deptt. of prosthodontics & crown & bridge

CONCEPTS OF OCCLUSION

SEMINAR

VIKAS AGGARWAL

INDEX

1. INTRODUCTION

2. NORMAL HUMAN DENTITION

3. THEORITICALLY IDEAL OCCLUSION

4. PHYSIOLOGICAL OCCLUSION

5. NON PHYSIOLOGICAL OCCLUSION

6. THERAPEUTIC OCCLUSION

7. DEVELOPMENT OF CONCEPT OF OCCLUSION

8. BILATERAL BALANCED OCCLUSION

9. UNILATERAL BALANCED OCCLUSION (GROUP FUNCTION)

10.LONG CENTRIC

11.PANKEY-MANN-SCHUYER PHILOSOPHY

12.MUTUALLY PROTECTED OCCLUSION

13.CANINE PROTECTED OCCLUSION

14.GENERAL OBJECTIVES OF ESTABLISHING OCCLUSAL

SCHEMES

15.OCCLUSAL CONSIDERATIONS IN FIXED PARTIAL DENTURE

16.OCCLUSAL CONSIDERATIONS IN REMOVABLE PARTIAL

DENTURE

17.OCCLUSAL CONSIDERATIONS IN SINGLE COMPLETE

DENTURE

18.OCCLUSAL CONSIDERATIONS IN IMPLANT SUPPORTED

PROSTHESIS

19.CONCLUSION:

INTRODUCTION

The study of occlusion and its relationship to the masticatory system has been a

topic of interest in dentistry since many years.

One of the chief aims of Preventive and Restorative dentistry has been to

maintain an occlusion that will function in harmony with the other components

of masticatory mechanism, thereby preserving their health at the same time

providing optimum, if not maximum masticatory function.

CONCEPTS APPLIED TO NATURAL DENTITION:

Although early anatomists such as Andreas Versalius and John Hunter described the static relationships of the natural dentition, these issues were not directly addressed until the dentists began to evolve the concepts related to the replacement of the natural dentition by artificial complete dentures.

Development of concept of occlusion--Three periods:

1. Fictional period (prior to 1900)

2. Hypothetical period (1900-1930)

3. Factual period (1930 to present)

EARLY CONCEPTS:

BONWILL:

Prior to Bonwill’s law, concepts of occlusion were based on the idea of a single, centrally located static hinge. This was embodied in the simple hinged articulators of the middle and late 19th century. Bonwill analyzed the mandible and described in terms of an equilateral triangle with 10cm sides connecting both condyles and the mesio-incisal angles of the mandibular central incisors.

His concept of geometric ideal was ‘ for the purpose of bringing into contact the largest amount of grinding surface of the bicuspids and molars, and , at the same time, to have the incisors all come into action during lateral movements’(1885). The resulting balanced occlusion would be for equalizing the action of muscles on both sides simultaneously, and getting the greatest amount of grinding surface at each movement which helps to equalize the pressure and force on both sides or parts of the dental arches.

Bonwill introduced equilateral anatomical articulator with 2 independent condylar elements. This instrument is considered the first example of the application of mathematical principles to the problems of occlusion (Butler and Zander, 1968). Bonwill’s instrument did not allow provision for condylar inclination. Walker in 1893 recognised this and designed an articulator with an adjustable condylar path mechanism and a complex extaoral tracing device to record the inclination of this path for each patient. This forerunner of later ‘gnathological’ concepts and instrumentation gave impetus to the idea that the creation of a balanced occlusion required the recording of the patient’s condylar inclination during protrusion and lateral excursion.

FERDINAND GRAF SPEE :

The concept of balanced occlusion itself is often credited to Ferdinand Graf Spee. He proposed that

1. The contacting occlusal surfaces of all natural mandibular teeth glide against those of maxillary teeth.

2. These area of contact lie on the same cylindrical surface , and3. The horizontal axis of the cylinders curvature pass through the middle of the medial

surface of the orbit behind the medial surface of the lacrimal duct.

Spee suggested that the occlusion functions like grinding millstones and that the mandibular movement occurs in circular paths just as the pendulum moves around an axis. The term curve of Spee derives from his observation that when viewed laterally, ‘the masticatory surfaces of the molars are aligned in an downward convex curve along the upper jaw and in an upward concave curve along the lower jaw’ (1890). He also believed that a posterior continuation of this curvature would pass along the anterior surface of the condyle, which also moves on a circular path with the same length of radius on the occlusal surfaces of the molars, that is, on the same cylindrical surface.

Spee concluded that, ‘ as forward and backward gliding of the mandible takes place in a path of circular motion, such displacement can occur over long distances without any need for the arches to separate from each other. Thus, masticatory efficiency is guaranteed. A separation of occlusal surface is only evitable in order to overcome the contact of strongly protruding upper and lower canineds. But this can also be eliminated by wear….this ought to be considered in construction of the dentures, not only to enable better mastication but also in order to avoid lever effects during chewing.

Thus, the balanced occlusion organization was born particularly for complete denture occlusion.

EDWARD HARTELY ANGLE(1900)

Gave his famous classification- Angle Class I , II, and III in 1900.

Drawback: it deals with the static occlusal relationships in centric occlusion. Thus angle’s concepts, although very valuable, did not directly deal with the issues of balanced occlusion, mutual protected occlusion or occlusal organization associated with eccentric positions of the mandible.

CHRISTENSEN(1902)

He was the first to describe an intraoral method for recording a static protrusive record to determine the condylar inclination, and he produced an adjustable condylar guide articulator, the rational articulator, to promote this technique. From his description came what Ulf Posselt coined “Christensen phenomenon”, or the posterior separation of the occlusal rims that occur when the mandible moves from a centric to a protrusive position.

ALFRED GYSI(1910)

He criticized the continued use of the simple up and down hinge articulator. He developed simpler methods to more accurately record the pathway of the condyle as it translates

anteriorly and inferiorly on the articular eminence. Gysi built several new articulators and extraoral tracings during this period.

He contended the condyle path does not form a straight as stated by Walker and Christensen , but follows a curved line or a S-shaped curve. He believed that mandibular movement is dependent on incisal as well as condylar inclination. Also, these points of rotation are not fixed points but results from diverse contraction of the masticatory muscles, and happens to coincide only now and then with the condyles.

GEORGE S MONSOON

Proposed Spherical theory, which was based, on the concept hat the mandibular teeth move over the occlusal surface of the maxillary teeth, as over the external surface of a segment of an 8 inch sphere, and the radius ( or the common center) of the sphere is located in the region of crista galli.

Monsoon disregarded the Bonwill horizontal excursion. However, he adapted the 10cm equilateral triangle that formed the basis of Bonwill theory, and added it to the occlusal curvature- fixed central axis of rotation concept of Spee. His conclusion produced the 10-cm radius sphere, a geometric embodiment of the function, form, and beauty of the masticatory system.

According to Monsoon, elongated teeth must be reduced in their length and teeth that have been in excessive function built up to their proper occlusion, bringing the occlusion of all teeth to conform to the surface of the sphere having proper interlocking cusps to maintain them in their alignment. The teeth are then ground into the full range of occlusion.

He did recognize two schools of thoughts for mandibular movement. The first believes that the shape and movement of the condyles govern the occlusion of the teeth, while the 2nd contends that the occlusion of the teeth is the dominant guiding factor, which determines the shape and movements of the condyles in the glenoid fossa. Monsoon followed the 2nd group as reflected in his articulators(maxillo-mandibular instrument) – he utilized a single midline pivot 10cm above the occlusal plane, and no condylar mechanism whatsoever.

These divergent theoretical approaches to understand and reproduce the mandibular movement shared one essential therapeutic objective: a completely balanced occlusion for full denture prosthesis. Denture stability was a paramount, and as a result the cross-arch, cross-tooth, and protrusive elements of balance were accepted.

CROSS ARCH BALANCE: simultaneous contact of working and non-working teeth.

CROSS TOOTH BALANCE: simultaneous contacting inclines of buccal-to-buccal and lingual-to-lingual cusps of working side teeth.

PROTRUSIVE BALANCE: provided simultaneously contacting inclines of both anterior and posterior teeth during protrusion.

RUPERT HALL(1914)

To explain his theory of mandibular movement, Hall envisioned that if two equilateral triangles ( constructed on Bonwill’s principles) were placed back to back, they would share a common base that represented the condylar axis. The vertex of the anterior triangle would be located at the incisor point, and the posterior vertex would be located at the external occipital protuberance.

Hall believed that an angle of 45 degrees would produce cusp of the highest efficiency in mastication. In natural teeth this is found predominantly in the maxillary first bicuspids. Hall chose the 45 degree angle as the generating angle for the cone.

Three occlusal concepts:

1.The Gnathological2.The Freedom-in-centric

3.European conceptual model

GNATHOLOGY:

HISTORY:

Dr. Beverly B. McCollum is considered the "Father of Gnathology." Dr. Harvey Stallard, an orthodontist, proposed the word Gnathology. It is derived from "Gnathos," meaning jaw and "ology," meaning study of, or knowledge of.

In 1924, Dr. McCollum discovered the first positive method of locating the Hinge Axis, a milestone in dental research. He founded the Gnathological Society in 1926. McCollum and the Gnathological Society's definition of Gnathology: Gnathology is the Science that treats the biologics of the masticating mechanisms; that is, the morphology, anatomy, histology, physiology, pathology and the therapeutics of the oral organ, especially the jaws and teeth and the vital relations of the organ to the rest of the body." McCollum and his associates developed their concept of occlusion on what was considered the immutable and ideal nature of the relationship between the condyle and the fossa, which in turn was responsible for guiding the mandible in its correct relationship to the maxilla. They believed that if an articulator could absolutely duplicate jaw relations and condylar movement, it would be possible to make the teeth that occlude ideally.

McCollum introduced the hinge axis locator, which could precisely pinpoint the transverse axis of condylar rotation. He embraced the idea of a completely balanced occlusion for the natural dentition that was totally consistent with his notion of an idealized biomechanical mechanism. The presumed objectives were

1.To maintain idealized occlusal contact throughout all excursions, coordinated in function with the stable condylar-fossa relationship, thereby eliminating potential tooth interferences during the ideal condyle positions and movements.

2. To distribute occlusal contacts among as many teeth as possible, resulting in reduced loading to the individual teeth and curtailment of periodontal breakdown.

In 1927, Harvey Stallard recognized that the teeth dictate the arc of closure and the occluded position of the mandible. If articulators were to be used to reveal mal-occluded teeth, then "interocclusal records" would be needed to mount the casts in the centric relation position. Proprioceptors from the teeth were dictating to the muscles, and this feedback had to be dealt with. Interocclusal registrations solved the problem. Since these registrations were taken at a slightly opened position, the Hinge Axis of the mandible must have been accurately located. In 1930, Dr. Charles Stuart and Dr. McCollum developed the first semi-adjustable articulator called the McCollum Gnathoscope.

By 1933, Stuart invented a frictionless jaw-writing device for recording mandibular movement with styli on plates outside the face. In 1934, with the aid of Dr. Stuart, McCollum produced the first mandibular movement recorder known as the McCollum Gnathograph.

It differed from today's recorder in that it anteriorly had a sagittal plate with a horizontal stylus. It would record the entire capacity of mandibular movements. These movements were later described by Posselt, as the "Envelope of Motion."

Dr. Stuart and Dr. Stallard worked together to teach "organic occlusion." They gave us the determinants of occlusal morphology and renewed an interest in Gnathological principals. Dr. Stuart often said that he had stolen the wax-addition technique from Everitt Payne and the cusp-fossa occlusion from the Good Lord to come up with Organic Occlusions. Peter K. Thomas, who taught the principles of Gnathology to study groups all over the world, was considered the "Ambassador of Excellent Dentistry."

THE PHILOSOPHY OF ARNE G. LAURITZEN

Direction of occlusal stresses-long axis of teeth. Centric relation=centric occlusion (condyles in uppermost and rearmost position)

Simultaneous occlusal loads fall on as great number of teeth. Optimal tooth-to –tooth occlusion should reach terminal hinge axis intercuspation

without interferences. Terminal hinge axis intercuspation should occur from an adequate interocclusal

freeway space. Lateral excursion may be free. Canine guided occlusion. Group contact between upper and lower anterior teeth during straight protrusive

movement.

DE AMICO ‘S CONCEPT

His conclusions had a direct impact on the thinking of the dentists with regard to concepts of occlusion. He developed the view that

1. The flattened edge-to-edge occlusion seen in aboriginal dentitions were due to excessive attrition and are abnormal.

2. A lateral ruminating type of mandibular function in humans is not typical.

3. Steeply cusp teeth are entirely appropriate

4. The maxillary incisors and canines are meant to exhibit overbite so as to disclude the posterior teeth during eccentric positions of mandible.

De Amico particularly emphasized the maxillary canines having the principal occlusal contact in lateral excursion and serving to guide the closing movement of the mandible in the centric occlusion. This idea has been termed CANINE PROTECTION.

NILES GUICHET AND GNATHOLOGY

Tried to explain the advantages of canine guidance by means of biomechanics.

Optimal occlusion (1966)

Canine guided occlusion- biomechanics Occlusion must be in harmony with the mandibular movements of each patient. Introduced modification of gnathological extra oral device of graphic registration

called Gnathograph to be used with a Pantograph, which were adjusted to Denar articulator.

In regard to vertical stresses, he incorporated the factors of an interocclusal relationship in order to reduce them.

In regard to horizontal stresses CO=CR. This eliminates the horizontal stress potential induced by patients when guiding their food in the retrusive range of the centric contacts. There is horizontal movement of the mandible from the maximal intercuspal position and teeth are capable of standing that horizontal stress in function.

He utilized D’ Amicos findings -canines –withstands eight times stresses than on the 2nd premolars.

Bennet movement: lateral shift increases as occlusion becomes tight.

THE VISION OF TRANSOGRAPHIC CONCEPT

PAGE HL being a layman conceived transographic theory.

Four principles:

1.Opening axis

2.Cranial plane

3.Bennett movement

4.Envelope of motion

1. Opening axis: 12º to 15º of rotation.

Transverse hinge axis –reproducible.

2.Cranial planes: No translatory condyles, so no practical support for horizontal plane.

3.Bennett movement: such a movement is because of mouth opening to 2 noncolinear axes, Page did not concede to the existence of the Bennett side shift.

4. In the discussions conceding the envelope of motion, when one takes the motions to a narrow functional terminal orbit, raised a great number of questions in the oral rehabilitation.

INFLUENCE OF PHYSICAL ANTHROPOLOGY

Many anthropological studies had great influence over occlusal concepts.

SPEE had emphasized the ruminant like grinding action of the human dentition, which strongly implied laterally directed excursive-incursive shearing movements of the mandible.

Examination of the flattened edge-to-edge occlusion and reverse curve of Wilson found in aboriginal societies seemed to bear witness to the importance of lateral component of the chewing cycle and to the maximum shearing of multiple inclined planes- an idea seemingly compatible with both the geometrical ideal and early gnathological concepts. In studies of the dentitions of Australian aborigines Begg (1964) noted severe interproximal and occlusal attrition and concluded that attritional process produced the only anatomical correct occlusion.

Jones observed in humans mastication is from lateral to medial and is unilateral, the teeth of opposite side being definitely not in contact.

OCCLUSAL CONCEPTS OF SCHUYLER

Like many gnathologists Clyde H Schuyler believed in harmony between centric relation and centric occlusion for natural dentition. He did not impose a set of rigid standards on the occlusion that, if lacking, was tantamount to pathology. This concept when applied to natural teeth was called FUNCTIONALISM.

Schuyler observed that all principles of occlusion pertaining to full denture prosthesis does not hold good for natural dentition. The term-balanced occlusion is most applicable to restorations supported by soft tissues. He believed there was a relationship between functioning occlusal inclines and potential stress to the periodontium, and his occlusal adjustment were to ameliorate these stresses. He suggested reducing the contact areas during maximum intercuspation and described a division of labor between inclines, cusp tips and occluding surfaces of teeth.

He favoured point contacts opposite flat planes during lateral excursions. In 1953, he stated, “in the natural dentition I fail to see the real value of contacts on the non-functioning side, as they do not reduce the application of stress being applied to the teeth on the working side, and their contact may be a contributing factor to traumatic injury.”

His observation effectively signaled the end of BALANCE as an acceptable treatment approach to the dentulous patient. Schuyler also emphasizes the importance of incisal guidance as the predominating factor determining posterior occlusal morphology. Although the muscles and TMJ’s control the direction of movement of the mandible when the dentition is out of occlusion.

When the opposing teeth of the natural dentition come into contact the guiding planes of the teeth immediately assume almost complete control of the direction and the extent of movement of the mandible. His concepts thus included the importance of canine guidance and canine –protected occlusion that was used for the desired relief of stress upon the balancing inclines of posterior teeth.

Anterior guidance – Purpose: permit a condylar motion without restrictions along with the prevention of posterior contacts, during lateral excursions

FREEDOM IN CENTRICAccording to Schuyler,

Freedom in centric is a maxillomandibular position where maximum intercuspation and centric relation coincide to a certain degree of freedom for eccentric excursions without the influence of occlusal inclines. (Figure)

Variation in centric relation recording – not a point – area in relation to horizontal plane.

Concepts that form this large occlusion group, freedom–in–centric, dealt initially with denture construction. Posselt was first to describe its principles.

Supporters of Functional occlusion developed the principles of this philosophy.

This concept basically deals with functional occlusion. Functional occlusion takes into consideration fundamentals of neurophysiological, psychological states, muscular functions, articular mechanisms and biomechanical knowledge. Rationale of this concept

1. To adapt itself to all maxillomandibular relationship patterns.

2. Fulfill the requirements of physiologic relations such as mandibular guidance, occlusal stability, mastication and swallowing.

According to this concept,

Maximum intercuspation and centric relation are coincident but flat areas on the depth of the fossae, on which opposing cusps occlude, will allow for a certain degree of freedom in both centric and eccentric movements without the guiding influences of occlusal inclines.

Vertical dimension of occlusion in maximum intercuspation and centric relation might be the same when all the interferences for closing in centric relation are eliminated.

STUART AND STALLARD CONCEPT

Stallard and Stuart: organic or organised occlusion.They noted that balanced occlusion in reconstructed natural dentitions leads to

1. Injudicious increase in occlusal vertical dimension to achieve balance. 2. Often led to instability of occlusion. 3. Frequently showed increased wear of teeth and restorations. 4. Provided poor group usage of teeth. 5. Extraordinary technical demands. 6. Esthetic character of the restored balanced occlusions, which often required

severe reduction of anterior overbite, was found to be far from adequate. Thus, some parallel ideas evolved in the concepts of both the gnathologists and the

functionalists, and both groups came to speak of the mutually protection concept of occlusion. This concept is based on the premise that the teeth should act as a specialized groups so that in centric or eccentric positions of the mandible certain teeth or groups of teeth are best able to withstand the occlusal loads and, in doing so, will protect other teeth or groups of teeth from unfavorable forces.

BEYRON’S OCCLUSAL CONCEPTS

Based on functional convenience and avoidance of discomfort. An optimal occlusion would be one that requires less muscular activity and is harmony with the neuromuscular system and TMJ guidance. Such occlusion might not be considered as static entity and might not be evaluated as having what he called ‘instantaneous occlusion’. Most physiological inter-relationship between morphology and function might be the most natural one. Beyron revealed that he majority of the subjects had anteroposterior slide, in the mandibular central position, in the range of 0 to 2 mm. Only 10% of them presented a coincidence of CO=CR. He also advocated freedom in centric concept & canine guided occlusion.

PANKEY MANN PHILOSOPHY

Monson’s sphere (occlusal line and plane) + Meyer’s concepts of a functionally generated path; some principles of occlusion and establishing Incisal guidance from Schuyler.

Pankey Mann Philosophy – oral rehabilitation

Objectives: - optimal health, masticatory efficiency, comfort and esthetics

Pankey Mann Schuyler concept (based on group function). Rationale about this group function is that a certain quantity of lateral stress on the posterior teeth might provide, during function and within a physiological tolerance, the necessary periodontal stimulus and might even spread the occlusal load to a certain number of teeth. The fundamental principles of this philosophy are as follows:

Stable and Static contacts - greatest number of teeth Long centric – Occlusal harmony with an anterior slide between centric relation and

maximum intercuspation (1mm) and a small amount of lateral freedom for accommodation of the Bennett movement on the horizontal plane.

Group function during lateral excursion (working side) Balancing side - No contacts Protrusion – Immediate disocclusion

DAWSON’S CONCEPT

Peter Dawson introduced Bimanual technique for the manipulation of the jaw in centric relation and for recording the border movements according to modification of functionally generated path technique. (In this colossal scheme, the maxillary teeth carve out a path in the wax placed on the lower colossal table. This is known as “functionally generated path”. Later, the wax containing this path is replaced with cast gold or cobalt-chromium alloy).

Group function during lateral excursion (working side) Balancing side - No contacts Protrusion – Immediate disocclusion

Theory of “Nutcracker”

When establishing an ideal occlusion, he assumed that he anterior guidance would have a key role. He defended the ideas that the anterior teeth are more capable of supporting stresses than are the posteriors because of the anteriors’ mechanical position in relation to the fulcrum(TMJ) and force( masticatory muscles), and because of higher density of bone surrounding the anteriors’ long roots, with a better crown root ratio. Dawson presented his theory of nutcracker. The farther the nut (anterior teeth) was from the fulcrum (condyles), the lesser would be the force exerted on the nut.

Making the nut as strong as possible by means of a correct interdental contact would make the role of protection of the anterior teeth better.

The condylar path is not supposed to dictate how the anterior guidance works, and so there is no advantage or necessity in trying to make the anterior guidance duplicate the condylar one. As a final consideration, the condyle path dictate where the external limits of the mandibular motion (envelope of motion) are and, in a free moving joint, the action of the muscles is responsible for both their functions and dysfunctions.

Nutcracker theory

GERBER’S CONDYLAR DISPLACEMENT THEORY

EUROPEAN CONCEPT

His theory is influenced from Gysi’s philosophy.“The normal or ideal occlusion proposed by Gerber was one in which the teeth would be in maximum intercuspation, with the condyles centered in the articular surfaces in the median and uppermost position. Any deviation related to this mandibular centralization constitutes a condylar displacement.”

CANINE PROTECTED OCCLUSION A form of mutually protected occlusion in which the vertical and horizontal overlap of the canine teeth disengage the posterior teeth in the excursive movements of the mandible (ANTERIOR PROTECTED ARTICULATION/ CUSPID PROTECTION).

The concept of the cuspid protection mechanism which is diametrically opposed to the balanced occlusal concept began in 1919 with the work of Nagao. This was reinforced by Shaw in 1924 and then gained most of it’s following after the extensive work of D’Amico in 1958. This theory suggests that the only tooth contact in all positions of the mandible except CR should be between maxillary cuspids and mandibular cuspids or first premolars. D’Amico also claimed that proprioceptors of the periodontal ligament associated with the canine teeth are far more responsive than those of any other teeth. Consequently the proprioceptors associated with the periodontal ligament of the canine teeth transmit desirable impulses to the muscles of mastication by way of central nervous system. Occlusal trauma to the canine teeth is thus prevented by the reduced muscular tension and

magnitude of the applied force.

Canine-guided occlusion

GROUP FUNCTION OCCLUSION

A form of mutually protected occlusion in which multiple contact relation between the maxillary and mandibular teeth in lateral movements on the working side whereby simultaneous contact of several teeth acts as a group to distribute occlusal forces (UNILATERAL BALANCED OCCLUSION).

SCHUYLER -1961.

Clinically, distinctions between canine protection and group function are often difficult to make, but the differences in the rationale underlying each is quite clear. The modern gnathological concept of canine protection is based on the assumption that ‘tooth blades and cusps are arranged for vertical chewing’ (Stuart and Stallard, 1960), and that cusp-fossa-groove position and form must be strictly integrated with the condylar and mandibular movements so that minimal tooth contacts occur during function. From this perspective, the canines help to prevent the lateral enmeshment of working side posterior teeth, which is considered not only superfluous, but potentially damaging as well.

Alexander P.C (1967) did clinical evaluation of the canine function theory and balanced occlusion theory. The evidence presented showed that canine teeth were incapable of supporting excessive functional forces. Vertical bone loss, with accompanying infrabony pocket formation occurred. He concluded from the periodontal point of view, the dentition should be treated according to the principles of balanced occlusion therapy.

Studies on the incidence of the canine protected occlusion have produced equivocal results. This is probably due to the use of different criteria, amounts of lateral excursion, age groups, cultures, and other variables among the studies. Collectively, however, the data tend to support the premise that the relative incidence of canine protection and group function is related to the age of the subject and the amount of attrition on the canines and other teeth, as well as on the basic structural features of occlusion.

Butler and Zander (1968) found a difference in the tooth contact pattern in two test subjects rehabilitated with two types of fixed partial dentures. Such observations indicate adaptability in the masticatory system to changes in the occlusal pattern.

MUTUALLY PROTECTED (Organized / Organic) OCCLUSION

An occlusal scheme in which the posterior teeth prevent excessive contact of the anterior teeth in maximum intercuspation, and the anterior teeth disengage the posterior teeth in all mandibular excursive movements.

STUART AND STALLARD 1960. - Organized disclusion.

Despite the continued dual perceptions of the canine protection versus group function, the development of mutual protection concept represent an embodiment of both gnathological and functionalist ideas, and is compatible with each. Functionalism’s most crucial contribution may have been the understanding of the variability and impreciseness of mandibular function and the intercuspation of the teeth. Gnathology has provided a biomechanical model and rationale for understanding function and occlusal morphology. Mutual protection in the broadest sense, can embrace both perspectives, and provides a basis for arranging teeth that takes into account these apparently contradictory approaches.

The aim of the organized occlusion is to relate the occlusal elements of the teeth, so that the teeth will be in harmony with the muscles and joints in function. The muscles and joints should determine the mandibular position of occlusion without tooth guidance. The ridges and groove directions of posterior teeth are determined as a result of the movements of the condyles.

The following organizational scheme and functional relationships of the natural dentition are derived from such a perspective:

1. In the intercuspal position, primary occlusal loading, axially directed, is absorbed by contact-supporting areas on posterior teeth only. Anterior teeth contact very lightly and should not bear these potentially heavy forces.

2. In protrusion, the overbite-overjet relations of the incisors produce an incisal guidance that is steep enough to cause disclusion of all posterior teeth.

3. In lateral excursion, the overbite-overjet relationship of the contacting teeth of the working side should be sufficiently steep to cause disclusion of all non-working side teeth. The question of whether the working side canine alone should be in contact (canine guided), whether the premolars should also be in contact, or whether all working side posterior teeth should be in contact (group function) is probably best determined on an individual case-by-case basis, depending on such clinical factors as preexisting relationships, root-crown ratio’s, and the degree of mobility or fremitus of the teeth involved.

OCCLUSION IN NATURAL DENTITION

Occlusion for the natural teeth is the integrated relationship of the teeth,

periodontium, temporomandibular joints and neuromusculature, not merely the

interdigitation of teeth.

THEORITICALLY IDEAL OCCLUSION / OPTIMUM OCCLUSION

It is preconceived view of structural and functional relationship. It does not

represent the norm in strict sense and only occasionally represents the

characteristics of a given individual. This concept is used as series of idealized

parameters against which variations may be compared.

According to this concept, occlusion and masticatory system should ideally be

such that: (Norman. D.Mohl 1988)

1. All components of masticatory system are present.

2. Classical anatomical relationship exist between maxillary and mandibular

teeth

3. In centric occlusion the supporting cusp of all posterior teeth should

occlude with marginal ridges except DB cusp of mandibular molars and

ML cusp of maxillary molars which occlude with central fossa of their

opposing tooth.

4. Dentition is in harmony with basal bone and with craniofacial structures.

5. Long axes of teeth are aligned so that functional occlusal forces act

through or close to these axes.

6. Periodontium is intact and there is no clinically detectable fremitus or

tooth mobility

7. The occlusion is stable that do not migrate other than slow physiological

compensatory movements.

8. Teeth do not exhibit attritional wear beyond what would be expected for

the age of individual.

9. Muscular contact position should be coincident with the intercuspation

position that is individual can voluntary control to close the mandible into

centric occlusion accurately and consistently with head erect.

10.Centric occlusion is in harmony with centric relation; that is, the two

positions are coincident, or centric occlusion is a short distance (within 1

mm) to the anterior of centric relation in the mid-sagittal plane.

11.During protrusion, the posterior teeth disclude so as not to interfere with

the ability of the opposing incisor teeth to occlude and function properly.

12.During lateral movements, the teeth on the nonworking side disclude so

as not to interfere with the ability of the opposing working side teeth to

contact and function properly.

13.During lateral movements, there is occlusal contact between the opposing

canines on the working side, either alone or together with one or more -

pair of adjacent posterior teeth.

14.A postural rest position that provides for an adequate interocclusal

distance.

15.All masticatory, deglutition, speech articulation, esthetic, and respiratory

requirements are met and are satisfactory to the patient.

16.Tonic activity of the masticatory muscles can be reduced to low levels at

times of repose.

17.Minimal parafunctional activity that is little phasic muscle activity is

present

18.Self-perpetuating structural and functional adaptation to ageing and to

altered conditions can be achieved.

19.Multi directional masticatory function can be accomplished satisfactorily

with wide variety of food.

20.No sign or symptom of pain or dysfunction from any component of

masticatory system can be detected.

21.The patient has an aura of unawareness of the occlusion and masticatory

system.

According to Dawson 1974 there are 5 criteria for optimal occlusion:

1. Stable stops on all teeth when condyles are in most superior posterior

position (centric relation).

2. An anterior guidance that is in harmony with the border movements of

the envelope of function.

3. Disclusion of all posterior teeth in protrusive movement.

4. Disclusion of all posterior teeth on balancing side.

5. Non-interference of all posterior teeth on working side with either the

lateral anterior guidance or the border movements of the condyles.

PHYSIOLOGICAL OCCLUSION

Physiologic occlusion, usually found in adults, deviates in one or more ways

from the theoretically ideal yet is well adapted to its particular environment, is

aesthetically satisfactory to the patient, and has no pathological manifestations

or dysfunctional problems. It represents a state of harmony, and does not require

therapeutic intervention.

In physiologic occlusion, either static or functional occlusal relationships may

be at variance from the classical characteristics of an occlusion. Although it

may be a malocclusion, it is a malocclusion in a state of health. It may

demonstrate maxillomandibular relationships different from theoretical criteria,

but no untoward effects are observed. Parafunctional activity may be present,

but all components of the masticatory system are responding well, and no pain

or dysfunctional signs or symptoms can be demonstrated.

The system has adapted and continues to adapt to the unique structural and

functional circumstances of that individual.

Criteria of physiological occlusion

1. Occlusal stability :

Teeth should stay in position without a tendency to extrude, drift, rotate, or

otherwise migrate within a dentition, The slow, compensatory, physiological

movement or adaptation that accompanies wear at contact areas in order to

maintain the continuity of the arch, or passive eruption to maintain occlusal

contact in the presence of a normal rate of attrition, are to be expected and are

acceptable. Migration beyond this (i.e., occlusal instability) is not acceptable.

2. Masticatory function

It should be satisfactory to the patient. This is a subjective assessment on the

part of the patient. If a patient can meet his or her own masticatory and dietary

needs, the situation is considered physiological.

3. Speech articulation

It should be acceptable to the patient. This is also a subjective assessment. An

impaired speech sound resulting from a malocclusion may be considered

physiological if the patient has no concern about this situation. An anterior open

bite accompanied by faulty sibilants, for example, need not be treated if the

patient’s assessment is neutral and no other unfavourable conditions exist.

4. Esthetic considerations

This is obviously a completely subjective assessment and must be left entirely

to the patient. For Example, a diastema between the maxillary central incisors

may be absolutely unacceptable to one patient and completely acceptable to

another.

5. Freedom from signs and symptoms

involving periodontal attachment apparatus that are related to functional

loading. Clinical detectable fremitus or mobility not directly attributable to

inflammatory process should be regarded as functional in nature, but if the

mobility is progressive it should not be considered physiological occlusion

6. Freedom from signs and conditions involving the teeth themselves

those are attributable to functional activity. Thus, a physiological occlusion

would preclude such conditions as excessive attritional patterns from para-

functional activities or from a very abrasive diet.

7. Freedom from signs and symptoms involving the temporomandibular joint

or the musculature associated with mandibular function

NON PHYSIOLOGICAL OCCLUSION

A non-physiologic occlusion is one in which there are signs or symptoms of

pathology, dysfunction, or inadequate adaptation of one or more components of

the masticatory system that can be attributed to faulty structural relationships or

to mandibular functional or parafunctional activity. The concept also includes

patient none acceptance of occlusally related speech articulation, or masticatory

parameters. A non-physiologic occlusion necessarily implies that the existing

maxillomandibular relationships are the cause of signs or symptoms.

In addition to the subjective criteria for treatment as expressed by the patient’s

concerns over esthetics, speech articulation, or masticatory function, there are

objective criteria. These are signs or symptoms of

1. Periodontal conditions attributable to functional loading,

2. Pathological conditions of the teeth that can be attributed to mandibular

functional or parafunctional activity.

3. Temporomandibular disorders.

THERAPEUTIC OCCLUSION

It is the one that has been modified by appropriate therapeutic modalities in

order to change non physiological occlusion to one that, at least fall within the

parameters of physiological occlusion. Examples include freedom in centric or

cusp to fossa posterior occlusal relationship instead of cusp to marginal ridge

relationship.

DEVELOPMENT OF CONCEPT OF OCCLUSION

Prior to Bonwill’s law, concepts of occlusion were based on the idea of a single,

centrally located static hinge.

This was embodied in the simple hinged articulators of the middle and late 19th

century. Bonwill (1885) analysed the mandible and described it in terms of an

equilateral triangle with 10cm sides connecting both condyles and the mesio-

incisal angles of the mandibular central incisors.

In 1890 Ferdinand Graf Spee proposed concept of balanced occlusion based on

his observation on natural teeth.

1926 McCollum and a group of dental colleagues founded Gnathological

society of California. They coined the term Ganathology which has been

defined as study of temporomandibular joints movements, their selective

measurement, reproduction and use as determinants in the diagnosis and

treatment of occlusion. McCollum embraced the idea of completely balanced

occlusion for natural dentition.

1929 Schuyler observed that balancing contact in natural dentition were more

destructive to periodontal structures. Thus he put forward the theory of

unilateral balanced occlusion.

Beyron in 1954 has listed characteristics of this type of occlusion.Weinberg in

1964 also supported this concept.Group function occlusion has broad support

from Mann and Pankey 1960, Ramjford and Ash 1966, Posselt 1968 observed

that this type of occlusion is commonly seen in natural dentition.

Schuyler in 1959 put forward the concept of long centric or freedom in centric.

D’Amico in 1961 gave the concept of Canine protected occlusion

Harvey and Stallard 1960 found anterior teeth protect posterior teeth and

posterior teeth protect anterior teeth. This concept of mutually protected

occlusion was based on this observation.

In 1967 term mutually protected occlusion was changed to Organic occlusion

by Stallard, Stuard and Thomas in 1967.

In 1974 Dawson stated that when canines cannot be used as guide for lateral

movement, posterior disclusion can be produced by anterior teeth. He called this

anterior group function.

Historically the study of occlusion and articulation has undergone an evolution

of concepts. These can be broadly classified as

1. Bilateral balanced occlusion

2. Unilateral balanced or group function

3. Mutually protected articulation

Bilateral balanced occlusion

The concept of balanced occlusion itself is often credited to Ferdinand Graf

Spee

•It was one of the earliest proposed theories -Bilateral Balanced Occlusion.

Although earlier applied to natural dentition ,it is now limited to complete

denture

•Bilateral, Simultaneous, Anterior and Posterior Occlusal Contact of Maxillary

and Mandibular Teeth in Centric and Eccentric Position

•When the principles of bilateral balanced occlusion were introduced in Fixed

Prosthodontics, there was a high rate of failure even with specific attention to

detail and use of sophisticated articulators. Failure was due to increased occlusal

wear, Increased/accelerated periodontal breakdown, TMJ and neuromuscular

disturbances

In 1935 ,Schuyler developed the first detailed technique for occlusal adjustment

based on careful grinding of specific occlusal inclines

He believed that there was relationship between functioning occlusal inclines

and potential stress to periodontium and occlusal adjustment was a way to

reduce this stress.

By 1953 he began to observe failure of natural dentition restored with balance.

He said that he failed to see the value of non-functional contacts as they did not

reduce the application of stress on the working side rather their contact may be

contributing factor for traumatic injury.

Stuart and Stallard (1960) noted that balanced occlusion in reconstructed natural

dentitions

1. 1 Often required injudicious increase in occlusal vertical dimension to

achieve balance.

2. Often led to instability of occlusion.

3. Frequently showed increased wear of teeth and restorations

4. Provided poor group usage of teeth.

5. Extraordinary technical demands

6. Esthetic character of the restored occlusions was not satisfactory.

SCHUYLER (1961) stated that an ideal occlusion has coincident Maximum

intercuspation position and Centric Relation position but this rarely occurs in

clinical situations.

2) UNILATERAL BALANCED OCCLUSION (GROUP FUNCTION)

Definition:-

Multiple contact relations between maxillary and mandibular teeth, in lateral

movements on the working side, whereby simultaneous contact of several teeth

acts as a group to distribute occlusal forces-GPT 8

In this type of occlusal arrangement the load is distributed among the

periodontal support of all posterior teeth on working side. This can be

advantageous if for instance periodontal support for canine is compromised.

While on the working side, occlusal load is distributed during excursive

movement, and the posterior teeth on the nonworking side do not contact. In the

protrusive movement, no posterior tooth contact occurs.

The most desirable group function consists of canine,premolar and mesiobuccal

cusp of first molar

Any laterotrusive contact more posterior than mesial portion of first molar are

not desirable because of the increased amount of force that can be created as the

contact gets closer to the fulcrum (TMJ).

Horizontal pressures during lateral movements are distributed to one half of the

arch on the working side.

The functionally generated path technique, originally described by Meyer

(1938) is used for producing restorations in unilateral balanced occlusion. It has

been adapted by Mann and Pankey (1960) for use in complete-mouth occlusal

reconstruction.

Advantages:

Group function of the teeth on the working side distributes the occlusal

load

The absence of contact on the nonworking side prevents those from

getting subjected to destructive, obliquely directed forces found in

nonworking interferences.

It also saves centric holding cusps that is mandibular buccal cusps and

maxillary palatal cusps from excessive wear

Group function was felt to be goal for occlusal adjustments and has easy

application

In the presence of anterior bone loss or missing canines, mouth should be

restored to group function

Long centric

As the concept of unilateral balance evolved, it was suggested that allowing

some freedom of movement in an anteroposterior direction is advantageous.

This concept is known as long centric

. Schuyler was one of the first to advocate such an occlusal arrangement. He

thought that it was important for the posterior teeth to be in harmonious gliding

contact when the mandible translates from centric relation forward to make

anterior tooth contact. Other have advocated long centric because centric

relation only rarely coincides with the maximum intercuspation position in

healthy natural dentitions.

However, its length is arbitrary. At given vertical dimensions, long centric

ranges from 0.5 to 1.5 mm in length have been advocated.

This theory presupposes that the condyles can translate horizontally in the

fossae over a commensurate trajectory before beginning to move downward. It

also necessitates a greater horizontal space between the maxillary and

mandibular anterior teeth (deeper lingual concavity), allowing horizontal

movement before posterior disocclusion (separation of opposing teeth during

eccentric movements of the mandible).

PANKEY-MANN-SCHUYER PHILOSOPHY

It used in complete occlusal rehabilitation

Objectives:

• Optimal Health

• Masticatory Efficiency

• Comfort

• Esthetics

Principles include

1. Static coordinated occlusal contact of maximum number of teeth when

mandible is in centric relation

2. An anterior guidance in harmony with lateral eccentric positions

3. In protrusion dïsclusion of posterior teeth

4. In lateral excursions ,dïsclusion of all non -working teeth

5. Group function of all working side inclines in lateral excursion

MUTUALLY PROTECTED OCCLUSION

It is an occlusal scheme in which the posterior teeth prevent excessive contact

of the anterior teeth in maximum intercuspation, and the anterior teeth

disengage the posterior teeth in all mandibular excursive movements.

Alternatively, an occlusal scheme in which the anterior teeth disengage the

posterior teeth in all mandibular excursive movements and the posterior teeth

prevent excessive contact of the anterior teeth in maximum intercuspation.

(Rosenstiel 4th ed)

Angelo D. Amico, (1958) using anthropologic and evolutionary studies

discarded the balanced occlusion and stressed on the function of the canines.

The ideas of Stuart, Stallard, Lucia, D’Amico (1963) and the members of the

gnathologic society lead to the development of the concept of organic occlusion

or mutually protected occlusion.

In this arrangement, centric relation coincides with the maximum intercuspation

position. The six anterior maxillary teeth, together with the six anterior

mandibular teeth, guide excursive movements of the mandible, and no posterior

occlusal contacts occur during any lateral or protrusive excursions.

The relationship of the anterior teeth, or anterior guidance, is critical to the

success of this occlusal scheme. The anterior teeth either contact lightly or are

very slightly out of contact (approximately 25 microns), relieving them of the

obliquely directed forces that would be the result of anterior tooth contact.

In a mutually protected articulation, the posterior teeth come into contact only

at the very end of each chewing stroke, minimizing horizontal loading on the

teeth. Concurrently, the posterior teeth act as stops for vertical closure when the

mandible returns to its maximum intercuspation position. Posterior cusps should

be sharp and should pass each other closely without contacting to maximize

occlusal function.

CANINE PROTECTED OCCLUSION

According GPT-8 the canine-protected occlusion is a form of mutually

protected occlusion in which vertical and horizontal overlap of canines

disengages posterior teeth in excursive movement of mandible.

This concept of occlusion is also known as canine guidance, canine disclusion

or canine rise from the Gnathology School of occlusion.

This theory suggests that the only tooth contact in all positions of the mandible

except CR should be between maxillary cuspids and mandibular cuspids. Thus

canine are called as NATURE’S STRESS BREAKER.

WHY CANINE

The canines have a good crown root ratio capable of tolerating high

occlusal forces.

Surrounded by dense compact bone which tolerates forces better.

Location is far from the TMJ thus receiving less stress.

It has many receptors in the periodontal ligament so it controls lateral

pressure by directing vertical masticatory movements.

The shape of the palatal surface of canine is concave and is suitable for

guiding lateral movements.

Canine protected Occlusion is an important concept, especially for people who

have

Excessive wear on their teeth,

Erosion of their roots,

Gingival recession,

And suffer from TMD (Temporomandibular joint dysfunction).

Limitations:-

• Controversy arises whether or not the canine should be the only

tooth to bear the pressures during lateral excursion

• Missing canine and prosthetic canine

• Periodontium is compromised.

• In Class III and cross-bite cases mutually protected occlusion is

contraindicated.

Dawson (1974) stated that,

• “When canines cannot be used ,lateral movements have

posterior dïsclusion guided by anterior teeth on the working

side, instead of canine alone”

• He called this “Anterior Group Function”

He defended the ideas that the anterior teeth are more capable of supporting

stresses than are the posteriors because

1) Of the anteriors’ mechanical position in relation to the fulcrum (TMJ) and

force( masticatory muscles)

2) With a better crown root ratio.

Stuart and Stallard (1961) modified features of mutually protected occlusion

and coined the term “ORGANIC OCCLUSION”in which Centric relation and

maximum intercuspal position coincide.

The aim of the Organized Occlusion is to relate the teeth to be in harmony with

the muscles and joints in function.

The muscles and joints should determine the mandibular position of occlusion

without tooth guidance.

Its features as described by THOMPSON (1967) are:

• CRP and MIP are coincident

• Posterior teeth are in a cusp fossa relation, one tooth to one tooth contact

• Each functional cusp contacts the occlusal fossa at three points

• In protrusion maxillary incisors guide the mandible and disocclude the

posteriors

• In lateral movements – lingual surface of maxillary canine glides along

the distal inclines of mandibular canine and mesial ridge of 1st premolar cusp.

GENERAL OBJECTIVES OF ESTABLISHING OCCLUSAL SCHEMES

In determining correct occlusal scheme for particular patient several factors

must be considered

1. Should the restoration be made in CO or CR

2. Will CO and CR be coincidental

3. What is correct lateral guidance

4. What is the character of occlusal contact

Centric Occlusion — Centric Relation

Maintain the patient’s centric occlusal position if a physiological state exists.

An anterior harmonious slide of 1.5mm or less, from centric relation to centric

occlusion with no lateral deviation is acceptable

When centric occlusion must be re-established, it should be coincidental with

centric relation.

Lateral guidance

1. Maintain the patient’s existing occlusal scheme in lateral excursion,

providing there are no signs of occlusal pathology. Both cuspid- protected and

group function occlusions are commonly found in natural physiologic dentitions

and should not be arbitrarily altered.

2. When re-establishing lateral guidance, cuspid protected occlusions is

preferable when the remaining natural cuspids are present and not periodontally

compromised. Cuspid guidance reduces occlusal wear and horizontal forces on

posterior teeth

3. Establish group function or unilateral- balanced occlusion for patients with

missing or periodontally compromised cuspids

Occlusal contacts:

1. Multiple equal intensity contacts on each tooth in CR at correct vertical.

2. Occlusal forces directed parallel to the long axis of each tooth.

3. Non-interference with any border path of the condyles or the anterior

guidance.

In determining the type of CR contacts there are further more choices to

be made:

1. Cusp to marginal ridge contact/ one tooth opposing two teeth.

2. Cusp to fossa contact/one tooth opposing one tooth.

Cusp to marginal ridge contact/ one tooth opposing two teeth.

The relation between the upper and lower teeth is such that one stamp cusp fits

in a fossa and another stamp cusp of the same tooth fits into the embrasure area

of two of the opposing teeth. This cusp-ridge arrangement is called a “tooth-to-

two-teeth” occlusion, or a“cusp-embrasure” occlusal pattern

Cusp to fossa contact/one tooth opposing one tooth.

In this scheme stamp cusps fit into fossae. The “cusp -fossa” relationship

normally produces an interdigitive relation of the cusps and fossae of one tooth

with the cusps and fossae of only one opposing tooth. This pattern may also be

called “tooth -to-one-tooth” occlusion

Advantages of Cusp-Fossa over Cusp-Marginal Ridge Pattern of occlusion:

A cusp fossa relationship produces an interlocking of the upper and lower teeth,

thus giving maximum support in centric occlusion. The forces are closer to the

long axis of each tooth, giving a more efficient chewing apparatus. The occlusal

forces are along the long axes of teeth thus less tipping. There is elimination of

food impaction between marginal ridges. The teeth are more stable, with more

stable occlusion.

.OCCLUSAL CONSIDERATIONS IN FIXED PARTIAL DENTURE

When majority of occlusal surfaces are restored with fixed restoration,

pre-existing centric occlusion cannot be preserved .therefore planned

restoration is restored in CO which is coincidental with CR(repeatable

position

Cusp fossa occlusion scheme is prescribed to enhance stability and reduce

food impaction

Occlusal tables are narrowed to maintain forces within the confines of

root system and to minimize non-working contact.

Lateral working position may be canine guided or group function, group

function is prescribed if canine is compromised and cannot support the

entire eccentric load.

Non-working contacts are eliminated in lateral excursion.

OCCLUSAL CONSIDERATIONS IN REMOVABLE PARTIAL

DENTURE

1. Simultaneous bilateral contacts of opposing posterior teeth must occur

in centric occlusion.

2. Occlusion for tooth-supported removable partial dentures may be

arranged similar to the occlusion seen in a harmonious natural

dentition.

3. Bilateral balanced occlusion in eccentric positions should be used

when a maxillary complete denture opposes the removable partial

denture. This is accomplished primarily to promote the stability of the

complete denture.

4. Working side contacts should be obtained for the mandibular distal

extension denture .These contacts should occur simultaneously with

working side contacts of the natural teeth to distribute the stress over

the greatest possible area. Masticatory function of the denture is

improved by such an arrangement.

5. Simultaneous working and balancing contacts should be formulated

for the maxillary bilateral distal extension removable partial denture

whenever possible.

6. Only working contacts need to be formulated for either the maxillary

or mandibular unilateral distal extension removable partial denture.

7. In the Kennedy Class IV removable partial denture configuration,

contact of opposing anterior teeth in the planned intercuspal position

is desired to prevent a continuous eruption of the opposing natural

incisors .Contact of the opposing anterior teeth in eccentric positions

can be developed to enhance incisive function but should be arranged

to permit balanced occlusion without excursive interferences.

8. Balanced contact of opposing posterior teeth in a straight forward

protrusive relationship and functional excursive positions is desired

only when an opposing complete denture or bilateral distal extension

maxillary removable partial denture is placed.

9. Whenever possible eccentric load should be borne by natural teeth

with disclusion of artificial teeth.

10. Maintain a narrow short occlusal table to minimize unfavourable

movement.

OCCLUSAL CONSIDERATIONS IN SINGLE COMPLETE DENTURE

The position of the remaining natural teeth in these examples may create

interferences in excursive movements of the single complete denture and create

instability that would not be a problem in a patient with natural dentition in both

arches and with anterior guidance. Correcting these interferences may be as

simple as an occlusal adjustment or as severe as extraction of the offending

tooth.

Presence of natural teeth in opposing arch increases the forces on complete

denture.Complete balanced occlusion should be given in such cases.

OCCLUSAL CONSIDERATIONS IN IMPLANT SUPPORTED

PROSTHESIS

The choice of an occlusal scheme for implant-supported prostheses is broad and

often controversial. Almost all concepts are based on those developed with

natural teeth, and are transposed to implant support systems with almost no

modification. No controlled clinical studies have been published comparing the

various implant occlusal theories.

The occlusion should distribute the forces evenly among the implants. The

occlusion chosen for implant-supported complete dentures or overdentures

should be a balanced occlusion ensuring that there is no interference with jaw

movements into eccentric positions. A lingualized occlusion provides an

excellent alternative to a fully balanced scheme. According to Carl E Misch a

medial positioned lingualized occlusion is a consistent approach for implant

occlusal schemes.

Canine guided occlusal scheme or group function can be given for single tooth

or implant supported FPD depending upon the patient occlusal status.

CONCLUSION:

Many occlusal schemes have been proposed over the years. Most schemes when

correctly used gives satisfactory results. The result is satisfactory, if the patient

gets better function, esthetics & comfort without any adverse changes in denture

foundation.

REFERENCES:

1. A Text book of occlusion Norman .D.Mohl 1988 1st edn

2. SHILLINGBURG- Fundamentals of Fixed Prosthodontics (3RD ED.)

1996

3. ROSENSTEIL-Contemporary Fixed Prosthodontics (4TH ED.)2006

4. OKESON-Management of Temporomandibular Disorders and

Occlusion (6TH ED) 2008

5. RAMJFORD & ASH- Textbook On Occlusion(2th Ed) 1979

6. PETER E.DAWSON- Evaluation,diagosis and Treatment of Occlusal

Problems(2ND ED) 1989

7. Carr, McGivney, Brown: McCracken’s Removable Partial

Prosthodontics 12TH ED 2011

8. Tylman Theory And Practice Of Fixed Prosthodontics 8th Ed 1989

9. Thorton .J.L (1990) Anterior guidance group function/canine

guidance. A literature review . J Prosthet Dent. 64, 479-481

10.Pasricha N, Sidana V, Bhasin S, Makkar M.(2012) Canine protected

occlusion. Indian J Oral Sci 3:13-8.