Comprehensive Retreatment of a 60yr Female: Skeletal Class II Division 2 Malocclusion, Severe Deepbite and Extraction Spaces

Drs. Shih IYH, Lin JJ, Roberts WE.

Abstract

History: A 60yr female presented with the chief compliant—unacceptable dentofacial esthetics. As an adolescent she had received full xed orthodontic treatment including extraction of four premolars.

Diagnosis: A relatively straight facial profile was associated with an excessive ANB angle (5.2 ̊), protrusive maxilla (83.3 ̊) and retrusive mandible (78.1 ̊). The occlusion was Class II Division 2 with an impinging deep bite (>9mm) and overjet of ~7mm in centric occlusion. First premolar extraction sites were open (2-3mm bilaterally) in the maxillary arch. The ABO discrepancy index (DI) was 15.

Etiology: The unfavorable longterm outcome was probably due to extraction of premolars in the lower arch, inadequate root alignment, and steepening of the plane of occlusion with extensive Class II elastics.

Objective: Optimize dentofacial esthetics consistent with an acceptable dental alignment.

Treatment: Open the vertical dimension of occlusion (VDO) ~8mm with bite turbos placed on the maxillary canines. Use a full xed, passive self-ligating (PSL) appliance to align both arches, close space, and maintain an ~5mm increase in the VDO. Correct black triangles in the maxillary anterior segment with enamel interproximal reduction (IPR) and space closure. Resolve the overjet and intermaxillary discrepancy with Class II elastics applied to the buccal or lingual of the U3s and L6s according to their relative axial inclinations. Utilize torquing auxiliaries to increase the axial inclination of the maxillary incisors. Retain with upper and lower Hawley to be worn full time for 6 mo, and nights only thereafter.

Outcomes: The mandibular plane rotated posteriorly (2.5 ̊), facial convexity increased, and lip protrusion decreased, but the Class II intermaxillary discrepancy increased. Residual Class II buccal segments resulted in an ABO cast-radiograph evaluation (CRE) of 30 points.

Conclusions: A pleasing dentofacial result was achieved by increasing the VDO and correcting the incisal relationships, but longterm retention with Hawley retainers is indicated. (J Digital Orthod 2018;51:4-17)

Key words: Class II, deepbite, Retreatment, Bite turbos, Torquing spring, IPR (interproximal reduction)
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Insignia^® System with Bone Screw Anchorage: Class I Crowded Malocclusion with Severe Maxillary Protrusion

Drs. Lee WH, Lee A, Chang CH, Roberts WE.

Abstract

History: A 16-year-old female presented with a chief complaint (CC) of crowded and protruded anterior teeth.

Diagnosis: Excessive lower facial height (LFH) was 59% of the total facial height (FH). A convex facial pattern (16 ̊) was associated with protrusion of the maxilla (SNA 89 ̊). Both lips were protrusive to the E-Line (3mm/5mm). Facial anomalies included an ANB discrepancy (8.5 ̊), lip incompetence (~5mm), and an occlusal plane canted inferiorly ~3 ̊ on the patient’s left side. Asymmetric Class III/I molar relationships were complicated by constricted arches, severe crowding in the anterior segments, and a 1.5mm midline discrepancy (mandible to the left). The Discrepancy index (DI) was 30.

Etiology: Constricted arches and excessive vertical dimension of occlusion (VDO) are usually associated with childhood developmental problems 1. inadequate loading of the jaws due to a relatively soft, refined diet, and 2. nocturnal airway de ciency. The latter is secondary to hypertrophic lymphatic tissue in the pharynx, that atrophies in late adolescence.

Treatment: An Insignia® system appliance with passive self-ligating brackets was designed for a treatment plan that included extraction of all four rst premolars to achieve speci c objectives. 1. Retract anterior segments to relieve crowding, reduce maxillary protrusion, and correct (prevent) excessive gingival exposure (gummy smile). 2. Enhance skeletal anchorage with bilateral infrazygomatic crest (IZC) extra-alveolar (E-A) bone screws (BSs). 3. Use bilateral maxillary incisor BSs to intrude and retract the upper anterior segment.

Outcomes:24 months of active treatment resulted in the desired outcome, as evidenced by a Cast-Radiograph Evaluation (CRE) of 24, and excellent dental esthetics (Pink & White) score of 0.

Conclusion: Complex malocclusions require a detailed mechanics plan involving supplemental anchorage, e.g. intermaxillary elastics and/or temporary anchorage devices (TADs). Prospective compensation for incisor retraction is an important prerequisite for producing an e cient xed appliance to optimize outcomes and minimize treatment time. (J Digital Orthod 2018;51:22-39)

Key words: Insignia^® system, passive self-ligating bracket, archwire sequence, custom bracket, IZC bone screws, miniscrew, bimaxillary protrusion, digital set-up, iatrogenic gummy smile, deepbite, Class II elastics, bite turbos, temporary anchorage devices, infrazygomatic crest, extra-alveolar, bone screws
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Early Treatment of a Class III Malocclusion with Severe Crowding and Deep Bite

Drs. Lin SL, Chang CH, Roberts WE.

Abstract

This report describes a conservative (non-extraction) early treatment for Class III malocclusion with anterior crossbite that began in the mixed dentition (9yr 6mo) and was nished in the early permanent dentition (12yr 8mo). Crowding was 6mm in the lower and 16mm in the upper arch, and there was no space for the unerupted maxillary canines. The probable etiology of the malocclusion was inadequate development of the maxillary arch, associated with ectopic eruption of the maxillary central incisors into an anterior crossbite that developed into a 100% deepbite. The ABO Discrepancy Index (DI) was 29. Early treatment for development of the maxillary arch was achieved with a 2x2 appliance, engaging the first molars and central incisors, supplemented with bite turbos on the lower incisors to open the bite, and open coil springs to tip the central incisors labially. After 23 months of treatment, the buccal segments were erupted and all maxillary teeth except the lateral incisors were bonded with a passive self-ligating (PSL) appliance. Space was opened with open coil springs for the blocked-out lateral incisors. At 28 months, buttons were bonded on the lateral incisors to apply archwire traction, and the lower arch was bonded from first molar to first molar (6-6) with PSL brackets. At 30 months, PSL brackets were also bonded on the lateral incisors and the maxillary arch was aligned. After 38 months of active treatment, 23 mo in mixed dentition and 15 mo in permanent dentition, an acceptable orthodontic alignment was achieved, as evidenced by a cast-radiograph evaluation (CRE) score of 25 points, but the second molars were not scored because they were not fully erupted. The superimposition of cephalometric tracings shows that the upper and lower incisors were tipped anteriorly, molars were extruded, and the mandibular plane angle was open about 3 ̊. Follow-up records 2 years after treatment revealed the correction was stable and late facial growth was within normal limits (WNL). Additional monitoring is indicated until the full permanent dentition (7- 7) is achieved. (J Digital Orthod 2018;51:44-61)

Key words: Early treatment, mixed dentition, Class III, severe crowding, deep bite, arch development
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Early Interceptive Treatment for Maxillary Lateral Incisor and Canine Transposition

Drs. Huang YH, Chang CH, Roberts WE.

Abstract

History: An 8yr-6mo girl was referred for orthodontic evaluation of bilateral blocked-out permanent canines that were labial to the roots of the lateral incisors. The patient and her family preferred an optimal correction without extracting permanent teeth.

Diagnosis: Facial convexity and the intermaxillary skeletal relationship were within normal limits (WNL), but the lower lip was retrusive. The crowns of the maxillary incisors were relatively well aligned, but roots of the laterals were displaced distally due to ectopic eruption of the canines on the labial surface. Molar relationships were end-on Class II bilaterally. Caries was noted on the mesial surface of the LL 2nd deciduous molar. The ABO Discrepancy Index (DI) was 29.

Etiology: Relatively small deciduous canines (Cs) were associated with deviated paths of eruption for the permanent canines (3s) resulting in ectopic eruption labial to the lateral incisor roots. Interceptive treatment was indicated to avoid transposition and periodontal problems.

Treatment Plan: Open space bilaterally in the maxillary canine areas. Extract the upper Cs and retract the ectopically erupted upper 3s into the expanded canine spaces. When the U3s are correctly positioned for eruption, bond a full xed appliance in both arches, and install bite turbos on the palatal surface of the upper central incisors. Correct interdigitation and overjet with intermaxillary elastics, then detail and nish. Remove appliances and retain with upper 2-2 and lower 3-3 xed lingual retainers.

Outcomes: Following 42 months of continuous mixed and permanent dentition treatment, this severe malocclusion (DI 29) was treated to an initial satisfactory result, as evidenced by an ABO Cast-Radiograph Evaluation (CRE) of 29. Three years later, eruption and settling of the 7s improved the outcome to excellent: CRE 19 points and the Pink & White dental esthetic score was 4.

Conclusions: A small upper C and lack of a canine eminence are indications to carefully monitor permanent canine development. If the path of eruption deviates to the mesial, extract the Cs and open space for the 3s. Expand the arch as needed and retract the erupting 3s to prevent transposition, periodontal problems, and the need to extract permanent teeth. (J Digital Orthod 2018;51:66-86)

Key words: Lateral incisor-canine transposition, ectopic canine eruption, interceptive treatment, Class II correction, non-extraction
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