Retreatment of a Class II High Mandibular Plane Malocclusion Previously Treated with Extraction of Upper First Premolars
Shih YH, Lin JJ, Roberts WE.
An 18-year-5-month female presented with a Class II malocclusion, bimaxillary protrusion, convex profile, high mandibular plane angle (MPA) and chin retrusion. The Discrepancy Index (DI) was 25. History: full fixed orthodontics treatment with extraction of both upper first premolars at age 12 produced a good dental result, but the facial profile was disappointing, because of excessive lip protrusion. At the 5 year follow-up evaluation the patient requested retreatment. Intermaxillary posterior anchorage in two upper quadrants was established by extracting both lower second premolars and placing extra-alveolar (E-A) infrazygomatic crest (IZC) bone screws, bilaterally. After 25 months of active treatment, the buccal relationship was corrected to Class I and an excellent intermaxillary alignment was achieved, as evidenced by a score of 10 on the Cast-Radiograph Evaluation (CRE). Facial esthetics were significantly improved by reducing both lip protrusion and lower facial height, to establish lip competence with a balanced soft tissue profile. (Int J Orthod Implantol 2016;42:4-18)
Key words: Class II high angle, retreatment, TADs (temporary anchorage devices), IZC (infrazygomatic crest) miniscrews, autorotation of the mandible, vertical dimension of occlusion, bimaxillary protrusion
Acquired Malocclusion Due to Early Loss of Permanent First Molars: OBS-Anchored Orthodontics and Implant-Supported Prostheses
Chang MJ, Chang CH, Roberts WE.
A 27-year-old female presented with a complex malocclusion: 1. mandibular midline and occlusal plane deviated to the left, 2. excessive gingival display when smiling, 3. multiple missing teeth, 4. atrophic edentulous space in the upper left first premolar area, 5. deepbite, and 6. lingual crossbite from the maxillary right lateral incisor to the second premolar. All four first molars plus the upper left first premolar were missing, and the upper right first premolar was compromised. Etiology of the severe acquired malocclusion, Discrepancy Index (DI) 33, was attributed to an occlusal collapse when the deciduous second molars exfoliated. Treatment was rendered with a full fixed orthodontic appliance, utilizing passive self-ligating brackets and extra-alveolar (E-A) OrthoBoneScrew (OBS) anchorage. Orthodontic site development, followed by implant-supported prostheses restored the maxillary second premolar areas. A diode laser was used for a maxillary midline frenectomy, and selective gingivectomy to improve soft tissue contours. The interdisciplinary treatment for this severe malocclusion required 71 months. Outcome assessments were a Cast-Radiograph Evaluation (CRE) score of 25, Pink & White dental esthetic score of 5, and implant esthetic score of 0. (Int J Orthod Implantol 2016;42:20-41)
Key words: Self-ligating fixed appliance, lingual crossbite, bite turbos, extra-alveolar (E-A) OrthoBoneScrews (OBSs), gummy smile, gingivetomy, diode laser, occlusal canting, midline discrepancy, 2B-3D rule, Implant site development.
Conservative Treatment of Periodontally Compromised Class III Malocclusion Complicated by Early Loss of Lower First Molars
Yeh HY, Chang CH, Roberts WE.
A 29-year-old woman presented with a skeletal Class III malocclusion, anterior crossbite, atrophic extraction sites in the mandibular first molar areas, and periodontal pockets on the mesial aspect of the lower second molars. Probable etiology of the anterior crossbite was early loss of lower first molars. The severe malocclusion (Discrepancy Index 30) was corrected with the asymmetric extraction of maxillary second premolar and a passive self-ligating appliance. The anterior crossbite was resolved with anterior bite turbos and light force Class III elastics. Despite the periodontal problems, closing the mandibular spaces was deemed the best option for retracting the mandibular anterior segment to correct lower lip protrusion. Following 38 months of active treatment, dentofacial esthetics were improved and excellent dental alignment was achieved (Cast-Radiograph Evaluation 23). After treatment, the periodontally-compromised mandibular second molars had grade I mobility without pain, in addition to external root resorption. Follow-up records one year later documented the stability of the malocclusion correction. Periapical radiographs at 1 and 1.5yr after treatment revealed improvement in the osseous support, and an arrest of root resorption for the right mandibular second molar, but the mesial root of the contralateral second molar was affected by internal and external root resorption. Both compromised lower second molars served as adequate anchorage and subsequently functioned normally. Although one or both of the compromised molars may be lost in the future, retaining them for as long as possible was the optimal treatment plan. (Int J Orthod Implantol 2016;42:44-59)
Key words: Class III anterior cross-bite malocclusion, atrophic extraction site, external root resorption, self-ligating appliance
Extraction Treatment for an Asymmetric Class III/I Malocclusion with Blocked-Out Canine, Bimaxillary Crowding, Midline Deviation
Lee A, Chang CH, Roberts WE.
A 20y2m female presented for orthodontic consultation to evaluate severe crowding, ectopic eruption of the upper right canine, a canted occlusal plane, and protrusive lips. Clinical examination revealed a Class III/I asymmetric malocclusion with severe crowding, narrow arches, a steep mandibular plane (SN-MP 41°), and flared lower incisors (L1 to MP 108°). The Discrepancy Index (DI) for this challenging malocclusion was 32. All four first premolars were extracted and the malocclusion was treated with passive self-ligating brackets. The pleasing result is documented by a Cast Radiograph Evaluation (CRE) of 24 and a Pink & White (P&W) dental aesthetic score of 4. Follow-up records two years later revealed a stable result. (Int J Orthod Implantol 2016;42:64-80)
Key words: Blocked out canine, severe crowding, midline deviation, asymmetric Class III malocclusion, passive self-ligating appliance, posterior crossbite
Cleidocranial Dysplasia: Surgical and Orthodontic Management of Multiple Impactions in the Mandible
Hsu E, Chang CH, Roberts WE.
A 24-year-old female presented with the distinctive dentofacial features of cleidocranial dysplasia (CCD) including multiple supernumerary and permanent impacted teeth. Cone beam computed tomography (CBCT) was essential to accurately identify and plan the surgical recovery of the compromised permanent teeth. All obstacles in the paths of eruption were surgically removed, and OrthoBoneScrews (OBSs) with 3D lever arms provided the traction mechanics. Patients with CCD are complex problems, requiring carefully coordinated interdisciplinary care. (Int J Orthod Implantol 2016;42:84-96)
Key words:supernumerary teeth, impaction, CBCT, OrthoBoneScrews, 3D lever arm, cleidocranial dysplasia
Clinical tips for stress-free 2X4 Treatment
Hsu YL, Chang CH, Roberts WE.
Early orthodontic treatment is commonly requested in pediatric dentistry (pedodontic) practices. A conventional 2x4 fixed appliance (two molars and four incisors) is one of the most frequently selected treatment options for correcting anterior crossbites and esthetic problems in the mixed dentition stage. Although the 2x4 appliance is very effective for minor crowding and arch length issues, patients often complain about soft tissue irritation. There are frequent emergency appointments because wires are displaced. This article shares two clinical tips to address these common problems.
Severe open bite and crowding case treated by a new passive self-ligating lingual bracket with square slots
Takemoto K, Takemoto Y, Takemoto A.
A 19-year-8-month male presented with a Class III/II asymmetric malocclusion complicated by severe crowding, anterior open bite, lingually ectopic eruption of the maxillary lateral incisors, steep mandibular plane, and facial asymmetry. The treatment began by using a trans-palatal arch and a mini-screw to intrude maxillary molars for a counter-clockwise rotation of the mandible. Two upper first premolars and one lower right first premolar were extracted, and the malocclusion was treated with passive self-ligating (PSL) lingual brackets with .018x.018” square slots. After 27 months of treatment, a dramatic improvement in both tooth alignment and occlusal function was achieved. (Int J Orthod Implantol 2016;42:108-119)
Key words: Lingual appliance, passive self-ligating appliance, square slot, severe crowding, open bite, asymmetric Class III malocclusion, miniscrew