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Dental Tribune Middle East & Africa

Dental Tribune Middle East & Africa Edition | May - June 2013 Fig.3,F) to allow perfect alignment and slight intrusion, aiming at facilitating ideal “stollerized” molar relationships.6 The fixed appliances were removed after 23 months. Treatment results Excellent occlusal results were established with coinciding midlines, perfect intercuspation, slightly overcorrected overbite, and even gingival margins on the central incisors (Fig. 3,E-G). Only a slight increase in intercanine distance was observed, while the interpremolar distance remained unchanged. Extraoral evaluation revealed well balanced facial proportions with harmonious lip curls and improved mento-labial fold (Fig. 3,A&C). Full smile was associated with minimal gingival display (Fig. 3,B&D). Cephalometric evaluation indicated ideal incisor positions and inclinations, with appropriate interincisal angle.Radiographic examination revealed adequate root parallelism and potential for 3rd molar eruption. Retention Follow-up evaluations demonstrate that the average orthodontic patient demonstrates relapse of alignment in the mandibular anterior segment long-term post-retention, with extreme responses ranging from 0 to almost 10 mm, regardless of initial irregularity and extraction approach, and despite excellent occlusal results with aims at avoiding undue expansion.7 About 50% of this variation can be explained by post- retention reduction in the intercanine distance.7 A proven approach to maintain the mandibular incisor alignment is to adapt a thick wire of size about 0.032” passively to the lingual surfaces of the mandibular anterior teeth, and to bond it only to the canines.8,9 Follow-up examinations demonstrate no risk of caries and periodontal disease associated with such retainers, despite a tendency for calculus build-up along the wire, and hardly any risk of distortion of the bonded segment. Another commonly used approach is to bond a flexible spiral wire of size about 0.019” to all six mandibular anterior teeth.9,10 However, although the reason is not fully understood, distortion of the bonded segment may not be unusual following long-term use of such retainers.10 In addition, individual bond failures may go prevent relapse of the deep bite. This retainer can be worn for a long period of time without risk of iatrogenic effects. References 1. Angle EH. Treatment of malocclusion of the teeth and fractures of the maxillae, Angle’s system, ed. 6, Philadelphia, SS White Dental Mfg Co, 1900. 2. Siegel MA. A matter of Class: Interpreting subdivision in a malocclusion. Am J Orthod Dentofacial Orthop 2002;122:582-6. 3. Tweed CH. Indications for the extraction of teeth in orthodontic procedure. Am J Orthod 1944;30:405-28 4. Loftus BP, Årtun J, Nicholls JI, Stoner JA, Alonzo TA. Evaluation of friction during sliding tooth movement in various bracket- archwire combinations. Am J Orthod Dentofacial Orthop 1999;116:336-45 5. Hershey HG, Houghton CW, Burstone CJ. Unilateral face-bows: A theoretical and laboratory analysis. Am J Orthod 1981;79:229-49 6. Stoller AE. The normal position of the maxillary first permanent molar. Am J Orthod 1954;40:259-71 7. Årtun J, Garol JD, Little RM: Long-term stability of mandibular incisors following successful treatment of Angle Class II, division 1 malocclusions. Angle Orthod 1996;66:229-38 8. Årtun J. Caries and periodontal reactions associated with long-term use of different types of bonded lingual retainers. Am J Orthod 1984 v.86 pp 112-8 9. Årtun J, Spadafora AT, Shapiro PA: A 3-year follow-up study of various types of orthodontic canine-to-canine retainers. Eur J Orthod 1997;19:501-9 10. Katsaros C, Livas C, Renkema A-M. Unexpected complications of bonded mandibular lingual retainers. Am J Orthod Dentofacial Orthop 2007;132:838-41 11. Fidler B, Årtun J, Joondeph DR, Little RM: Long-term stability of Angle Class II, Division 1 malocclusions with successful occlusal results at end of active treatment. Am J Orthod Dentofac Orthop 1995;107:276- 85 12. Bock N, Ruf S. Post-treatment occlusal changes in Class II division 2 subjects treated with the Herbst appliance. Eur J Orthod 2008;30:606-13 Figure legends Fig. 1: Pretreatment records demonstrating Class II, division 2 subdivision malocclusion associated with slightly increased ANB angle, a low mandibular planer angle, retroclined maxillary incisors, and retruded but normally inclined mandibular incisors (D). Fig. 2: Intraoral initial and progress photos demonstrating effect of unilateral HG for Class II correction (A,C) use of anterior bite plate during initial leveling of deep bite (E,F), and use of full size rectangulat wires following successful leveling (G,H). Fig. 3: Intraoral initial and progress photos in occlusal view demonstrating design of anterior bite plate used during initial leveling (C), and bonding of mandibular second molars (F). Fig. 4: Posttreatment records demonstrating excellent occlusal results with perfect intercuspation (E-G), slightly overcorrected overbite (F), well balanced facial proportions (A-D), ideal incisor positions and inclinations with appropriate interincisal angle (H), and adequate root parallelism (K). Fig. 5: Lateral cephalograms and study models in lateral and occlusal view made before (A,E,I) and after (B,F,J) treatment as well as at 6 months (C,G) and four years (D,H,K) follow-up of patient with stable correction of severe Class II overbite relationships, probably due to excellent, slightly overcorrected occlusal results at end of active treatment and use of fixed, mandibular canine-to-canine retainer to facilitate maintenance of mandibular incisor expansion and incisor contact. Note spontaneous alignment of blocked out maxillary second molars after maxillary first molar distalization during active treatment. unnoticed. Malalignment of the mandibular posterior teeth is rarely observed provided the pretreatment arch form is maintained. For this reason, the need for mandibular retention was limited to the anterior segment in this patient, and the strategy selected was to bond a thick spiral wire only to the canines (Fig. 4,I). Long-term follow-up examinations have demonstrated that the intercuspation is maintained in the average orthodontic patient following successful Class II correction.11 However, maintenance of overbite correction has been shown to represent a challenge.12 It may be speculated that a key to stability of deep bite correction is establishment of perfect Class I canine relationships, an acceptable interincisal angle, and maintenance of incisor contact through long-term use of a bonded canine- to-canine retainer in the mandible (Fig. 5). For those reasons, particular retention strategies in the maxilla, such as use of an anterior bite plate, were not advised for the present patient. Instead, a routine retention strategy with a vacuum formed retainer for full time wear the first six months and a gradual reduction in wear during the following year and a half was elected. Conclusions Adolescent patients with Angle Class II, division 2, subdivision malocclusions associated with minimal arch length deficiency in the mandible can be treated successfully with a non-extraction approach using a unilateral cervical headgear followed by multi-bonded fixed appliances. The class II correction is likely to be stable provided an ideal intercuspation is established, and maintenance of a fixed mandibular canine- to-canine retainer made of thick spiral wire bonded only to the canines is likely to maintain the inter-canine distance and the mandibular incisor position and indirectly www.idem-singapore.com THE BUSINESS OF DENTISTRY The Gateway to the Asia Pacific’s Dental Markets IDEM Singapore is a highly targeted trade exhibition and conference that offers exhibitors unrivalled prospects to meet and do business with the dental fraternity in the Asia Pacific region. With a powerful combination of an extensive international trade exhibition and a world-class scientific conference, IDEM Singapore has been a cornerstone event in the dental community calender since 2000. Capitalize on this unique opportunity and participate in this “must attend” event for every professional who is in the business of dentistry. 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