JDO Vol. 49

Non-Extraction Treatment of Facial Asymmetry, Midline Deviation, Missing UR4 and TMD

Drs. Huang YH, Lin JJ, Roberts WE.


Abstract

A 24 year 5 month female presented with chief complaints: facial asymmetry, missing upper right premolar (UR4), crowding, and left TMJ clicking.

Diagnosis:Assessment of the face revealed decreased convexity (8˚), increased lower facial height (57%), steep mandibular plane (FMA 30.5˚), as well as mandibular deviation and an occlusal cant to the right (4˚). An asymmetric Class II malocclusion (1mm left and 3mm right) was associated with a maxillary dental midline 3mm to the right, impinging deepbite (6mm, 70%), deep curve of Spee (3mm), wear facet on the UL3 (bruxism), and crowding in both arches (6mm/10mm). The Discrepancy Index (DI) was 30.

Etiology: Constricted arches reflect inadequate masticatory loading, probably relating to the refined diet of most industrialized countries. Decreased arch length secondary to constricted jaws resulted in severe crowding of both arches. The UR4 was previously extracted to make room for the erupting UR3. The facial asymmetry, occlusal cant to the right, and TMJ clicking are probably related to a habitual sleep posture on the left side of the face.

Treatment Plan: Avoid sleeping in the same habitual position, and refrain from wide opening of the jaws, that exceeds the requirement for normal function. Place a full fixed passive self-ligating (PSL) appliance for nonextraction alignment and leveling. Utilize expansion and bilateral infrazygomatic crest (IZC) bone screw anchorage to relieve crowding and correct asymmetry. Correct posterior crossbites with arch coordination and cross-elastics, as needed. Assess the need for more invasive treatment if the current camouflage approach fails to satisfy the esthetic and functional needs of the patient.

Results:A severe malocclusion (DI 30) was corrected to a CRE score of 24 with 33 months of active treatment. Facial form was maintained, the asymmetry was improved ~3˚, and the maxillary dental midline was corrected. TMD symptoms were reduced by correcting sleep posture and establishing a coincident centric relation to centric occlusion relationship.

Conclusion:Non-extraction camouflage treatment, utilizing a low force PSL appliance for arch expansion, and IZC bone screws for retraction, produced near ideal dental alignment (CRE 24). The facial asymmetry and the cant of the occlusal plane was reduced to an acceptable level (~1˚). The patient was well satisfied with the outcomes of the conservative treatment. (J Digital Orthod 2018;49:4-20)

Key words:Facial asymmetry, midline deviation, deepbite, early loss of a maxillary premolar, canting of the occlusal plane, TMJ clicking, passive self-ligation appliance, IZC bone screws, sleep posture, bruxism
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Mutilated Pseudo-Class III Malocclusion with Anterior Crossbite, Knife-Edge Ridges and Periodontal Compromise: Alignment, Sinus Lift, Bone Graft, and Implant-Supported Crowns

Drs. Huang C, Chang CH, Roberts WE.


Abstract

History: A 25-year-old female presented for an orthodontic evaluation with a chief compliant of anterior crossbite. Medical history was noncontributory, and no records of previous dental treatment were available.

Diagnosis and Etiology:The prognathic facial profile was deviated 7mm to the right, and the occlusal plane was canted ~4º. Maxillary midline was deviated 2mm, and there was a 5mm functional shift to the right on closure. With the mandible in centric relation (CR), the facial profile was acceptable. In centric occlusion (CO), the mutilated molar relationships were asymmetric: Class II right and Class III left. The UR5 was missing, and UL6 was hopeless. Microdontia in the lower arch resulted in 2 and 7mm developmental knife-edge ridges distal to the right and left lower canines, respectively. The discrepancy index (DI) was 45 for this severe, complex malocclusion.

Treatment:Despite the risk factors of knife-edge ridges and compromised periodontium, the patient selected conservative, minimally invasive treatment. The occlusion was disarticulated with bite turbos to correct the crossbite with lower arch space closure and Class III elastics. The UL6 was extracted and space for an implant was opened in the UR5 area. Implants were placed to restore both missing teeth (UR5 and UL6). A sinus lift bone graft was required for the UL6. Preprosthetic alignment was completed in 23 mo, and the implant-supported prostheses (ISP) required an additional 8 mo for an overall treatment time of 31 mo.

Outcomes: Preprosthetic alignment and ISP corrected a severe skeletal malocclusion with a DI 45 to a pleasing facial result. Good dental alignment and esthetics were documented by a Cast-Radiograph Evaluation (CRE) score of 26, and a Pink & White dental esthetic score of 3. Consistent with the risk factors defined before treatment, moderate lateral root resorption was noted on the distal surface of the LL3, and ~1mm of bone loss occurred between the LL3 and LL4. No mobility or excessive pocket depth was noted.

Conclusions: A severe skeletal malocclusion with facial asymmetry, missing teeth and periodontal risk factors was treated to a pleasing camouflage result with minimal surgery. Facial asymmetry was improved without orthognathic surgery, but there was still a slight cant to the occlusal plane. Despite some root resorption, bone loss, and irregular gingival margins in the maxillary buccal segments, the patient was pleased with the result and declined further treatment. She was informed that regular follow-up care was essential to maintain her fragile periodontium. (J Digital Orthod 2018;49:26-49)

Key words:Adult treatment, mutilated malocclusion, interdisciplinary treatment, implant placement, functional shift, facial asymmetry, knife-edge ridge, space closure. Class II/III asymmetric malocclusion, sinus lift
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Impacted Maxillary Canines: Facilitating Eruption or Surgical Uncovering

Drs. Tseng L, Chang CH, Roberts WE.


Abstract

A 11y10m female presented in the late mixed dentition stage, as the premolars were beginning to erupt. There was severe anterior crowding in both arches, and the maxillary canines were impacted. One year later the right maxillary canine erupted in a high, blocked out position. After extracting the deciduous canines and opening space as needed, the right canine spontaneously erupted into an acceptable alignment, but the left canine remained impacted. Cone-beam computed tomography (CBCT) accurately displayed the position of the impaction, and the overlying tissue was surgically removed to allow the upper left canine to erupt. The Discrepancy Index (DI) for this complex malocclusion was 15, and the Impaction Specific Assessment System (iSAS) score was an additional 15 points, for a total DI of 30. A passive self-ligating appliance, supplemented with bite turbos on the lower first molars, was used to alleviate the cross-bite of both upper lateral incisors. After 40 months of active treatment, the cast-radiograph evaluation (CRE) score was a marginal 31 points, primarily due to buccolingual inclinations and lack of intermaxillary occlusal contacts. Superimposition of cephalometric tracings showed that the ANB was reduced 1° but the mandibular plane angle increased ~1.5°. The latter resulted in a more feminine facial pattern. Follow-up photographs 1 year and 10 months after treatment revealed that both facial esthetics and occlusion were stable. (J Digital Orthod 2018;49:52-71)

Key words:Impacted upper canine, open window surgery, impaction’s Specific Assessment System (iSAS) , iDI, iCRE
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Insignia® System and IZC Bone Screws for Asymmetric Class II Malocclusion with Root Transposition of Maxillary Canine and Premolar

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


Abstract

An 18-year-old female sought consultation with a chief complaint: poor maxillary anterior esthetics.

Diagnosis & Etiology : Clinical examination revealed facial asymmetry: 1. nasal deviation to the right, 2. occlusal plane canted up on the left side, 3. maxillary midline 1mm left, and 4. mandibular midline 3mm left. Complex malocclusion had: 1. unilateral Class II malocclusion (subdivision left), 2. severe upper arch crowding, 3. blocked-out upper right canine (UR3), 4. mesial root transposition of the upper right first premolar (UR4), 5. lingual crossbite of the upper left lateral incisor (UL2), 6. buccal crossbite of the upper right 2nd molar (UR7), 7. retained upper right deciduous canine and 2nd molar, and 8. an impacted 2nd bicuspid (UR5). The etiology was deemed deviated path(s) of eruption, and habitual sleep posture on the right side of the face. The Discrepancy Index (DI) was 25.

Treatment Plan: 1. extract the retired deciduous teeth and instruct the patient to vary nocturnal sleep positions, 2. use the Insignia® system to produce a digital set-up of the final occlusion and reverse engineer a full fixed passive self-ligating (PSL) appliance to conform to the finishing archwires, 3. place posterior bite turbos on L6s to open the occlusion for correction the UL2 and UL7 crossbites, 4. use bilateral infrazygomatic crest (IZC) bone screws to differentially retract both arches to correct the unilateral Class II malocclusion with midline deviations, 5. move the UR3 mesially with a coil spring, 6. retract the UR4 with an elastomeric chain, and 7. finish with intermaxillary elastics.

Outcomes:This challenging malocclusion (DI 25) was treated in 20 months to a board quality result, as documented with a Cast-Radiograph Evaluation (CRE) of 24 and a Pink & White Esthetic Score of 2. The only significant deficiency was Class II buccal interdigitation on the right side. The patient was very satisfied with the outcome and was pleased with her “charming smile.”

Conclusion: The Insignia® system is very precise and eliminates bracket positioning errors, so few detailing adjustments are required for alignment and finishing. This approach minimizes the repetitive PDL necrosis due to large number of active archwire segments, thereby resulting in a shorter treatment time. However, enamel stripping of the lower incisors and/or increased torque on the maxillary incisors was needed to completely correct the Class II buccal segment on the right side. (J Digital Orthod 2018;49:76-95)

Key words:Insignia® system, passive self-ligating bracket, archwire sequence, custom bracket, canted occlusal plane, root transposition, IZC bone screws, miniscrew, Class II malocclusion, tooth size discrepancy, digital set-up.
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Efficient Bonding Protocol for the Insignia® Custom Bracket System

Drs. Lee A, Chang CH, Roberts WE.


Abstract

The Insignia® appliance is reverse-engineered from a digital set-up of the prescribed dental alignment. Each bracket configuration, and position on the tooth, is specified by the ideal alignment of each tooth engaged on the full-size finishing archwire. Precise bonding of a custom bracket in its designated position is vital for achieving the prescribed intermaxillary alignment without the necessity for detailing adjustments. The recommended bonding procedure for Insignia® is: 1. dry fit jig groups to the appropriate teeth on casts, 2. acid etch, rinse and seal enamel surfaces with primer, 3. coat bracket pads with a thin layer of adhesive, 4. position jigs on the lingual cusp or incisal edge of the tooth, and then roll the coated pad into the proper position on the facial surface, 5. maintain finger pressure on the jigs at about a 45-degree angle to the enamel surface(s), 6. light-cure the resin for half of the recommended time, 7. release the finger pressure and apply the last half of the light cure passively, 8. gently spray the bracket and jig assembly with water to dissolve the soluble glue connecting them, and 9. remove the jig from each bracket, by loosening it with a Weingart utility plier in a mesiodistal direction, and then rotating it to the lingual. Repeat this procedure until all brackets are bonded in the ideal position. (J Digital Orthod 2018;49:100-106)

Key words:Insignia® system, passive self-ligating bracket, bonding procedure, custom bracket, digital set-up
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