IZC Bone Screw Anchorage for Conservative Treatment of Bimaxillary Crowding in an Asymmetric Class II/I Subdivision 1 Malocclusion
Drs. Chang MJ, Lin JJ, Roberts WE.
Introduction: A 23-year-old male presented for orthodontic consultation to evaluate chief complaints of severe crowding and protrusive lips.
Diagnosis: Clinical and radiographic examination revealed a convex facial profile (G-Sn-Pg’ 19°), protrusive lips, hypermentalis activity, coincident midlines, mandible deviation to the right, asymmetric Class II/I subdivision-right malocclusion, narrow arches, 7-8mm of crowding in each arch, and a relatively high mandibular plane angle (SN-MP 37°). The Discrepancy Index was 20 points.
Treatment: All permanent teeth were erupted except for horizontally impacted lower third molars. Following extraction of all four third molars, a passive xed self-ligating appliance was installed. Infrazygomatic crest (IZC) bone screws were inserted buccal to the upper molars to provide posterior skeletal anchorage to retract both arches. Expansion of the constricted maxillary arch was initiated with light buccal force, that was delivered with a circular-formed 0.016-in copper nickel titanium (CuNiTi) archwire. The bite was opened with an anterior bite turbo, and all four buccal segments were di erentially retracted, to correct intermaxillary crowding and asymmetric Class II interdigitation, with IZC anchorage and Class III elastics. Third order correction and nishing were accomplished with rectangular archwires and a root torquing auxiliary. Active treatment time was 26 months.
Outcomes: Excellent dental and periodontal results were achieved: Cast-Radiograph Evaluation of 21 and a Pink & White Esthetic Score of 5. Lip protrusion and incompetent lips were corrected to the patient’s satisfaction, but there was a 2mm retraction and 2° clockwise rotation of the mandible, that increased both the lower facial height (LFH) and facial convexity (FC).
Conclusions: Retrospective analysis indicated that the mandibular retrusion and clockwise rotation were related to extrusion of the lower molars, and an undiagnosed sagittal slide in occlusion (CR to CO discrepancy), as evidenced by wear facets on the initial casts. (Int J Orthod Implantol 2017;48:4-22)
Key words:Asymmetric Class II/I, Subdivision 1 malocclusion, passive self-ligating appliance, extra-alveolar (E-A) bone screw anchorage, infrazygomatic (IZC) miniscrew anchorage, anterior bite turbo, sagittal slide in occlusion, centric relation and centric occlusion discrepancy, wear facets
Conservative Management of Skeletal Class II Malocclusion with Gummy Smile, Deep Bite, and a Palatally Impacted Maxillary Canine
Ms. Ariel Wong, Drs. Chang CH, Roberts WE.
Introduction: A 21-year-old female presented with chief complaints of crooked teeth, canine impaction, deepbite, and “gummy smile” (excessive maxillary gingival exposure when smiling).
Diagnosis: Increased facial convexity (15.5o), increased lower facial height (56%), and incompetent protrusive lips (E-line to UL 2mm, E-line to LL 2mm) were associated with a severe Class II malocclusion (nearly a full cusp bilaterally). There was 7.5mm of overjet, 100% anterior deepbite, and a left posterior buccal crossbite. Cephalometrics revealed a skeletal discrepancy due to a protrusive maxilla and a retrusive mandible (SNA 85o, SNB 78o, ANB 7o). Cone-beam computer tomography (CBCT) imaging revealed a palatally impacted right maxillary canine (UR3) in close proximity to the adjacent lateral incisor (UR2).
Treatment: The retained right primary canine (URc) was extracted. A simpli ed open window technique was utilized to surgically expose its impacted successor. A maxillary anterior miniscrew provided anchorage to align the UR3 in its correct anatomical position. Non-extraction treatment with a passive self-ligating fixed appliance was indicated to align and level both arches. Anchorage provided by infrazygomatic crest (IZC) bone screws and maxillary anterior miniscrews was used for correction of Class II malocclusion and gummy smile. To achieve more esthetic crown lengths in the maxillary anterior segment, gingivectomy was performed with a diode laser 2 months after xed appliances were removed.
Outcomes: This challenging skeletal Class II malocclusion with a Discrepancy Index (DI) of 38, was treated in 32 months to excellent outcomes: Cast-Radiograph Evaluation (CRE) score of 25, and an Pink & White dental esthetic score of 2. All facial and dental corrections were stable at the six month follow-up evaluation. (Int J Orthod Implantol 2017;48:24-46)
Key words: Gummy smile, deepbite, Class II malocclusion, palatal canine impaction, self-ligating brackets, bite-turbos, temporary anchorage devices, arch retraction, laser gingivectomy, infrazygomatic crest, extra-alveolar, bone screws
Bimaxillary Protrusion Treated with Insignia® System Customized Brackets and Archwires
Drs. Chang C, Lee A, Chang CH, Roberts WE.
Introduction: Correction of bimaxillary protrusion is challenging, particularly without orthognathic surgery and/or temporary anchorage devices. A viable option is bimaxillary space closure following extraction of premolars in all four quadrants. This time consuming and technically challenging approach is facilitated with a digital custom appliance.
Diagnosis: A 12yr 6mo old boy presented with a chief complaint of lip protrusion. The diagnostic evaluation revealed a convex pro le (15°), slight skeletal protrusion (ANB 83o, SNB 80o, ANB 3o), steep mandibular plane angle (FMA 33°), bimaxillary lip protrusion (3mm/5mm to the E-Line), ared incisors (18°/92°), excessive overbite (5mm), deep curve of Spee (4mm), and a Discrepancy Index (DI) of 20.
Treatment: All four rst premolars were extracted and a customized appliance (Insignia® system), with self-ligating brackets and progressive archwires, was constructed by reverse engineering from a digital set-up. Extraction spaces were successfully closed in all four quadrants. There were two minor molar alignment problems and inadequate lingual torque expression on the UL1. All of these discrepancies were attributed to undetected errors in the digital set-up. Active orthodontic treatment was accomplished in 13 appointments over 19 months.
Outcomes:Excellent dental alignment and esthetics were documented with a Cast-Radiograph Evaluation (CRE) of 21, and a Pink & White Esthetic Score of 5. Compared to about 36 months for conventional extraction treatment of bimaxillary protrusion, the Insignia® appliance provided an almost 50% decrease in treatment time (19 months). The patient and his parents were pleased with the dental alignment, facial esthetics and relatively short treatment time.
Conclusion: The Insignia® digital appliance is very accurate, and precisely aligns the dentition according to the digital set-up, but torque compensations are required for mechanics that signi cantly move the roots of teeth. With correct treatment planning, the outcomes are enhanced by minimal treatment adjustments, thereby producing fewer therapeutic lag phases due to PDL necrosis. Thus decreased treatment time is due to continuous low force mechanics with few adjustments. (Int J Orthod Implantol 2017;48:50- 70)
Key words: Insignia® system, customized passive self-ligating bracket, digital set-up, bimaxillary protrusion, extraction of premolars, incisor retraction, bite turbos, early light short elastics, decreased treatment time, lag phase due to PDL necrosis
Severe Malocclusion with Openbite, Incompetent Lips and Gummy Smile (DI 29) Treated in 16 Months with Clear Aligners to a Board Quality Result (CRE 18)
Drs. Peydro Herrero D, Chang CH, Roberts WE.
History: A 30-year-old male presented with chief complaint (CC) of openbite, occasional TMJ pain, a shift when biting, and “gummy smile” (excessive gingival exposure). Modi ed Palmer nomenclature for this report is upper (U), lower (L), right (R), left (L), and teeth are 1-8 from the midline.
Diagnosis: Facial analysis revealed: decreased facial pro le (10.5°), increased lower facial height (LFH)(58.9%), bimaxillary protrusion tendency (SNA 83°, SNB 82.5°), lip incompetence, excessive upper lip elevation when smiling, mandibular deviation to the right, occlusal plane canted up 4° on the right, slightly protrusive mandible, incompetent lips, gummy smile, and dark buccal corridors. Compared to the facial midline, the upper midline was 2mm right, and the lower midline was 4mm right.
Dental evaluation showed: Class I occlusion except for a 2-3mm Class II UR3, ~3mm of crowding was noted in each arch, upper incisors tipped lingually (SN 100°), lower incisors tipped labially (MP 93.5°), 2mm CR→CO shift anterior and to the right due to a crossbite of a LL5, and 1-2mm loss of alveolar bone height between the LR3 and LR4.
Etiology:Probable etiology, for this acquired asymmetric malocclusion with increased LFH, was deemed a juvenile airway obstruction that resulted in a low tongue posture, interincisal tongue position, and posterior rotation of the mandible. Facial deviation to the right re ects a habitual sleeping pattern on the left side.
Treatment: An iTero Element® intraoral scanner and ClinCheck® treatment planning system were used to specify 31 Invisalign® aligners (Align Technology, Inc, San Jose, CA, USA) to: 1. expand, align and level both arches, 2. resolve the right canine Class II relationship, 3. correct incisor axial inclinations, 4. close the openbite by extruding lateral incisors, and 5. reduce the gummy smile by retracting incisors to correct incompetent lips. Phase 1 was 19 aligners for initial alignment and Phase 2 was 12 aligners to detail and nish. This complex malocclusion was treated in 16 months, and the patient was trained in lip seal exercises, natural lip elevation, and varied sleep positions.
Outcomes: A severe complex malocclusion with an American Board of Orthodontics (ABO) Discrepancy Index (DI) of 29 was treated to an excellent result, as documented by an ABO Cast-Radiograph Evaluation (CRE) score of 18, and a Pink and White (P&W) dental esthetic score of 1. Comprehensive analysis revealed an improved facial pro le, competent lips, and more natural smile line, but there was no change in facial deviation and cant of the occlusal plane. The patient’s CC (TMJ pain, bite shift and gummy smile) was resolved to his satisfaction.
Conclusions: This is the rst comprehensive case report of a severe, complex malocclusion (DI 29) treated with clear aligners to a board quality result (CRE 18, P&W 1). (Int J Orthod Implantol 2017;48:74-94)
Key words: Invisalign, aligner treatment, anterior openbite, gummy smile, intermittent TMJ pain, incisor retraction, competent lips, lower face deviation, function shift
TruRoot®: Increasing simulation accuracy of Insignia® by CBCT
Drs. Lee A, Chang CH, Roberts WE.
CBCT-generated TruRoot® data is integrated in the Insignia® system for precise root positions and low dose radiation exposure, which provides more reliable Insignia-simulated treatment results. Furthermore, clinicians using the Insignia Approver® software, no longer have to guesstimate root problem while ne-tuning the nal occlusion. In addition, any signs of root resorption can be more easily identi ed by CBCT and checked in the Approver®. (Int J Orthod Implantol 2017;48:98-99)
Key words:Insignia system, passive self-ligating bracket, custom bracket, CBCT
Refinement of Gingival Margins: Biological Depth vs. Zone, and a Diode Laser
Dds. Chang J, Shern L, Chang K, Dr. Roberts WE.
Gingivectomy re nes dental esthetics by correcting gingival margins and improving dental crown forms to enhance outcomes for orthodontic and interdisciplinary treatment. The predictability of a gingival revision depends on preoperative planning, which is based on a thorough understanding of the form and function of a healthy periodontium. The epithelial attachment (EA) is composed of three periodontal tissues: sulcus depth (SD) of marginal gingiva, connective tissue attachment (CTA), and junctional epithelium (JE). The combination of two anatomical tissues (CTA and JE) is de ned as the biologic or biological width. It is the physical barrier that protects sterile internal tissues from the microbes of the oral cavity. The tissues of the biological width are bordered and protected by an immunologic buffer zone (SD). In effect, all three tissues (SD, CTA, JE) function together as a biological zone, which is an essential physiologic barrier between the oral cavity and alveolar bone. The biological zone must be preserved during a gingivectomy procedure, to avoid the longterm chronic inflammation due to a biological width violation. The traditional method for removing excessive gingival tissue is excision with a scalpel, which has the disadvantages of a long and relatively complex operation, followed by an extended healing interval. Oblation of excessive gingival tissue with a diode laser reduces the duration and complexity of the surgical procedure, plus it shortens the recuperative (healing) period. Additional advantages of laser surgery are minimal probability of infection, and little or no pain. Diode lasers are a superior gingivectomy option for both patients and clinicians, but the biological zone must be respected. (Int J Orthod Implantol 2017;48:104-108)
Key words: Gingivectomy, biologic or biological width, connective tissue attachment, junctional epithelium, sulcus depth, biologic or biological zone, diode laser.