Patient with oligodontia treated with a miniscrew for unilateral mesial movement of the maxillary molars and alignment of an impacted third molar Aya Maeda, a Yoko Sakoguchi, b and Shouichi Miyawaki c Kagoshima, Japan This report describes the treatment of a 20-year-old woman with a dental midline deviation and 7 congenitally missing premolars. She had retained a maxillary right deciduous canine and 4 deciduous second molars, and she had an impacted maxillary right third molar. The maxillary right deciduous second molar was extracted, and the space was nearly closed by mesial movement of the maxillary right molars using an edgewise appliance and a miniscrew for absolute anchorage. The miniscrew was removed, and the extraction space of the maxillary right deciduous canine was closed, correcting the dental midline deviation. After the mesial movement of the maxillary right molars, the impacted right third molar was aligned. To prevent root resorption, the retained left deciduous second molars were not aligned by the edgewise appliance. The occlusal contact area and the maximum occlusal force increased over the 2 years of retention. The miniscrew was useful for absolute anchorage for unilateral mesial movement of the maxillary molars and for the creation of eruption space and alignment of the impacted third molar in a patient with oligodontia. (Am J Orthod Dentofacial Orthop 2013;144:430-40) O ligodontia is the rare congenital absence of more than 6 permanent teeth, excluding the third molars. 1-5 The spaces created as a result of congenitally missing permanent teeth are often corrected using prosthetic appliances, tooth transplantations, or orthodontic treatment. 5-8 However, orthodontic treatment can be difficult in patients with oligodontia if the required distance for tooth movement is large and few teeth are available for anchorage. 4,5 Recently, miniscrews have been used for absolute anchorage in various types of procedures involving tooth movement. 4,5,8-15 In a patient with skeletal Class III and oligodontia, miniscrews and anchorage wires were used in the retromolar area for mesial movement of the mandibular molars. 4 In another patient with skeletal Class III, miniscrews were used to close the unilateral maxillary extraction spaces of the molars. 13 However, there have been few case reports in which miniscrews were used for absolute anchorage to move molars mesially. 4,13,14 Additionally, to our knowledge, there have been no case reports describing the use of miniscrews in the mesial movement of molars for alignment of an impacted third molar in a patient with a skeletal Class II relationship and oligodontia. This case report demonstrates successful treatment with miniscrews to enable unilateral mesial movement of the maxillary molars in a patient with oligodontia. DIAGNOSIS AND ETIOLOGY The patient was a 20-year-old woman with the chief complaint of maxillary and mandibular dental midline deviations to the left and crowded mandibular anterior teeth. Her facial profile was mildly convex, and she had a mildly gummy smile (Fig 1). She had a 5.0-mm overjet and a 4.0-mm overbite with a 1.5-mm mandibular arch length discrepancy. An asymmetrical relationship between the canine and the first molar, and dental midline deviations from the facial midline were observed. These abnormalities were due to oligodontia; 7 premo- lars were congenitally missing, and she had a maxillary From the Field of Developmental Medicine, Health Research Course, Department of Orthodontics, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan. a Assistant professor. b Postgraduate student. c Professor and department chair. All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest, and none were reported. Reprint requests to: Shouichi Miyawaki, Field of Developmental Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Department of Orthodontics, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan; e-mail, [email protected]. Submitted, revised and accepted, August 2012. 0889-5406/$36.00 Copyright Ó 2013 by the American Association of Orthodontists. http://dx.doi.org/10.1016/j.ajodo.2012.08.032 430 CASE REPORT
Transcript
CASE REPORT
Patient with oligodontia treated with a miniscrewfor unilateral mesial movement of the maxillarymolars and alignment of an impacted third molar
Aya Maeda,a Yoko Sakoguchi,b and Shouichi Miyawakic
This report describes the treatment of a 20-year-old woman with a dental midline deviation and 7 congenitallymissing premolars. She had retained a maxillary right deciduous canine and 4 deciduous second molars, andshe had an impacted maxillary right third molar. The maxillary right deciduous second molar was extracted,and the space was nearly closed by mesial movement of the maxillary right molars using an edgewise applianceand a miniscrew for absolute anchorage. The miniscrew was removed, and the extraction space of the maxillaryright deciduous canine was closed, correcting the dental midline deviation. After the mesial movement of themaxillary right molars, the impacted right third molar was aligned. To prevent root resorption, the retained leftdeciduous second molars were not aligned by the edgewise appliance. The occlusal contact area and themaximum occlusal force increased over the 2 years of retention. The miniscrew was useful for absoluteanchorage for unilateral mesial movement of the maxillary molars and for the creation of eruption space andalignment of the impacted third molar in a patient with oligodontia. (Am J Orthod Dentofacial Orthop2013;144:430-40)
Oligodontia is the rare congenital absence ofmore than 6 permanent teeth, excludingthe third molars.1-5 The spaces created as
a result of congenitally missing permanent teethare often corrected using prosthetic appliances,tooth transplantations, or orthodontic treatment.5-8
However, orthodontic treatment can be difficult inpatients with oligodontia if the required distance fortooth movement is large and few teeth are availablefor anchorage.4,5
Recently, miniscrews have been used for absoluteanchorage in various types of procedures involving toothmovement.4,5,8-15 In a patient with skeletal Class III andoligodontia, miniscrews and anchorage wires were used
the Field of Developmental Medicine, Health Research Course, Departmentthodontics, Graduate School of Medical and Dental Sciences, Kagoshimarsity, Kagoshima, Japan.tant professor.graduate student.ssor and department chair.thors have completed and submitted the ICMJE Form for Disclosure oftial Conflicts of Interest, and none were reported.t requests to: Shouichi Miyawaki, Field of Developmental Medicine, Healthrch Course, Graduate School of Medical and Dental Sciences, Departmentthodontics, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan; e-mail,[email protected], revised and accepted, August 2012.5406/$36.00ight � 2013 by the American Association of Orthodontists./dx.doi.org/10.1016/j.ajodo.2012.08.032
in the retromolar area for mesial movement of themandibular molars.4 In another patient with skeletalClass III, miniscrews were used to close the unilateralmaxillary extraction spaces of the molars.13 However,there have been few case reports in which miniscrewswere used for absolute anchorage to move molarsmesially.4,13,14 Additionally, to our knowledge, therehave been no case reports describing the use ofminiscrews in the mesial movement of molars foralignment of an impacted third molar in a patient witha skeletal Class II relationship and oligodontia. Thiscase report demonstrates successful treatment withminiscrews to enable unilateral mesial movement ofthe maxillary molars in a patient with oligodontia.
DIAGNOSIS AND ETIOLOGY
The patient was a 20-year-old woman with the chiefcomplaint of maxillary and mandibular dental midlinedeviations to the left and crowded mandibular anteriorteeth. Her facial profile was mildly convex, and she hada mildly gummy smile (Fig 1). She had a 5.0-mm overjetand a 4.0-mm overbite with a 1.5-mm mandibulararch length discrepancy. An asymmetrical relationshipbetween the canine and the first molar, and dentalmidline deviations from the facial midline were observed.These abnormalities were due to oligodontia; 7 premo-lars were congenitally missing, and she had a maxillary
Fig 1. Pretreatment facial photographs (age, 20 years 9 months).
Fig 2. Pretreatment intraoral photographs (age, 20 years 9 months).
Maeda, Sakoguchi, and Miyawaki 431
right deciduous canine and 4 deciduous second molars.The right canines had Class III occlusion, and the rightfirst molar had Class II occlusion. Both left canines andfirst molars showed Class I relationships (Figs 2 and 3).The panoramic radiograph indicated no root resorptionin the deciduous molars, and the maxillary right thirdmolar was impacted. Dental caries was noted in themaxillary right deciduous second molar (Figs 2 and 4).
Lateral cephalometric analysis indicated a skeletalClass II jaw-base relationship with an ANB angleof 6.5� and an average mandibular plane angle of32.0�. The lingual inclination of the maxillary centralincisor to the Frankfort plane angle was slightly
American Journal of Orthodontics and Dentofacial Orthoped
small (104.5�). The relationship of the mandibularcentral incisors to the Frankfort plane angle (52.0�) wasnormal (Fig 4, Table I).16 The frontal cephalometricanalysis showed that the mandible was not deviated,but the maxillary and mandibular dental midlines haddeviated by 3.0mm to the left of the facialmidline (Fig 4).
The maximum occlusal force and the occlusal contactarea were examined using an occlusal force recordingsystem (Dental Prescale & Occluzer; Fuji Film, Tokyo,Japan)17-19 and were found to be normal comparedwith those in normal subjects (Table II).17
This patient was diagnosed as having a malocclu-sion with oligodontia, maxillary and mandibular dental
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Fig 3. Pretreatment dental casts (age, 20 years 9 months).
Fig 4. Pretreatment radiographs (age, 20 years 9 months).
432 Maeda, Sakoguchi, and Miyawaki
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Linear (mm)U1 to APo 7.1 2.2 8.0 4.0L1 to APo 3.6 2.8 3.0 1.5Upperlip–E-line
�1 to �4 - 10.7 �1.0
Lowerlip–E-line
0 to 12 - 13.0 0
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midline deviations, mandibular anterior crowding, animpacted maxillary right third molar, a mildly gummysmile, and a skeletal Class II jaw-base relationship.
TREATMENT OBJECTIVES
Treatment was planned as follows: (1) extraction ofthe maxillary and mandibular right deciduous secondmolars; (2) mesial movement of the maxillary molarswith a miniscrew, mesial movement of the mandibularmolars, distal movement of the mandibular right firstpremolar, and retraction of the mandibular canine withpreadjusted edgewise appliances on the right side(Fig 5, A); (3) space closure to improve the mandibularmidline deviation; (4) bite opening after extraction ofthe maxillary right deciduous canine; (5) space closureto improve the maxillary midline deviation and mesialmovement of the maxillary molars after removing theminiscrew (Fig 5, B); (6) marsupialization and alignmentof the impacted maxillary right third molar; and (7)establishment of an acceptable occlusion (Fig 5, C).
TREATMENT ALTERNATIVES
Extractions of the maxillary deciduous canine andthe mandibular deciduous second molar on the rightside were needed to improve the deviation of themaxillary and mandibular dental midlines. We plannedto close the extraction space of the maxillary rightdeciduous second molar by mesial movement of themaxillary right molars. These molars were to be movedto align the impacted maxillary right third molar. Themovement of these molars was expected to occur overa long treatment period, involving large distances,
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unilateral posterior crossbite, and excessive retractionof the anterior teeth because of difficult anchorage.Therefore, a miniscrew was used for absolute anchorageto address these problems. Preservation of the maxillaryright deciduous second molar was considered because itwould avoid the need for absolute anchorage for a largeorthodontic tooth movement; however, this plan wouldnot allow for the alignment of the healthy maxillary rightthird molar instead of the maxillary right deciduoussecond molar with caries. The patient chose alignmentof the maxillary right third molar instead of preservationof the maxillary right deciduous second molar.
We considered extraction of the maxillary leftdeciduous and mandibular second molars and ortho-dontic closure of the extraction spaces. However, thistreatment plan would have caused an asymmetric dentalarch, with fewer posterior teeth on the left side becauseof the lack of a left premolar and a third molar.Therefore, this treatment alternative was rejected.
TREATMENT PROGRESS
The maxillary and mandibular right deciduoussecond molars were extracted, and alignment of theadjacent teeth and the mandibular second molar wasinitiated with a preadjusted edgewise appliance (0.0183 0.025 in). To ensure efficient mesial maxillary molarmovement, a miniscrew (diameter, 1.6 mm; length, 8.0mm; Pro-Seed, Tokyo, Japan) was placed in the maxil-lary alveolar buccal bone distal to the canine on the rightside. After the leveling and alignment of the teeth werecompleted, mesial movement of the maxillary right firstmolar was initiated with an elastomeric chain from theminiscrew to the maxillary right first molar with an initialforce of 2 N for 20 months (Fig 6,A and B). The mandib-ular extraction space was closed by mesial movement ofthe right first molar and distal movement of the rightfirst premolar by the elastomeric chain for 14 months.All teeth except the left deciduous second molars werethen aligned with a preadjusted edgewise appliance.After retraction of the mandibular canine for 7 months,the mandibular space was closed using loop mechanicsfor 3 months. After extraction of the right deciduouscanine, bite opening was initiated with a compensatorycurve in the maxillary archwire during the mesial move-ment of the maxillary right molars by the miniscrew. Theminiscrew was removed before retraction of themaxillary anterior teeth. The mesial movement ofthe maxillary right molars by a miniscrew was 7.5 mm.The space from the maxillary right molars to theanterior teeth was closed using an elastomeric chainfor 8 months. After the space closure, marsupializationand traction on the impacted maxillary right third molar
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Table II. Changes in maximum occlusal force and occlusal contact area
Fig 5. Schematics of the mesial movements of the maxil-lary right molars; arrows, direction of tooth movements;dotted lines, extracted teeth. A, mesial movement of themaxillary right molars with a miniscrew; B, retraction ofthe anterior teeth and traction and alignment of theimpacted right third molar; C, after tooth movements.
434 Maeda, Sakoguchi, and Miyawaki
were initiated (Fig 6, C). The orthodontic treatmentperiod was 40 months (Figs 7-10). After debonding,lingual fixed retainers were bonded, and Begg-type re-tainers were worn on both arches.
TREATMENT RESULTS
The patient had a balanced profile and goodocclusion. Normal overjet and overbite were achieved,
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and the maxillary and mandibular dental midlinescoincided with the facial midline (Figs 7-10). Themildly gummy smile was improved by the intrusion ofthe maxillary anterior teeth (Fig 7). The cephalometricsuperimpositions before and after treatment showedmesial movements of 9.0 and 4.5 mm of the maxillaryand mandibular molars, respectively, on the right side.The maxillary and mandibular central incisors hadretracted by 4.0 and 1.5 mm, respectively. The maxillarycentral incisor had intruded by 2.0 mm (Figs 10 and 11).The panoramic radiographs taken before and aftertreatment showed no marked apical root resorption. Inthe frontal cephalometric analysis, the maxillary andmandibular dental midlines coincided with the facialmidline (Figs 7 and 10). The occlusion and the facialprofile were almost stable after 2 years of retention(Figs 12-14).
Maximum occlusal force and occlusal contact areadecreased after treatment. However, these parametersincreased after the 2-year retention period (Table II).
DISCUSSION
We performed orthodontic treatment with a mini-screw for absolute anchorage to close the extractionspace of the deciduous molar and align the impactedmaxillary right third molar. After treatment, the patientshowed a good facial profile and a good occlusion.
Recently, miniscrews have been widely usedfor absolute anchorage during various typesof orthodontic tooth movement procedures.4,5,8-15
Orthodontic treatment with miniscrews in patientswith oligodontia was found to be particularlybeneficial because these patients have few teeth touse for absolute anchorage during orthodontic toothmovement.4,5 Miniscrews have been reported to beeffective for absolute anchorage in the mesialmovement of maxillary and mandibular molars; nolingual tipping of the incisors was observed inpatients with skeletal Class III and oligodontia orlarge extraction spaces.4,13,14 Our patient hadmaxillary and mandibular dental midline deviationsand a 5.0-mm overjet and was classified with a skeletalClass II relationship. We planned to close the 9.7-mmextraction space from the maxillary deciduous second
Journal of Orthodontics and Dentofacial Orthopedics
Fig 6. Treatment progress on the right side; white arrows, miniscrew. A, Start of mesial molarmovement with the miniscrew; B, 10 months later, continuation of mesial molar movement with theminiscrew; C, 33 months later, marsupialization and alignment of the impacted maxillary right thirdmolar after retraction of the anterior teeth.
Maeda, Sakoguchi, and Miyawaki 435
molar by mesial movement of the maxillary right mo-lars and the 7.5-mm extraction space from the maxil-lary deciduous canine by the retraction and rightdirectional movement of the anterior teeth. However,mesial movement of the molars and retraction of theanterior teeth by traction of each segment of anteriorteeth and molars was expected to cause unilateralposterior crossbite and excessive retraction of theanterior teeth because of the difficult anchorage.Therefore, we believed that our treatment plan wouldnot be successful without the use of a miniscrew toclose the extraction spaces because the required mesialmovement of the maxillary right molars was great. Weused a miniscrew for this purpose, and it resulted in thedesired 9.0-mm mesial movement of the maxillary rightmolars. The mesial movement of the maxillary rightmolars by a miniscrew and the anchorage of the ante-rior tooth retraction were 7.5 and 1.5 mm, respectively.
In this patient with oligodontia, 7 teeth were con-genitally missing, and 4 deciduous second molarsand 1 deciduous canine were retained. The maxillaryand mandibular right deciduous second molars were
American Journal of Orthodontics and Dentofacial Orthoped
extracted, and the extraction spaces were closed to alignthe maxillary right third molar and improve dentalmandibular midline deviation, mandibular anteriorcrowding, and molar and canine relationships. It wasexpected that the impacted third molar could survivebetter than the deciduous second molar with caries.20,21
Therefore, we chose to extract the maxillary rightdeciduous second molar.
We planned to retain the maxillary and mandibulardeciduous second molars on the left side. It has beenreported that deciduous molars have a good prognosisfor long-term survival and have been retained to theage of 51 years without caries or periodontal degenera-tion.20,21 Therefore, the maxillary and mandibular leftdeciduous second molars were retained in our patientto prevent the creation of a short dental arch withfew posterior teeth. To avoid root resorption, thepreadjusted edgewise appliance was not attached tothe deciduous molars.20,22 As a result, the roots of theretained deciduous molars were not resorbed. Webelieve that the deciduous second molars will beretained in the long term.
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Fig 7. Posttreatment facial photographs (age, 24 years 9 months).
Fig 8. Posttreatment intraoral photographs (age, 24 years 9 months).
436 Maeda, Sakoguchi, and Miyawaki
The maximum bite force correlates with the area ofocclusal contact.11,23-25 It is known that the occlusalcontact area and the occlusal force increase withretention after orthodontic treatment.26,27 Thesereports suggest that the interdigitation of the teethimproves after the removal of the orthodonticappliances because the teeth are allowed to settle.27 Inthis patient, the occlusal contact area and the maximumocclusal force increased over the 2 years of retention,reaching values greater than those before treatment,although the left deciduous second molars were not
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aligned by the preadjusted edgewise appliance. It is sug-gested that the interdigitation of the retained deciduousmolars without alignment by the preadjusted edgewiseappliance might improve during retention as well as af-ter removal of the orthodontic appliances. The treatmentresults show that stomatognathic functions in the pa-tient with oligodontia, such as occlusal force andocclusal contact area, might be increased with improve-ment of the malocclusion, including improvement in thedeciduous molars not aligned with a preadjusted edge-wise appliance.
Journal of Orthodontics and Dentofacial Orthopedics
Fig 9. Posttreatment dental casts (age, 24 years 9 months).
Fig 10. Posttreatment radiographs (age, 24 years 9 months).
Maeda, Sakoguchi, and Miyawaki 437
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Fig 11. Superimpositions of the cephalometric tracings at pretreatment (black line) and posttreatment(red line).A, Best fit on the anterior wall of sella turcica, the greater wings of the sphenoid, the cribriformplate, the orbital roofs, and the surface of the frontal bone; the maxillary and mandibular first molarsshow the right side; B, superimposition of the maxilla: best fit on the lingual curvature of the palateand the maxillary bony structures; C, superimposition of the mandible: best fit on the internal corticaloutline of the symphysis and the mandibular canal.
Fig 12. Facial photographs obtained 2 years posttreatment (age, 26 years 9 months).
438 Maeda, Sakoguchi, and Miyawaki
CONCLUSIONS
A miniscrew was useful as an absolute anchor forthe mesial movement of the maxillary right molarsand the alignment of an impacted maxillary right third
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molar in a patient with oligodontia. Additionally,improvement of the malocclusion, including improve-ment in the retained deciduous molars that were nottreated by the preadjusted edgewise appliance,
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Fig 13. Intraoral photographs obtained 2 years posttreatment (age, 26 years 9 months).
Fig 14. Dental casts obtained 2 years posttreatment (age, 26 years 9 months).
Maeda, Sakoguchi, and Miyawaki 439
prevented root resorption of the deciduous molars andincreased the occlusal force and occlusal contact areaduring retention.
American Journal of Orthodontics and Dentofacial Orthoped
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15. Shu R, Huang L, Bai D. Adult Class II Division 1 patient with severegummy smile treated with temporary anchorage devices. Am JOrthod Dentofacial Orthop 2011;140:97-105.
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19. Maeda A, Soejima K, Ogura M, Ohmure H, Sugihara K, Miyawaki S.Orthodontic treatment combined with mandibular distractionosteogenesis and changes in stomatognathic function. AngleOrthod 2008;78:1125-32.
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