniatschek)
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Alternatively, the wire can be passed behind the loop providing a greater fixation for the eyelet. (Fig. 15D). In the upper jaw, the eyelets should project above, and in the lower jaw, below the horizontal twist; this prevents the ends from affecting each other (Figure 16).
Figure 16. When enough eyelets are set in place intermaxillary fixation is accomplished by threading wire ligatures through the eyelets.
The ends of the wire are cut and bent into interdental spaces to prevent irritation of the lip or cheek, provided no further wires are to be passed through. A number of teeth on each side of the jaw are prepared in this manner.
Vertical, anteroposterior, and lateral movements of the jaw must be controlled during the period of immobilisation. For example, with a full complement of teeth and depending upon the fracture site, eyelets may be inserted between the first and second upper molars, the premolars, the lateral incisor, and the canine and central incisors; in the lower jaw, eyelets may be inserted between the central and lateral incisors, the premolar teeth, and the first and second molars.
The lower incisors do not have an ideal shape for eyelet wire retention and are frequently overcrowded, making insertion of the wires more difficult. In such cases, the wiring pattern can be modified to avoid using the lower incisor teeth. Patients with a developmental anterior open bite may have excessive traction applied to the lower anterior teeth, which can be avulsed. Acquired anterior open bites, resulting from fracture/dislocation of the mandibular condyles, should not cause this problem, provided that the patient is sufficiently relaxed.
When some teeth are missing but not enough to require an arch bar, or the fracture site is unsuitable, a wire can be attached to an isolated tooth by forming a clove hitch and, after tightening the wire loop, passing one end of the wire through an eyelet in the opposing jaw and twisting it together with the other end.
Clove hitch (Fig. 17A‐C)
• Although the use of a simple clove hitch around a single isolated tooth is simple and rapid, it has the disadvantage that, should the end of the wire that is used as a tie wire break, the whole wire must be replaced.
• After placing the clove hitch over the isolated tooth, the loops are tightened, and the wire is pushed beneath the neck of the tooth and the ends then twisted in a
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clockwise direction (FIG. 17A‐B). When using a simple clove hitch, the longer shaft is inserted through the opposing the eyelet, achieving by this way the IMF.
Figure 17A. Clove hitch. Figure 17B. Clove wire tightened
Figure 17C. Clove hitch‐eyelet IMF
• Whenever possible it is better to use an eyelet wire and separate tie wires. One shaft of the wire is formed into a clove hitch as shown (Fig 17D, 17E).
• A tie wire is passed through the eyelet, secured to the lower freestanding tooth, and connected to an eyelet around an upper mesial or anterior pair of teeth. Finally, the crossed ends of the wire ligatures are then cut short and tucked into their respective upper interdental spaces (Fig 17F).
D E
Figure 17D. Clove‐hitch with eyelet. Figure 17E. Clove‐hitch with eyelet tightened.
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F
Figure 17F. IMF with a wire ligature passed through eyelets.
After insertion, the eyelet and tie wires may loosen as a result of minor tooth movement and/or wire stretching, leading to jaw mobility. The arrangement of the tie wires in a “V” pattern minimises this tendency.
The opposing eyelets are connected by passing a third wire through them and twisting the wire to draw the teeth and jaws together or attaching orthodontic‐type rubber bands (Fig. 18A, 18B). A 0.5‐mm wire is used, one end held in a forceps or artery clip while the other end is bent into a small hook or double angle that is passed through the eyelet so that it can be gripped and then pulled through by the assistant.
Figure 18A. IMF on eyelets.
Figure 18B. The wire ligature fixing a pair of eyelets is shown in greater detail. Obviously, a tie wire in triangular formation would do better.
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Before tightening the wires, it is essential to reduce the fractures. Once a proper occlusion has been achieved, the posterior teeth should be tightened to avoid excessive traction on the lower anterior teeth.
Throughout the period of jaw immobilisation copious oral lavage is required, particularly after each meal. To remove the eyelets after the immobilisation period, it is advisable to remove first the tie wires to enable a limited amount of jaw opening to facilitate their removal. One may leave the eyelets even for a week to control bony union by checking the occlusion. Afterwards, eyelet wires are removed after loosening the wire by twisting in a counter‐clockwise rotation so that the buccal wire can be cut.
6.1.4. Intermaxillary loop wiring (Stout)
This method (Stout, 1942) requires the presence of at least three adjacent teeth. The wires form a number of loops along the buccal side of the alveolar process, which is especially useful when elastic bands are used for traction.
Armamentarium
30‐cm length of soft, 0.5‐mm stainless steel wire, stretched 10% to a 15‐cm length
Wire cutters and wiring forceps Luniatschek Cheek and tongue retractors Good illumination and suction device
The wire is passed through the interdental space between the second and third molars.
Figure 19. Stout wiring, wire passing through the interdental space between the second and third molar.
The buccal portion of the wire is placed against the gingival margins of the teeth selected for wiring, and a soft metal bar or rod, about 3 mm in diameter and 5 cm in length, is passed through the wire loop and laid along the buccal surface of the segment parallel to the buccal wire (Fig. 19A, 19B). The lingual portion of the wire is passed through each interdental space in turn, forming a loop over the bar and buccal portion of the wire, and then is returned lingually through the same interdental space.
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When the required number of teeth has been wired, the ends of the buccal and lingual portions of the wire are twisted together in either the bicuspid or cuspid region. The arch bar is then removed, leaving a series of loops on the buccal side. Each loop is twisted twice, first the posterior and then each succeeding loop, which are then bent to form a hook. If a tooth is missing, the buccal and lingual arms of the wire are twisted to bridge the space, and the loop process is continued.
Figure 20. Elastic bands or wire IMF on Stout ligatures.
Each loop is then tightened in turn, closely adapting the buccal wire into the interdental spaces until rigid. These are finally bent towards the sulcus if elastic traction is to be used or towards the occlusal surface of the tooth if tie wires are intended (Fig. 20).
6.1.5. Cable arch wire (Fig. 21)
A strand of fine‐gauge stainless steel wire (0.4 mm) is passed around the neck of a molar and twisted tightly (Fig. 21A). The ends are left long since the wire acts as a pivot for the following wires and must extend to the opposite molar. Wires (0.3‐0.4 mm) are then similarly anchored to the other teeth (Fig. 21B), and each is successively twisted about the pivot wire for four or five turns (Fig. 21C). This procedure is continued until a molar on the opposite side is reached (Fig.21D)
A B
Figure 21A. Arch wire tighted around the last molar Figure 21B. Wire ligatures anchored to the teeth.
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C D
Figure 21C. Cable arch wire being tightened. Figure 21D. Cable arch wire completed.
6.1.6. Multiple loop wiring (Obwegeser method)
Armamentarium
0.5‐mm stainless steel wire, stretched 10% to a 30‐cm length Obwegesser template (Medicon USA: 68.04.92) Wire cutters and wiring forceps (Medicon USA: 68.04.90) Silk ligature may be useful Luniastchek Obwegeser wire loop clip (Stryker) Cheek and tongue retractors Good illumination and suction device
A 30‐cm long, soft stainless steel wire, 0.5‐mm diameter, is bent to form an arcade, which conforms to the lingual or palatal aspects of the selected block of teeth (Fig. 22). The distal end is left long so that it can be passed between the last two molars. A template may be useful for the beginner (Fig. 23).
Figure 22. Multiple loops in sizes matching the cervices.
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Figure 23. Template for Obwegeser ligature.
Pliers are applied at the point where the wire bends back to follow the contour of the adjacent tooth, thus pinching the two portions tightly together. The projecting sections of the attached ligatures are given half a turn to align them vertically.
After the posterior end of the wire has been passed between the last two molar teeth and brought forward anteriorly on the buccal aspect, the preformed wire is inserted into the mouth, and the pinched loops are gently passed with a curved hemostat through the interdental spaces (Fig. 24 A and B)).
A B
Figure 24A and B. Loops pinched, turned vertically, and passed with a hemostat through the interdental spaces.
The long end of the wire is passed through all of the loops (Fig. 24 C). Both ends of the wire are twisted together anteriorly. A special Obwegeser wire loop forceps (Fig. 24 D) twists each loop tightly to the buccal wire, thus adapting it close to the interdental space. The loops are then bent toward the occlusal surfaces for the tie wires, or the gingiva for elastic traction as required (Fig. 24 E).
C D E
Figure 24C. The buccal wire is passed trough the loops, from posterior to anterior.
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Figure 24D. A special wire twister is used to twist the loops into eyelets. Eyelet length is controlled by adjusting the anterior twist inbetween two eyelet twists.
Figure 24E. Final tightening should be done gently, as wire fracture forces one to repeat the whole procedure.
Usually, six segments are wired: canine to second molar on each side, canine to canine in the front. It takes some experience to bend the segmental wires to fit the different tooth diameters such that the eyelet is not too long and becomes useless for intermaxillary ligature wiring. A template is useful in this respect. The Obwegeser wire loop forceps is mandatory to tighten the wire and maintain the loops at an appropriate size.
6.1.7. Leonard’s button wiring (Fig. 25)
Leonard (1977) considered that eyelet wires have several drawbacks:
• A simple eyelet is frequently drawn into the interdental space, making it difficult to use.
• Elastic traction using eyelets, though possible, is time consuming to apply.
Leonard described the use of titanium buttons of 8‐mm diameter, inclusive of a 1‐mm rim, and 2‐mm deep. Each button had two 1‐mm diameter holes, 1‐mm apart. The ends of 15‐cm lengths of 0.4‐mm wire are passed through the holes and then twisted twice together on the deep surface. The button is then ligated to the teeth in a similar manner to the eyelet wires, leaving the button over the interdental space, and the distal wire is brought forward and passed through the twist on the deep aspect of the button. IMF is easily achieved using stainless steel tie wires or elastic bands fixed around opposite buttons in an unusual pattern.
This technique is not amenable for patients with a severe posterior crossbite or marked anterior overbite, where there is a lack of space for the buttons.
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Figure 25. Leonard’s button.
6.1.8. Banded retention appliance
The methods of fixation described previously are readily available and applicable without special dental or prosthodontic facilities. More precise types of appliances may be custom‐made from impressions of the teeth. With careful and gentle techniques, and with the help of local anesthesia, dental impressions may be taken of jaw fractures without causing the patient undue discomfort. Bands are supplied from the laboratory with hooks soldered to the buccal surface for intermaxillary wiring; these can be utilised to anchor arch bars. Such appliances may also provide attachments for auxiliary soft tissue support.
One of the most useful types is the banded retention appliance (Fig. 26A), a practical application of the edgewise wire appliance employed by orthodontists. It consists of metal bands fitted around selected teeth and connected with wire. This type of appliance not only assures fixation of the fragments but also permits lower jaw function. Additional advantages of these devices are that they are less bulky and more hygienic than other appliances, and minimise possible injury to gingival tissues. Such a definitive type of appliance can be constructed rapidly.
Another possibility is the adjustable banded arch bar for fixation of mandibular fractures. In this case a wire is soldered to band to serve as an arch bar. Then, teeth are attached to bar with simple ligatures (Fig. 26B). These splints can be prefabricated and held in readiness for use.
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Figure 26A. Orthodontic type bands are fitted to 2 adjacent teeth. Bands are welded together by solder and the horizontal tube is also soldered to buccal surface of bands.
Figure 26B. The adjustable banded arch bar retention device: An arch bar connected to orthodontic bands. Teeth are attached to bar with simple ligatures.
6.2. Arch bar techniques
Another method, which provides monomaxillary as well as IMF, is the arch bar technique. There are basically two varieties of arch bars, those that are commercially produced and those that are custom‐made.
General indications:
• When insufficient teeth remain to allow efficient eyelet wiring.
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• When the teeth present are so distributed that efficient IMF is otherwise impossible.
• When there are simple dentoalveolar fractures or where multiple tooth‐bearing fragments in either jaw require reduction into an arch form, before IMF is applied.
• As an integral part of internal skeletal suspension in the treatment of fractures involving the middle third of the facial skeleton.
• To reduce the preoperative time that would otherwise be required for cap splint preparation.
The advantage of custom‐made arch bars is that they are fashioned on fracture models and therefore contribute to the reduction as well as stabilisation of the fracture at the level of the dental crowns. They can be rapidly provided by an experienced technician and will not delay fracture treatment.
Half‐round Remanium laboratory stainless steel coils (1500 N/mm2, Dentaurum) are shaped around the dental cervices. Remanium ball retainer clasps of similar rigidity are point‐soldered to the main arch bar. The solder point is strengthened by white‐yellow universal solder. The arch bar is then polished.
Preoperative impressions of the teeth are taken so that a maxillofacial technician can assess the models to determine the correct articulation of the teeth. However, preoperative impressions may be both painful and difficult, and separate impressions of each fracture segment may be required. Disposable trays and reduced peripheral flanges, particularly on the lingual side, will facilitate this procedure.
Custom‐made splints save considerable operative time and difficulty. Alternatively, if such a splint is not available, various types of commercially prepared arch bars can be easily adapted by the surgeon at the cost of prolonging the operation time. The technique to fixate the Groningen splint is similar to that described for the Erich arch bar.
6.2.1. Groningentype custommade arch bar
This arch bar is useful when extra rigidity is required, for example, in case of segmental osteotomies.
Technique
Step 1. Trim the models to allow access to the cervical areas and smooth the buccal sulcus (Fig. 27). Draw the cervical contours with a thick pencil. Endpoints are situated at the last tooth in the arch.
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Figure 27
Step 2. Adapt the main arch bar with Waldsach pliers. The arch bar must lie passively on the model. (Fig. 28).
Figure 28. Passive contact of the arch bar and the cervices.
Step 3. Distribute approximately eight hooks of 3 to 4 mm behind the canine teeth, away from the interdental spaces (Fig. 29).
Figure 29. Marking of the hook at the level of the interdental spaces.
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Step 4. With a carborandum disc, make grooves in the arch bar where the hook will be point‐welded (Fig. 30). The hook may not touch the sulcus.
Figure 30. Preparing the welding of the hooks by roughening the arch bar.
With a fine flame, fill the voids between the arch bar and the hooks by welding (Fig. 31).
Figure 31. Welding the hooks.
Step 5. Finish with the carborandum disk, with sandblasting (50 μm), and again with red carborandum stones (Fig. 32).
Figure 32. Polishing the arch bar.
Step 6. Finish with chrome cobalt rubbers and polish with pumice using high polish for metal (Fig. 33). 42
Figure 33. Highly polished arch bar.
Armamentarium
Point‐welding device (Dentaurum) Propane/compressed air Waldsach pliers (Dentaurum) Dentaurum wire: Remanium “hart” 2.40mm × 1.40 mm/94 × 55 (10
m) order #: 385‐624‐00 PD universal solder “White” Produits Dentaires CH‐1800 Vevey Suisse
(630°‐680°)
6.2.2. Erich arch bar
Prefabricated arch bars are available commercially, the most popular of which is the Erich arch bar. These arch bars are made of a relatively soft metal, which can be molded and adapted to the dental arch.
Armamentarium (Fig. 34A)
Erich Arch Bar (e.g., Hu‐Friedy ‐ code WPAB‐, Stryker) 0.5‐ and 0.4‐mm stainless steel wire, stretched 10% to a 15‐cm length Wire cutters and wiring forceps Luniatchek Cheek and tongue retractors Good illumination and suction device
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Figure 34A. Basic IMF armamentarium
.
Each bar has hook‐like projections, which are placed in an upward direction in the upper jaw and in a downward direction in the lower jaw (Fig. 34B).
Figure 34B. Erich bar fixed to the upper dentition.
Technique
If sufficient teeth are available, it is advisable to place and secure the wires away from the fracture site to avoid unexpected subluxation of the teeth adjacent to the fracture site. In addition, providing there is adequate fixation of the arch bar in the posterior segments, it is recommended to leave the inferior incisors unattached to the arch bar to avoid their extrusion.
The arch bar is initially cut to a suitable length and afterwards is bent to adapt to the curvature of the teeth. One‐half of the arch is measured with the end of the loop, and then twice the distance is cut off.
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The arch bar is fixed by passing 0.4‐mm (although some surgeons prefer 0.5‐mm wires, especially for the posterior segments) stainless steel wire ligatures around the neck of each available tooth (keep the wires below the greater circumference of the teeth by pressing the wire apically with the aid of an assistant holding an instrument like the Luniatschek while tightening the wire). The wires are twisted tightly to anchor the bar to the dental arch.
There are several methods to perform this procedure:
• Passing the wire around the lingual or palatal aspect of the tooth and tightening it over the bar (Fig. 34B).
• Passing the wire circumferentially around the entire tooth before tightening it over the bar (Fig. 35A, 35B).
• Both ends of the wire loop are passed around the tooth (Fig. 35C); one end passes over the bar and is inserted through the loop while the other end passes under the bar and remains free of the loop( Fig. 35D, 35E). The two ends are pulled to tighten the loop, and the wires are then twisted over the bar (Fig. 35F).
• Both ends of the wire loop may be passed either above or below the arch bar and through a single interdental space (Fig.36A). The ends are then pulled separately around the teeth, lying immediately mesially and distally, one over and one under the bar, before being tightened (Fig. 36B). This method distributes the load over two teeth (Fig. 36C).
Each slightly more complex method gives an increasing rigidity of fixation.
Figure 34B. Wire passed around the tooth, twisted directly over the bar.
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Figure 35A.Wire twisted circumferentially around the tooth. Figure 35B. Wire tightened over the Erich bar.
Figure 35C. Both ends of the wire are passed around the tooth. Figure 35D. The bar is passed through the first loop.
Figure 35D. One end passes over the bar and is inserted Figure 35E. The wire is tightened over the bar.
through the loop while the other end passes under the bar.
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Figure 36A. Both ends of the loop passed above the bar. Figure 36B. Wire ends pulled mesially and distally over the bar.
Figure 36C. Wires tightened over the bar across several teeth.
IMF is obtained by placing orthodontic elastic bands or wires between the hooks of the upper and lower arches. The tie wires are first pulled, tightened, and then cut so that the ends can be bent over the bar into an interdental space to avoid soft tissue injury. Release of the IMF is obtained by removing the intermaxillary elastic bands or wires (Fig. 36 D).
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Figure 36D. IMF with elastic bands attached to an upper and lower Erich splint.
Arch bars have the advantage that, after a reasonable period of total immobilization, the mandible can be released, provided that the fracture line lies within the area of the teeth fixed to the arch bar and the fixation remains rigid. The arch bar is left in situ for a normal period of time.
Oral irrigation as well as chlorhexidine rinses and gel formulation applied to the gingiva are used to maintain the periodontum.
Arch bars may also be used for the fixation of subluxated teeth, once these teeth have been repositioned, with a similar technique to that described above. In these cases, it should be considered a second option in case a wire‐resin splint is not feasible.
6.2.3. Schuchardt’s wire, acrylic arch bar
Schuchardt (1956) and Schuchardt & Metz (1966) first described this concept. They designed an arch bar constructed from 2‐mm diameter aluminium brass alloy half‐round wire, which is wired to the teeth at the level of the mid‐crown and is maintained in this position by hooks, which fit into the space between the crowns of adjacent teeth. The hooks are made of 1.4‐mm wire and are soldered at right angles separated at equal intervals. These cross‐wires are positioned so that two‐thirds of the wire project to one side of the arch bar and one‐third projects to the other (Fig. 37).
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Figure 37. Schuchardt´s splint. A. Arch wire employed. B. Transverse positions of arch bar are bent to fit into the space between the crowns. C. Arch bar wired into position. D. Quick cold‐curing acrylic reinforces the splint. E. Excess wire hook removed. F. Intermaxillary fixation established.
The arch bar is conformed to the dental arch, after which the shorter ends of cross‐wires are turned over the occlusal surfaces of the teeth to prevent the arch bar from touching the gingival tissues (Fig. 38).
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Figure 38. Ladder metallic splint wired into position.
The arch bar is then ligated to the teeth with soft stainless steel wire. After cleaning and drying the teeth and arch bar, the bar and ligature wires are covered by self‐polymerising (cold‐cure) acrylic resin (Fig. 39).
Figure 39. Tie wires covered by self‐curing acrylic.
Once the resin has set, the clasps covering the occlusal surfaces are cut, leaving the vestibular portion of the cross wires to provide attachment for intermaxillary rubber bands or wires (Fig. 40).
Figure 40. The reference spikes have been removed and rigid IMF applied.
This arch bar is, therefore, prevented from lying against the gingival tissues, where areas of stagnation or pressure necrosis can occur if the stainless steel wires are loose. In addition, this acrylic arch bar is easier to clean than conventional arch bars.
To produce an accurate reduction of displaced bone fragments, the splint may either be wired to the teeth of the separate segments or it may be positioned in one piece, covered with acrylic, and then sectioned at the fracture site. After their accurate reduction, both segments are reunited by
means of a metal bar or stainless steel wire also covered by cold‐cure acrylic [Vita‐Zeta® (Vident)]
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Armamentarium
0.5‐ and 0.4‐mm stainless steel wire, stretched 10% to a 15‐cm length Schuchardt´s arch bar (Renfer Product Code: 7990200), Medicon Wire cutters and wiring forceps Luniatschek Cheek and tongue retractors Cold‐curing acrylic [Vita‐Zeta®(Vident)] Good illumination and suction device
Acrylic arch bars are simple to construct and save considerable time for the clinician and the maxillo‐facial technician; however, their removal is more difficult.
6.2.4. Dautrey arch bar
The Dautrey arch bar is made from soft stainless steel, 15 cm in length, which allows its installation from second molar to second molar along the dental arch.
Its main feature is the presence of a significant number of hooks. Depending on how these hooks are oriented during fixation, we may use the arch bar just for IMF; it can also serve as a method of fixation of dentoalveolar fractures or teeth avulsions.
Armamentarium
Dautrey arch bar (Medicon USA, code 68.04.93) 0.5‐ and 0.4‐mm stainless steel wire, stretched 10% to a 15‐cm length Wire cutters and wiring forceps Luniatschek Cheek and tongue retractors Good illumination and suction device
The arch bar is initially cut to a suitable length and afterwards bent to adapt to the curvature of the teeth.
The arch bar is fixed by passing 0.4‐mm (although some surgeons prefer 0.5‐mm wires, especially for the posterior segments) stainless steel wire ligatures around the neck of each available tooth (keep the wires below the greater circumference of the teeth by pressing the wire apically with the aid of an assistant holding an instrument like the Luniatchek while tightening the wire). The wires are twisted tightly to anchor the bar to the dental arch.
To avoid harmful wire ends, it is recommended to either place the ligatures in the interdental spaces or twist the ligatures several more times.
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Figure 41. Stabilization of dentoalveolar fractures by positioning the Dautrey arch bar upside down.
In cases of dentoalveolar fractures or dental avulsion, by inverting the arch bar´s orientation (Figs. 41‐43), effective stabilisation can be achieved. However, we remind the reader that for dental trauma, flexible fixation systems (e.g., resin wire) should be the first option.
Figure 42. Palatal luxation with partial avulsion of 21, 22. Figure 43. Teeth luxation reduced with Dautrey splint
6.2.5. Bern’s titanium arch bar
The arch bar is 14 cm in length, allowing for installation along the dental arch from second molar to second molar.
Armamentarium
Titanium arch bar (Medartis AG, Basel, Switzerland) 0.5‐ and 0.4‐mm stainless steel wire, stretched 10% to a 15‐cm length Wire cutters and wiring forceps Luniatschek Cheek and tongue retractors Good illumination and suction device
When a bar is needed only from first molar to first molar, the bar can easily be cut with a conventional wire cutter. Each arch bar is fitted with 21 hooks, each separated by 6 mm (Fig. 44). Each hook is approximately 4‐mm high, with a slight outward bend. It is designed for easy application and to prevent slippage of the wires or elastic bands
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Figure 44. Bern’s titanium arch bar.
The hooks are high enough to permit placement of more than one elastic band or wire on each hook. On the side opposite the hooks, the arch bar is cut in a wave pattern, allowing the wire ligature to fix the arch to each tooth (circumdental wire) and slide into the “bottom” of each wave. Consequently, this increases the stability of the fixed arch bar and allows the use of only a 3‐point fixation in each quadrant.
Finally, a longer pin in the middle of the arch bar on the side opposite the hooks defines the midline and temporarily holds the bar correctly in place while the first circumdental wires are placed.
Intraoperatively, the arch bar is bent to the correct shape, cut to the desired length, and ligated around the cervix of each tooth with a 0.4‐ to 0.5‐mm diameter, soft stainless steel wire ligature. Usually, for a fully dentate jaw, fixation to three teeth in each quadrant (one incisor, one canine or premolar, and one molar) is sufficient (Fig. 45).
Figure 45. Bern’s titanium arch bar, wired, and finished with rubber band IMF.
The titanium arch bar is easy and rapid to apply on the dental arches. It conforms well to the dental arch and allows excellent stability throughout the entire period of immobilisation. However, for many surgeons, the possible advantages of this type of arch bar do not outweigh the increased treatment cost.
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6.2.6. Baurmash’s arch bar
Armamentarium
Baurmash bonding bar (Walter Lorenz Surgical, Jacksonville, FL, USA) 0.5‐ and 0.4‐mm stainless steel wire, stretched 10% to a 15‐cm length Fluid light‐curing composite, bonding agent. Wire cutters and wiring forceps Luniatschek Cheek and tongue retractors Good illumination and suction device
Baurmash´s splinting technique uses an arch bar that is malleable enough to be contoured and adapted to the labial and buccal tooth surfaces, even by hand. By welding a thin strip of fine orthodontic wire mesh to the back of the arch bar, a suitable surface is provided for the use of direct bonding materials. Such arch bars are best made in short sections (Figs. 46 and 47) to ensure adequate adaptation to the teeth and avoid a single span crossing any fracture line.
Figure 46. Baurmash’ splint, fixed with direct bonding for short segment splinting.
After the bar is set in place (sometimes isolated wiring ligatures may be used to stabilise the bar), a light‐curing composite is added to fix the bar to the underlying teeth so that the bar becomes rigid. Mobile teeth, whether because of existing periodontal disease or as a consequence of trauma (e.g., teeth adjacent to the fracture site) will now be firmly set in place, enhancing the healing process.
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Figure 47. Rigid IMF over partial Baurmash splints.
For displaced fractures of the body and parasymphyseal areas, a bonding mesh‐backed arch bar is attached to the teeth on either side of the fracture line, including the teeth immediately adjacent to the fracture.
Once reduction is accomplished either with intermaxillary elastics alone or in combination with manual manipulation, the two bars will be solidly joined together by wiring from the lug of one bar closest to the fracture across the fracture to a similar lug on the adjacent bar. This will serve as a framework for the relatively thick composite cement that will run from the surface of one lug along the wire to the lug of the adjacent bar. In cases where there is no displacement, a bar can be bonded directly over the fracture and attached to at least two teeth, one on either side.
This method is particularly recommended in paediatric mandible fractures or in mandibular fractures when a rigid tension band is required.
6.3. Cap splints
Cap splints are designed to cover the occlusal surface and exposed parts of the teeth down to the gingival margins. These splints are indicated when a splint of unusual strength is required and can be either swaged or cast of German silver alloy and retained in place by cement. Satisfactory construction of such cap splints depends upon accurate dental casts and strict attention to the occlusion.
Cap splints are strong, resistant, well‐anchored, and particularly useful in fractures of the mandible when few teeth are present. One cannot, however, be certain of the articulation when the occlusal surfaces of the teeth are covered. When these cap splints are removed, occlusal disharmony must be corrected by grinding the cusps of the teeth. For this reason, some clinicians usually prefer to use appliances that do not extend over the occlusal surfaces of the teeth.
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6.3.1. Cast acrylic spints with cusps of the teeth exposed
The development of quick‐curing acrylic resins made possible the rapid fabrication of cast acrylic splints (Figs. 48A and B). However, their use in current practice is extremely limited.
These splints are useful for the treatment of dislocated teeth and alveolar segmental fractures. After reduction and realignment of the fragments, an impression of the dental arch is taken, and the splint is rapidly made and placed in position before the patient leaves the operating room. Greater accuracy may be achieved by constructing a wax pattern, which is then converted into acrylic.
Figure 48A and B. Acrylic splints, with uncovered occlusal surfaces for occlusal control.
Such splints have proven useful in fractures when the dentition is in poor condition. The retention of the splint may be reinforced by circummandibular wiring.
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6.3.2. Cast silver cap splints
Provided that an experienced maxillo‐facial technician and necessary laboratory facilities and time are available, cap splints are of great assistance for fractures where standing teeth are present on one or all of the separate fragments.
Cap splints have some advantages over arch bars. They:
• Reduce operative time • Prevent buccolingual rotation • Prevent superficial dental caries by avoiding plaque concentration • Can be placed under local anaesthetic
Their main disadvantage is that, depending upon the expertise of the technician, the preparation of cap splints may take between 4 and 8 hours.
The manufacturing of silver cap splints begins by obtaining accurate dental impressions.
Problems may be encountered in obtaining satisfactory impressions, but most issues can be overcome by a combination of operator dexterity and the use of modified metal or disposable impression trays whose flanges, particularly on the lingual side, are drastically reduced in depth. Additionally, disposable trays can be cut down to the size required to cover the respective teeth on the separate fragments. Continuous downward pressure on the posterior fragment by the clinician´s fingers will often relieve posterior gagging sufficiently to allow the insertion of the tray. This must be removed from the mouth by a combination of gentle upward leverage of the tray and downward pressure on the lower jaw. Such manipulation of impression trays will usually not cause much discomfort in early post‐accident stages.
The preferred material for impressions is alginate. This material is used at a consistency of a soft paste so that it spreads easily and flows into every available space. The use of perforated trays is recommended to avoid the impression being lifted off the tray. The impression must not be allowed to dry and should be cast immediately. Alginot (Kerr Co) is a silicone A impression material that behaves as an alginate, but does not shrink under dry conditions.
After cleaning all dental surfaces, impressions are taken of each separate tooth‐bearing fragment if it is impossible to obtain a satisfactory impression of all teeth in the jaw in a single tray. Any impression that loses its attachment to the tray should be recast.
Silver cap splints are manufactured using the lost wax technique. Alginate or silicon A impressions of the dental arches and an occlusal wax bite are taken and sent to the maxillo‐facial laboratory, together with indications regarding the sliding processes when required (e.g., in condylectomy and partial mandibulectomy, Figs. 49 and 50). Undercuts in the plaster models are covered with yellow wax or plaster, and the models are painted with a separating solution. A pink wax plate of 0.5‐mm thickness is used to model the body of the splint. The models are put into the articulator to identify and remove premature contacts.
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Figure 49. Silver cap splint with hooks and a detachable wing to guide articulation. Frontal view.
Figure 50. Silver cap splint with hooks and a detachable wing to guide articulation. Lateral view.
At the occlusal surface of each tooth, small perforations are made to enable checking of the splint’s fit and allow excess cement to extrude (Fig. 51). The wings are cut from a 1‐mm‐thick plate of nickel silver (an alloy containing 60% copper, 20% nickel, and 20% zinc). A hole of the size of a commercially available stainless steel screw is made in the wing, and the screw is placed into the wax wall. The wax is sprued with a treelike structure of wax that will eventually provide paths for molten casting material to flow in and for air to escape. Shafts of old acrylic drills are used for reinforcement.
The splint is poured in 900 silver (this alloy contains 90% silver and 10% copper). Wax hooks of 3‐mm width and 7‐mm length are soldered with silver. The splint is finished and polished, as are golden dental crowns. It is then sealed in place with glass ionomer cement. To ease its removal, the splint must be thin enough to allow its periphery to be peeled off the tooth so that the cement seal can be broken, and continuous metal struts that replace missing teeth must be thin enough to be bent or easily cut during splint removal.
When crowns are present, they should, if possible, be “passed by” using a lingual or palatal connecting bar between the individual sections. Once the splints have been completed, the technician must fill in all the screw holes and the undersurfaces of the hooks with softened, not melted, wax that can easily be removed later to prevent the entry of cement.
The splint design and positioning of the hooks depends upon the overjet and overbite. Approximately three hooks are required on each quadrant unless an alternative anchor for the tie
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wires is proposed, such as a locking plate or connecting bar. The hooks should be positioned to allow cross‐bracing in a zig‐zag pattern of the tie wires or elastic bands. If internal suspension is required, a loop or reversed hook is situated on the buccal aspect of the upper splint in the first molar region. It is very important to accurately design the position of the locking plates, because they may complicate the placement of a hook or interfere with the articulation of the buccal cusps of the teeth in the opposing jaw. The final position of multiple splints in each jaw, after fracture reduction, must also be considered so that the adjacent plates do not then contact each other and prevent an accurate reduction.
Damaged or grossly carious teeth that are to be retained, for example, to prevent displacement of the fracture, but that are liable to infection should be marked on the model and ideally left uncovered by the splint. Partially erupted wisdom teeth should also not be covered.
Figure 51. Perforation to allow excess cement to flow away and control seating and occlusion.
The contact points of teeth immediately adjacent to the fracture must be left uncovered so that an accurate reduction of the fracture will not be prevented by the otherwise intervening splint metal.
When possible, splints should be cemented to the teeth an hour or two before the operation so that the material can mature and harden before any stress is put upon it. Difficulty in seating the splint is usually caused by an undercut that has not been eliminated or a hole in the investment, producing a prominence in the casting. These must be reduced by a burr or stone until the splint fits accurately.
It is advisable to cement the lower splint in position first to prevent contamination of the lower teeth by excess cement from the upper jaw.
After applying the cement (ionomer glass cement, e.g., Ketac‐Cem™, 3M ESPE) to the splint at an adequate consistency, the splint is seated and pressed firmly to the teeth. Excess cement is wiped off by the assistant. The tips of the cusps of the teeth should then be visible through the holes drilled in the occlusal surface of the splint, which is held firmly in position for 2‐3 minutes until the cement has set.
If IMF is indicated, after removal of the throat pack, the lower jaw is immobilised to the upper jaw after fitting the teeth into the correct occlusion. The jaws are held in that position by means of elastic orthodontic bands or stainless steel wires, which are passed around the hooks in the opposing splints. Manual reduction of the displacement may first require distraction of the fragments to cause disimpaction. Once reduced, temporary stabilisation can be achieved by the placement of cross‐wires or elastic bands over the hooks on each side of the fracture line to exert compression on the bone ends.
Multiple fractures are more common in the lower jaw than in the upper jaw. A sectional splint does not possess the retentive properties of a complete unit and is easy to dislodge, even after the
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cement has completely hardened. In these cases, circumferential wires should be inserted to ensure the security of the mandibular sectional splints, and similarly, additional methods of fixation may be used in the upper jaw.
Figure 52. Silver cap splint demonstrated in a hemi‐mandibulectomy model.
Silver cap splints with sliding wings are useful after partial mandibulectomy for benign tumors in young patients. Occlusion and articulation are maintained during regeneration (Fig. 52).
To remove the splint, provided it is not too thick, an upper premolar pattern dental extraction forceps, aligned parallel to the occlusal plane, is used with one blade on the occlusal surface and the other on the cervical margin of the splint. A slow outward rotation of the forceps will usually break the bond between the cement and the splint in that area. This rotation is repeated elsewhere around the mouth as required until the splint can be lifted off.
TECHNIQUE OF LOCALIZATION
When fabricating the splints, the technician solders a long loop of soft metal wire to each locking plate, using high‐fusing solder. Each loop must be long enough to be bent so that it lies alongside the other in the required position, which is generally extraorally, allowing easier access and manipulation.
With the jaws immobilised and the fracture accurately reduced, the cheeks are retracted. The locking plates are screwed into position using mounting screws. The soft wire loops are then bent so that they lie in close proximity without direct contact with either themselves or the adjacent soft tissue. This is essential if distortion of the position of the locking plates is to be avoided after release from their bases and before the connecting bar is soldered into position.
The terminal part of the loops is immobilised using quick‐setting plaster in a small dental wax box. Once the plaster is set, the locking plates are unscrewed, and the whole assembly is removed with great care and given to the technician. If no distortion has occurred, the locking plates are in the exact relationship to each other that they are in the mouth.
The connecting bar of 3‐mm diameter half‐round German silver or cupro‐nickel bar is bent to conform with the dental arch so as to avoid the splints and hooks and remain clear of the alveolus. It is attached on the sulcus side of the locking plate by a low‐fusing solder so that the temperature required leaves the high‐fusing solder holding the wire loops intact. On completion, the localising
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wires are cut, and the solder is ground away. After polishing, the completed assembly of the two locking plates and connecting bar is returned to the surgeon, who screws it into position.
6.4. Gunningtype splints
In edentulous patients, IMF procedures are definitively more complex because of the absence of teeth to guide the occlusion or to serve as pillars to anchor the previously mentioned wires, arch bars, cap splints, and because of the loss of vertical dimension control.
It is recommended to approach the fracture directly and perform an open reduction with rigid internal fixation. However, in some circumstances, it may be useful to perform or maintain an IMF procedure (e.g., condylar fractures) to maintain the vertical dimension or to serve as a temporary method of immobilisation when surgery must be postponed.
In these cases, control is achieved by Gunning‐type splints retained by transalveolar and circumferential wiring or, occasionally, by other methods like IMF screws. It is therefore a form of indirect control of the bone fragments, transmitted through the mucoperiosteum.
There are several contraindications for the use of this method of IMF:
• Unfavorably displaced fractures lying outside the denture‐bearing areas • Projectile injuries involving grossly injured soft tissues and bone loss • Extreme jaw atrophy
Armamentarium
‘Gunnning‐type’ splints Sheets of black gutta‐percha or other lining materials Twelve or more 15–20‐cm lengths of prestretched stainless steel wire Wire cutters and wiring forceps Long and short curved Obwegesser‐type awls Cheek and tongue retractors Good illumination and suction device
Technique
Gunning splints may be constructed from:
• The patient´s existing dentures, suitably modified (remember that many edentulous patients have a usable, discarded set of dentures at home)
• Impressions • Models cast from the fitting surfaces of the patient´s dentures • Prefabricated Gunning‐type splints • Disposable, edentulous impressions trays without handles
The patient´s dentures are likely to have a reasonable vertical dimension and occlusion and thus are generally suitable to use. The incisors and canine teeth are removed from each denture together with the majority of the palate from the upper denture. Two or three hooks are fitted in each quadrant by adding cold‐cure acrylic to the labiobuccal surfaces of both dentures. The depth of the peripheral flange is reduced to allow for postoperative edema and, after being roughened, the fitting surfaces are lined with softened gutta‐percha. Small grooves may be cut on the occlusal surfaces of the denture to accommodate the peralveolar and circumferential wires. 61
When using impressions, the technician will need to correct major misalignments of the bone after sectioning of the models. Any minor discrepancy remaining will be compensated by the gutta‐percha lining. The vertical dimension is set at the time of the operation. To achieve this, a trough is made on the occlusal surface of the acrylic blocks, which occupy the molar areas of the lower splint. The maxillary blocks are ridged or grooved so that, opposed after reduction of the fracture, these fit into the softened gutta‐percha added to the trough. (Fig 53)
Figure 53. Troughs in the lower splint to adapt with the maxillary ridges.
Figure 54. Gunning splints with grooves in the occlusal surfaces.
It is advisable to ensure an adequate vertical relationship of the jaws, as this lessens the likelihood of respiratory obstruction, but this should not be carried to excess because it will cause trismus, pain from pressure on the mucosa, and disturbances of the bony alignment.
Once the splints are ready for the inset, the mouth is cleaned of any debris. Then the fracture is reduced, and any mucosal laceration is sutured. The splints are then immersed in hot water to soften the gutta‐percha, and each is placed in turn into the mouth to register an impression of the alveolar ridge in the reduced position. Extra lining material must be added to areas that are devoid of acrylic. If the bite is gagged, it will be necessary, in some instances, to grind down the acrylic ridge
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posteriorly if the depth of the gutta‐percha is inadequate to accommodate the extent of the closure required. The splint may then be removed and chilled in ice water.
Figure 55. Gunning splint with patient´s dentures, secured with IMF screws in a combined case of orthognathic andpPreprosthetic surgery in an edentulous patient. (Courtesy of Prof. M. Burgueño. Head of Department Oral and Maxillo‐Facial Surgery. University Hospital La Paz, Madrid).
Figure 56. Gunning splint with rigid wire IMF.
Figure 57. Gunning splint with rubber band IMF. Splints fixed with transalveolar and circummandibular wires.
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Afterwards, the upper splint is fixed to the maxilla by transalveolar wiring, pyriform aperture, circumzygomatic wire suspension or IMF screws (Figs. 55‐57), which are reviewed in Chapter 9.
The lower splint is secured to the mandible by circumferential wiring (Figs. 54 and 57. It is extremely important to insert the wires before placing the splint to avoid fracture malposition due to mandibular manipulation during the wiring.
After the wires have been placed, the mandibular splint is then immersed in very hot water and, after the reduction of the fractures has been checked once again, is placed in position in the mouth and held by an assistant while the surgeon secures it with circumferential wires. The bite, or occlusion, is checked to ensure that the acrylic ridges on the upper splint are accurately registered in the gutta‐percha lining the troughs in the blocks of the lower splint and that the vertical dimension of the bite is correct. The wires are cut, and their ends are bent.
After both splints have been positioned, the throat pack is removed, and the jaws are then placed in occlusion and immobilised by stainless steel wires or elastic bands, positioned around the hooks.
REFERENCES
• Wiilliams JL. Rowe and Williams´ Maxillofacial Injuries. Edinburgh: Churchill Livingston, 1994 • Kazanjian VH, Converse JM. Surgical Treatment of Facial Injuries (3rd Ed). Baltimore: The Williams and Wilkins
Company, 1972 • Gilmer TL. A case of a fracture of the lower jaw with remarks on treatment. Arch Dent 4:338, 1887 • Ivy RH. Observations of fractures of the mandible. JAMA 79:295, 1922 • Barker GR. A modified arch bar for immobilisation of the jaws following trauma and facial deformity surgery. Brit J
Oral Maxillofac Surg 24:143‐145, 1988 • Baurmash H, Farr D, Baumarsh M. Direct bonding of arch bars in the management of maxillomandibular injuries. J
Oral Maxillofac Surg 46:813‐816, 1988 • Leonard TS. The button wire as an aid to fixation. Brit J Oral Surg, 14:210‐212, 1977 • Obwegesser H. Über eine einefache Methode der freihändigen Drahtschienuug von Kieferbrüchen.
Österreichische, Zeitschrift Stomatologie 49:652‐654, 1952 • O´Kane M, King PA, Edmundson HD. Button Wires in the treatment of mandibular fractures. Int J Oral Maxillofac
Surg 15:422‐425, 1986 • Risdon F. The treatment of fractures of the jaw. Canad Med Assoc J 20:260‐271, 1929. • Robertson JH. Acrylic resin cap splints. Brit J Oral Surg 2:171‐174, 1965 • Schuchardt HJ. Injuries of the facial skeleton. In Modern Trends in Plastic Surgery 2. London: Butterworth, 1966 • Stout R. Manual of Standard Practice of Plastic and Maxillofacial Surgery. Philadelhia: W.B. Saunders, 1943 • Kupfer SR. Fracture of the maxillary alveolus. Oral Surg 7:830‐836, 1972 • Crawley WA, Azman P, Clark N, et al. The edentulous Le Fort fracture. J Craniofac Surg 8:298‐302, 1997 • Rinehart G. Maxillomandibular fixation with bone anchors and quick release ligatures. J Craniofac Surg 9:215‐219,
1998 • Buchbinder D. Treatment of fractures of the edentulous mandible, 1943 to 1993: a review of the literature. J Oral
Maxillofac Surg 51:1174‐1179, 1993 • Baudens JB. Fracture de la machoire inferiure. Bull Acad Med Paris 5:341, 1840 • Robert CA. Noveau procede de traitment des fractures de la portion alveolaire de la machoire inferiure. Bull Gen
Ther 42:22, 1852 • Lambotte A. Chirurgie operatorie des fractures. Paris: Masson & Cie, 1913 • Dingman RO, Natvig P. Surgery of facial fractures. Philadelphia, WB Saunders, 1964 • Pfeifer G. Kieferbruche im kindensalter und ihre Auswirkungen auf das Wachstum. Fortschr Kiefer Gesichtschir
27:497‐501, 1966 • Rowe NL. Fractures of the facial skeleton in children. J Oral Surg 26:505, 1968 • Rowe NL. Fractures of the jaws in children. J Oral Surg 27:497, 1969 • Rowe NL. Injuries to teeth and jaws. In Mustarde JC, ed: Plastic Surgery in Infancy and Childhood. Philadelphia,
WB Saunders, 1971 • Dawson RIG, Fordyce GL. Complex fractures of the middle third of the face and their early treatment. Br J Surg
41:254, 1953 • Ombredànne L. Precis clinique et opératoire de chirurgie infantile, 12ª ed. Paris: Masson, 1925 • Ombredánne L. Lósteosynthese temporarire chez les enfants. Presse Med 37: 845‐8, 1929 • Newland‐Pedley, P. Four cases of fractured inferior maxilla: Treatment. Br Med J 1:583‐584, 1889
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7. IMF screws
The major drawbacks of ligature wires and arch bars include the relatively long time to apply and remove them, and the risk of prick accidents to the surgeon performing the procedure. Finally, wires tightened during the application of arch bars around the teeth may cause ischemic necrosis of the mucosa and make it difficult for the patient to maintain gingival health (Wilson & Hohmann, 1976; Ayoub & Rowson, 2003).
To overcome these problems, Dal Pont developed an IMF procedure in which he used S‐shaped hooks inserted lateral to the pyriform aperture and at the inferior border of the mandible under general anaesthesia (Dal Pont, 1967). Otten (1981) improved this method using AO miniscrews inserted into the nasal spine and into the symphyseal region of the mandible. These screws were used to attach elastic bands or wires for IMF.
Figure 58. IMF screw (Srtyker). Figure 59. IMF screw (Medartis).
Current techniques using IMF screws (Figs. 58 and 59) recommend at least four self‐tapping/self‐drilling titanium screws inserted transmucosally, one for each quadrant.
There are several advantages to this procedure, compared to using arch bars:
• Insertion is easy and takes approximately 10 min, with significant intraoperative savings in both time and cost
• The screws are easy to remove, even without anesthesia (Arthur & Berardo, 1989; Busch, 1994; Karlis & Glickman, 1997; Jones, 1999)
• The risk of prick accidents is greatly reduced, which consequently decreases the risk of transmission of blood‐borne diseases
• The risks of damaging the dental papillae and periodontum are considerably reduced
• The teeth and dental prostheses are not subject to traction
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• Dental hygiene is easily maintained with IMF screws
However, there also major drawbacks that outweigh the potential benefits. According to Manson, these screws neither provide the stability and flexibility obtained from arch bars nor full IMF. A number of patients were thought to be in good occlusion using this technique when actually they had an open bite, were malreduced, and required osteotomy or fracture revision.
Additionally, there is a great risk of damaging dental roots while placing the screws (Key & Gibbons, 2001; Farr & Whear, 2002; Majumdar & Brook, 2002), especially in patients with dental crowding. Other complications reported include screw breakage (Holmes & Hutchinson, 2000; Coburn et al., 2002), loss of screws (Karlis & Glickman, 1997) or even iatrogenic damage to the inferior alveolar or mental nerve (Schneider et al., 2000; Vartanian & Alvi, 2000).
Finally, some authors (Jones, 1999; Schneider et al., 2000) have stated that IMF with screws does not allow postoperative, directional traction and cannot provide the ‘‘tension band’’ effect that can be achieved using arch bars.
Technique
Figure 60. Synthes set of IMF screws.
Pay attention to the canine root (the longest) and the mental nerve. Screws should be inserted 5‐mm inferior or superior and medial or lateral to the canine root, which may be palpated on the bone surface (Fig. 61A). Since the IMF Screws are self‐drilling it may not be necessary to incise and elevate the gingiva. Advance the screw making sure that the screw shoulder does not compress the mucosa. In dense cortical bone, it may be necessary to pre‐drill.
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Fig. 61A. Ideal piercing points for IMF screws (in relation with the canine root and the mental nerve). (Courtesy of Synthes, Ca Paoli)
In the mandible, insert the screw 5 mm inferior and medial or lateral to the canine root. If placing these screws inferior and lateral to the canine root in the mandible root, greater care must be taken to identify and avoid the mental nerve.
Figure 61B. Interdental IMF screw.
Four screws, 2.0‐mm diameter, 8‐10 mm in length, are inserted.
Figure 62. Rubber band IMF applied around the screw head.
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A 0.5‐mm diameter wire is either passed through the cross holes or alternatively wrapped around the screw heads. Alternatively, this can be accomplished using elastics.
Figure 63A. IMF wire passed through the hole in the screw neck.
Figure 63B. IMF screws should be avoided in patients with deciduous or mixed dentition for the great risk of damaging the tooth buds.
REFERENCES
• Arthur G, Berardo N: A simplified technique of maxillomandibular fixation. J Oral Maxillofac Surg 47: 1234, 1989 • Avery CME, Johnson PA: Surgical glove perforation and maxillofacial trauma: To plate or wire?. Br J Oral
Maxillofacial Surg 30: 31–35, 1992 • Ayoub AF, Rowson J: Comparative assessment of two methods used for interdental immobilization. J Cranio
Maxillofacial Surg 31: 159–161, 2003 • Borah G, DuffieldA: The fate of teeth transfixed by osteosynthesis screws. Plast Reconstr Surg 97: 726–729, 1996 • Dal Pont G: A new method of intermaxillary bone fixation. Trans Int Conf Oral Surg 325–329, 1967 • Otten JE: Modifizierte Methode zur intermaxillaren Immobilisation. Dtsch Zahna¨ rztl Z 36: 91–92, 1981 • Busch RF: Maxillomandibular fixation with intraoral cortical bone screws: a 2‐year experience. Laryngoscope 104:
1048–1050, 1994 • Gordon KF, Read JM, Anand VK: Results of intraoral cortical bone screw fixation technique for mandibular
fractures. Otolaryngol Head Neck Surg 113: 248–252, 1995 • Karlis V, Glickman R: An alternative to arch‐bar maxillomandibular fixation. Plast Reconstr Surg 99: 1758–1759,
1997
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• Wilson KS, Hohmann A: Dental anatomy and occlusion. Otolaryngol Clin North Am 9: 425–438, 1976 • Coburn DG, Kennedy DWG, Hodder SC: Complications with intermaxillary fixation screws in the management of
fractured mandibles. Br J Oral Maxillofac Surg 40: 241–243, 2002 • Holmes S, Hutchinson I: Letter: caution in use of bicortical intermaxillary fixation screws. Br J Oral Maxillofacial
Surg 38: 574, 2000 • Jones DC: The intermaxillary screw: a dedicated bicortical bone screw for temporary intermaxillary fixation. Br J
Oral Maxillofac Surg 37: 115–116, 1999 • Key S, Gibbons A: Re: care in the placement of bicortical intermaxillary fixation screws. Br J Oral Maxillofacial Surg
39: 484, 2001 • Schneider AM, David LR, DeFranzo J, Marks MW, Molnar JA, Argenta LC: Use of specialized bone screws for
intermaxillary fixation. Ann Plast Surg 44: 154–157, 2000 • Vartanian AJ, Alvi A: Bone–screw mandible fixation: an intraoperative alternative to arch bars. Otolaryngol
HeadNeck Surg 123: 718–721, 2000
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8. IMF techniques in children
In children it may be difficult to achieve stable IMF using standard wire techniques.
Before age 2 years, the deciduous teeth are not completely erupted. Children at this stage of
development are treated as though edentulous. An acrylic splint may be fixed in place with
circummandibular wires. If immobilization of the jaw is necessary, the splint may be fixed to both
occlusive surfaces with both circummandibular wires and wires through the pyriform aperture.
Once deciduous teeth are established, at about ages 2‐5 years, they may be used for fixation.
Although the deciduous teeth are conically shaped (rather than having a cervical waist), interdental
wiring may be used. Arch bars are somewhat more difficult to secure below the gum line. Redundant
support may be necessary. Mini‐arch bars attached with resin may be used to treat nondisplaced
fractures, again avoiding immobilization of the mandible.
A state of mixed dentition exists in children aged 6‐12 years. During this period, dental stability
is more precarious. Primary tooth roots are resorbing. Teeth often are loose or absent. In children
aged 5‐8 years, deciduous molars may be used for fixation. In children aged 7‐11 years, the primary
molars and incisors can be used to anchor fixation. When adequate dentition is not available for
fixation, Gunning splints may be used as in the younger patient. In children older than 9‐12 years,
standard intermaxillary fixation (IMF) with arch bars is possible because enough permanent dentition
has been established. Braces may also be used briefly for fixation.
IMF screws should not be used because of the great risk of damaging definitive teeth buds. Therefore, in pediatric patients, the most frequently used methods include the previously described bonding of orthodontic appliances or the use of custom‐made, wire‐composite splints.
Another technique that may be useful when bonding techniques are not available is Houpert’s procedure.
8.1. Houpert’s procedure
The operator should drill transfixion holes (in a vestibulo‐lingual direction) with a tiny round burr in the crown of the deciduous teeth away from the pulp and a safe distance from the occlusal surface.
A 0.2‐mm stainless steel wire impregnated in silver nitrate is introduced through the holes. Depending on the number of teeth used, either bimaxillary or monomaxillary fixation can be applied. Each hole should be filled with amalgam.
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A variation of this technique (Ginestet) allows placing an eyelet through each hole to fix both a vestibular and a lingual/palatal hard, 0.5‐mm stainless steel wire, with the possibility of a double splint device both in the vestibular and at the lingual/palatal aspect of the dental arcade.
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9. Wire suspension techniques
9.1. Circummandibular wiring
9.1.1. BlackIvy procedure
This technique, widely used prior to the ORIF techniques, was described to reduce and immobilize edentulous mandibular fragments. The intraoral device used to keep the reduction stable is the patient’s own acrylic denture or a custom‐made resin splint.
Armamentarium
0.5‐mm stainless steel wire, stretched 10% to a 40‐cm length Curved Obwegeser awl Nº 15 blade Wire cutters and wiring forceps Cheek and tongue retractors Good illumination and suction device
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Figure 64. Circunmandibular wiring.
Technique (Palfer‐Sollier – Fig. 64)
1. With a 15 blade, make a stab incision caudal to the mandibular branch of the facial nerve, at some distance from the fracture line. The Obwegeser awl is introduced and brought intraorally while maintaining good contact with the lingual periosteum.
2. Introduce a soft 0.5‐mm stainless steel wire into the awl’s opening, and bend it once around itself.
3. Use the awl to pull the wire around the body and pierce the vestibule to disconnect it from the awl.
4. Place as many of these ligatures as necessary to stabilize the fracture. 5. To fit the prosthesis, place some marks at the point where the ligatures are to be
tightened. 6. Make indentations with a burr to guide the ligatures. 7. Tighten the wires while keeping the fracture in proper reduction. Instead of twisting
both wire ends together for tightening, an eyelet can be made at both wire ends, and a second wire used, passing through the loops for tightening. In this way, fixation can be undone for assessment without removal of the circummandibular wire.
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9.1.2. T. Paoli procedure (transalveolar wiring)
This procedure is a modification of the Black‐Ivy technique for the maxilla in edentulous patients. Either the patient’s dental prosthesis or an acrylic splint with hooks or tubes to fit the holding wires can be used.
In case the patient’s prosthesis is used, part of the palatal acrylic should be removed on both sides and also on the anterior part.
With the prosthesis in place, a perforation is made just above the rim of the prosthesis through the maxillary bone, aimed at the palatal defect of the prosthesis.
An Obwegeser awl is gently introduced through the hole and, at the palatal side, a wire is threaded at the needle´s tip (Fig. 65).
The other end of the wire is tightened to the prosthesis through either an interdentate space or a sulcus made in the resin. Finally, both ends are twisted.
There should be two ligatures placed in the premolar region and, if necessary, a third ligature in the anterior area.
Figure 65. Transalveolar wiring procedure for fitting the Gunning splint to the maxillary edentulous ridge.
9.2. Pyriform aperture suspension
Armamentarium
Nº 15 blade Drill 0.5‐mm stainless steel wire, stretched 10% to a 40‐cm length Wire cutters and wiring forceps Cheek and tongue retractors Good illumination and suction device
Technique
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1. Under local or general anaesthesia, make a horizontal incision at the buccal sulcus, 2 cm in length.
2. Expose the inferior aspect of the pyriform rim. 3. With a periosteal elevator, gently detach the nasal mucosa a few millimeters from
the most anterior aspect of the nasal floor. 4. Drill a hole 3 to 4 mm away from the bony rim and protect at the same time with an
elevator (Fig. 66). 5. Introduce a soft stainless steel wire through the hole. 6. Twist the wire so that a loop emerges at the vestibule. 7. Close the mucosa with a resorbable suture. 8. Fix the loop to the device or wire to be suspended with a wire.
Figure 66. A pyriform aperture suspension cranial to a Le Fort I fracture. It may be tightened directly to the mandible, but preferably to a second wire loop that is fixed at two hooks on the mandibular arch bar.
9.3. Nasal spine suspension (OmbredanneBroadbent)
Armamentarium
Nº 15 blade Drill burr 0.5‐mm stainless steel wire, stretched 10% to a 40‐cm length Wire cutters and wiring forceps Cheek and tongue retractors Good illumination and suction device
Technique
1. Make a horizontal incision 3 cm in length at the buccal sulcus. 2. Perform subperiosteal degloving to expose the anterior nasal spine.
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3. Drill a horizontal or oblique hole, depending on the size of the spine (Fig. 67). 4. Complete the procedure as previously described for pyriform aperture suspension.
Figure 67. Nasal spine suspension combined with bilateral pyriform aperture suspensions.
9.4. Infraorbital rim suspension
Armamentarium
Nº 15 blade Drill burr 0.5‐mm stainless steel wire, stretched 10% to a 40‐cm length Wire cutters and wiring forceps Cheek and eyelid retractors Obwegeser awl Good illumination and suction device
Technique
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1. Make a subciliar or subtarsal incision at the inferior eyelid. 2. Expose the orbital rim, taking care of the infraorbital bundle. 3. Perform subperiosteal degloving, 1‐cm posteriorly. 4. While protecting the eyeball with a malleable retractor, drill an oblique hole in an
upward direction in the middle third of the orbital rim (Fig. 68). 5. Thread a stainless steel wire through the hole. 6. Tie both tips of the wire to a straight Reverdin needle or Obwegeser awl, and gently
push it in the subperiostal plane from the orbital rim towards the buccal vestibule. The mucosa should be pierced at the premolar region.
7. Tighten both tips, leaving a loop in the vestibule, which afterwards will hold the suspension wires.
8. If necessary, perform a similar procedure at the contralateral site.
Figure 68. Infraorbital rim suspension is shown.
9.5. Circumzygomatic suspension (Rowe Obwegeser)
Armamentarium
0.5‐mm stainless steel wire, stretched 10% to a 40‐cm length Wire cutters and wiring forceps Rowe or Obwegeser zygomatic awl Cheek and tongue retractors Good illumination and suction device
Technique (Figs. 69A and B, and 70)
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1) Introduce the awl extra‐orally at the junction of the frontal and temporal processes of the zygomatic bone.
2) Pierce the temporal fascia, keeping the point close to the deep surface of the bone.
3) Enter the upper buccal sulcus in the molar area.
4) Attach the wire to the awl.
5) Withdraw the awl without emerging from the skin, passing the point over the lateral aspect of the zygomatic arch.
6) Emerge through the original point of entry in the upper buccal sulcus.
7) Detach the wire and withdraw the awl.
Figure 69A. Passing the awl just in contact with the posterior surface of the zygomatic bone.
Figure 69B. After picking up the wire, it is withdrawn and with bone contact, again directed to the same incision in the oral vestibule, passing lateral to the molar bone
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Figure 70. Suspension wire fixed to the arch bar. Preferably, a second wire is used to fix it. When this one is cut, IMF can be released, but the suspension wire can still be used for a second IMF.
9.6. Supraorbital rim suspension
Armamentarium
0.5‐stainless steel wire, stretched 10% to a 40‐cm length 0.35‐stainless steel wire, stretched 10% to a 4‐cm length Wire cutters and wiring forceps Rowe or Obwegeser zygomatic awl Cheek and tongue retractors Good illumination and suction device
Technique (Fig. 71)
1) Make an incision in the lateral third of the eyebrow, or in the extension of a blepharoplasty incision.
2) Expose the fronto‐zygomatic suture.
3) Drill a hole 5 mm above the fronto‐zygomatic suture.
4) Pass a 0.5‐mm soft stainless steel wire through the hole.
5) Thread two ends of the 0.5‐mm wire through the eye of the zygomatic awl.
6) Pass the awl downward and forward behind the frontal process of the zygomatic bone, deep to the zygomatic arch.
7) Pierce the oral mucosa in the upper buccal sulcus of the molar area.
8) Release the wire from the awl and remove the awl.
9) Thread a 0.35‐mm soft stainless steel wire beneath the suspension wire in the supra‐orbital area. Pull out the wire, cut it supraorbitally, then pull it transorally.
ALTERNATIVE: Eyelet in suspension wire
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Figure 71. Supraorbital rim suspension.
9.7. Kufner suspension
A horizontal bur hole or a screw in the glabella region can fit a 0.5 mm wire suspending the central midface. The access is a median vertical incision, or a coronal approach in case of fractures of the frontobasis and Le Fort III.
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10. ORTHODONTIC AUXILIARY APPLIANCES FOR IMF IN ORTHOGNATHIC SURGERY
Correction of dento‐facial deformities often involves a combination of surgical and orthodontic treatment. Surgical procedures usually require fixing the maxilla and mandible together intraoperatively or over a period of time until healing is partially or completely achieved. This is generally accomplished by interconnecting the arch wire and/or the orthodontic appliances mounted on the teeth of the upper and lower jaws to obtain IMF, with the teeth directly in occlusion or on a splint.
Orthodontic auxiliary appliances used during IMF are passive elements that should provide anchorage to other active elements, such wire ties or elastics, and apply this force to the teeth and jaws. Depending on the place of force, the application can be classified into three types:
1. Teeth and bracket appliances 1.1. Bracket with hook 1.2. Power pin (arm)
2. Tie or ligature appliances 2.1. Tieback loops (Kobayashi)
3. Arch wire appliances 3.1. Soldered brass hooks 3.2. Pre‐posted arch wires 3.3. Crimpable/slidable hooks
10.1. Teeth and bracket types
10.1.1. Bracket with hook (Fig. 72)
The appliances mounted on the teeth generally include brackets mounted onto the teeth by a direct bonding procedure. Preferably, the brackets are of the edgewise type, having an edgewise or rectangular arch wire‐receiving slot. It is common to use ligature wires or elastics connected between the arch wires and/or the brackets to obtain IMF.
Threading ligature wires around the arch wires and/or the bracket is time‐consuming and difficult to achieve. Moreover, applying wires between brackets of the upper and lower arches requires those brackets to take the entire force of the interconnection, which sometimes causes failure of the connection of the bracket with a tooth, thereby impairing the integrity of the fixation between the jaws.
Modern appliances often have integral hooks incorporated into the orthodontic brackets, but attachments on the arch wire are preferred, particularly for segmental osteotomies.
Hooks for interarch elastics (auxiliary labial hooks) are routinely incorporated into the labial attachments for first and second molars in both arches. Although integral hooks are convenient at certain sages of treatment, they are full‐time food traps and should be used with caution in patients with questionable oral hygiene.
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Figure 72. Brackets with hooks on 3.5, 3.6, and 2.6. The other ball hooks are fixed on the arch wire and are crimpable hooks. Both 2.1 and 1.1 have a Kobayashi tie.
10.1.2. Power Pins (arms) (Fig. 73F and G)
A power pin is a traction hook that can be fitted in the bracket’s vertical slot. Made of soft stainless steel, it will normally be inserted from the gingival aspect and retained in the slot by bending the occlusally projecting tail 90 degrees. Strictly, this bend should be made in the opposite direction to the elastic pull to avoid a slackly turned pin doing a “U‐turn” and being pulled out of the slot by the elastic.
It can be seen in the side view that the head of the power pin is angled relative to the shaft. The pin should therefore be inserted with the head inclining away from the tooth or gingival margin, rather than towards it. Once fitted, the power pin can be left in place for as long as required; it does not interfere with arch checks. When its use is finished, its removal is easy by straightening the tail and cutting it with ligature cutters.
10.2.3. Buttons
Buttons are useful on buccal surfaces when lingual orthodontics is used and surgery indicated, and on palatal surfaces for cross‐elastics. Metallic buttons (Fig. 73A‐C and G) can be glued to enamel, applying a self‐etching primer (Transbond plus ‐ 3M Unitek) for 3‐4 seconds and then using a light‐curing adhesive paste (Transbond XT ‐ 3M Unitek). The paste sets in 6 seconds using a luminous curing light (Ortholux, 3M Unitek). Drying and rinsing are not required; hence, application during surgery requires minimal conditions.
Cheaper, equally quick, and esthetically pleasing appliances are mini‐mold buttons (Mini‐mold, G&H Wire Company), which can be made into many shapes by light‐curing composites in a transparent mold (Fig. 73D‐F).
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Figure 73A. Metallic buttons, some with ligature modules (light blue) to protect the cheek.
Figure 73B. Self‐etching primer (Transbond plus – 3M Unitek) with activator (violet). The small brush is out of the pack.
Figure 73C. Self‐etching primer (Transbond plus ‐3M Unitek), right bottom; light‐curing adhesive paste (Transbond XT ‐ 3M Unitek), left bottom; luminous curing light (Ortholux, 3M Unitek), upper; and metallic button, middle.
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Figure 73D. Mini‐mold kit with different mold shapes.
Figure 73E. Light‐curing resin is injected into the mold, which is placed on enamel prepared by self‐etching primer then light cured.
Figure 73F. Mini‐mold buttons (upper arch); power pins and hooks on the brackets, and a crimpable hook on the arch wire (lower arch).
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Figure 73G. Metallic buttons (upper arch), power pins, and hooks on brackets (lower arch)
10.2. Tie or ligature appliances
10.2.1. Kobayashi tie hooks Kobayashi tie Hooks available in .010-, .012-, and .014-mm wire, in long
and short versions.
Kobayashi ties are bent and slipped in a horizontal fashion over the bracket (Figs 74A-C).
Figure 74A. Kobayashi tie slipped horizontally over a bracket, after it is gently bent at its neck.
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Figure 74B. Twisted tie with loop directed cranially.
Figure 74C. The cut end is turned under the arch wire. The power pin is shown on 1.2.
10.3. Arch wire appliances
10.3.1 Soldered brass hook
Soldered brass hooks are the standard as a safe, secure hook for surgical wires and one of the traditional methods to perform IMF.
Brazing, defined as soldering over a temperature of 450°C, is the conventional method of joining hooks to the arch wire. Beside the problems of galvanic corrosion and biocompatibility, brazed joints have a low mechanical strength with high failure rates.
The strength of silver‐soldered joints used to fabricate space maintainers and orthodontic appliances is critical to their success. Broken appliances complicate orthodontic treatment, including the danger of soft tissue irritation, lost orthodontic anchorage, or aspiration of broken parts.
Another method employed for joining metal frameworks is laser welding. Recently, a new alternative with lower investment costs based on the technique of tungsten inert gas (TIG) welding was introduced in orthodontics.
The advantages of laser and TIG welding systems are that there is no solder and thus no galvanic corrosion in the joint, showing superior biocompatibility. However, these techniques require
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a small focus to perform the weld, and a stereomicroscope is desirable for efficiency, as well as an Argon‐shielding atmosphere to stop the oxidation process around the welding zone.
TIG and laser welding are solder‐free alternatives for orthodontic purposes and produce high mechanical stability.
Disadvantages
The use of soldered or welded wire spurs (e.g., T arms, hooks) involves their fixation to the arch wires prior to arch wire placement. This procedure requires considerable laboratory time and causes delay in completing the fixation process. Furthermore, the spurs are not movable once fastened to the arch wire, and in some cases where they might not be in the proper place, it is necessary to remove the arch wire and reposition the spurs.
Moreover, many times the arch wire becomes annealed or softened in the welding or soldering procedures, impairing the structural integrity of the connection of the spur to the wire as well as the rigidity of the wire. Moreover, in as much as the ends of the spurs are relatively sharp, they cause discomfort to patients, and during the fixation process, the surgeon's glove quite often snagged on the spurs and became damaged, which causes a delay in the process.
The main drawbacks are the required laboratory equipment, time of the procedure, potentially annealing of the arch wire, bracket slippage, gingival irritation, and a high risk of skin puncture during surgery.
10.3.2. Preposted arch wires
Pre‐posted wires overcome some of the disadvantages of soldered or welded hooks, such as required laboratory equipment and time of the procedure, but require a large inventory of stock, with obvious cost implications.
The spurs are not movable and in cases of inadequate placement, it is necessary to change the complete arch wire. Otherwise, this appliance has the same disadvantages as soldered hooks: the possibility of fracture with danger of lost surgical anchorage or aspiration of broken parts, gingival irritation, and high risk of skin puncture during surgery.
10.3.3. Crimpable hooks
The crimpable hook is commonly used for IMF during orthodontic and/or surgical treatment (Fig 72).
The hook may be slid onto the arch wire prior to placement or, where the split version is employed, affixed to the arch wire subsequent to placement. Indeed, no laboratory time is needed as the surgeon can easily apply the surgical hook to the arch wire as needed.
The crimpable hook used for surgical cases has a rectangular body with four connected walls for use on a rectangular wire. This hook may be closed and slid over the end of the arch wire or open
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(split) and applied to any part of the arch wire. Both types of crimpable hooks can be adjusted and positioned as needed along the arch wire.
In most instances, the appliances are mounted prior to placement of the arch wires in the slots of the brackets. In this instance, the appliance with the closed body would be employed. Where it is necessary to mount an appliance onto the arch wire subsequent to placement in the brackets, the open version is employed.
The appliance also includes an elongated bar or arm provided with a ball‐shaped free end, which is comfortable to the patient and avoids the existence of any sharp points upon which a surgeon's glove might snag.
Technique
Mount the crimpable hook on the arch wire between two adjacent brackets, prior to or subsequent to placement of the arch wire in the brackets. If mounted prior to placement, a closed crimpable hook can be used; if mounted subsequent to placement, a peripherally split crimpable hook can be used.
Use a standard pair of wire cutters, or other crimping device, for crimping the gingival side and the occlusal side of the tubular member on the arch wire.
Once the surgical ball hooks are in place, loop the ligature wires easily around the opposing appliances and twist the ends of the wires together to complete the IMF.
Thereafter, to release the fixation, remove the ligature wires; however, if some resilient fixation is desired, use rubber bands to interconnect the appliances.
Advantages
These hooks offer a number of advantages in patients undergoing orthodontic preparation for orthognathic surgery, permitting IMF to be applied, facilitating the postsurgical use of elastics:
1. Crimpable arch wire hooks allow quick and simple placement in the desired position with the arch wire in or out of the mouth.
2. The hooks provide an easy target for the surgeon to loop ligature wires over opposing or near opposing appliances on the upper and lower jaws.
3. They reduce the laboratory time needed to prepare the arch wires and have the potential to save costs in terms of both time and materials.
4. The hooks eliminate the need to heat the arch wire for mounting the appliance, thereby eliminating any injury to the structural integrity of the arch wire.
5. By virtue of the appliances being easily adjustable on the arch wire, slight vector forces may be established during IMF where such is deemed desirable.
6. Looping and tying the ligature wire around opposed surgical hooks on the upper and lower jaws dissipates the forces through the arch wire between two or three brackets, thereby reducing the possibility of a bracket from breaking its connection to a tooth.
7. When the fixation wires are removed, the same surgical hooks can also be used to anchor rubber bands, which continue the fixation (that allows the patient to freely open and close the mouth for eating purposes).
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8. The hook’s arm is provided with a ball‐shaped free end that eliminates sharp points, thereby increasing patient comfort and eliminating possible glove snags during the fixation process and delays in the process and risk of infection transmission.
Disadvantages
The major disadvantage of crimpable hooks is that the excessive force used to secure them can cause distortion or gabling of the arch wire as well as the introduction of unwanted force into the wire. If distortion of the arch wire occurs after impressions for model surgery and surgical splint construction, the teeth might move and not fit into the surgical splint at the time of surgery. This point underscores the need for integration of timing and techniques in combined surgical‐orthodontic treatments.
All known crimpable or collapsible hooks and/or stops suffer from a lack of adequate friction to keep them from sliding along the wire even when they are forcibly crimped. Arch wire hooks that slide when loaded during IMF are frustrating to surgeons but remain functional, because the sliding is generally limited to the interbracket width. However, arch wire hooks that spin around the arch wire cannot serve their functional purpose. In addition, poorly stabilized hook attachments pose a risk for aspiration or displacement from the wire into the surgical wound.
The superior performance of coated hooks is due to tungsten‐carbide coating, a hard, abrasive coating that creates strong frictional forces when challenged by a force. Once crimped into place, they resist sliding and twisting around softer, stainless steel arch wires.
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Acknowledgments
The following persons, associations and companies contributed to this manual.
Dentaal Tema en Rongé
Edurne Palacios, MD
Hans Hager
Informatics Department AZ St. Jan Brugge‐Oostende
José M. López‐Arcas MD, DDS, PhD
José Mª Garcia‐Rielo, MD, DDS
Julio Acero MD, DMD, PhD
Klaus W. Grätz MD, DMD
Labo Degraeve
Maurice Y. Mommaerts MD, DMD, PhD
Mölnlycke
Mozo Grau
The Royal Belgian Society of Stomatology, Oral and Maxillo‐Facial Surgery.
Vincent Dental Laboratorio Maxilofacial
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