Recovery of an Inverted Maxillary Central Incisor Impaction with a Dilacerated Root
Drs. Huang YH, Kuo PJ, Lin JJ, Roberts WE.
Introduction: A 19 year- 4 month male presented with a chief complaint (CC) of poor dental and facial esthetics.
Diagnosis: Increased facial convexity (16 ̊) and lower facial height (59%) were associated with a steep mandibular plane (FMA 31 ̊), retrusive maxilla (SNA 80.5 ̊) and mandible (77 ̊), plus an intermaxillary base discrepancy (ANB 3.5 ̊). Moderate anterior crowding was noted in both arches, and molar relationships were Class I. The UR1 was missing, contributing to a 4mm midline deviation and full anterior crossbite. Radiographic images documented complete inversion of the UR1, with a dilacerated root conforming to palatal contour distal to the root of the UR2. The Discrepancy Index (DI) was 28.
Etiology: Severe impaction of the UL1 was apparently due to a deviated path of eruption which may have related to improper development of the tooth, and/or limited space in the arch due to traumatic injury of the primary dentition.
Treatment: Standard torque, passive self-ligating (PSL) brackets were bonded upside down on the upper anterior teeth to prevent labial aring, when the UR1 space was opened. Low torque brackets were bonded upside down on the lower incisors to prevent lingual tipping with Class lll elastics. Two infra-zygomatic (IZC) bone screws were placed buccal to the second molars (IZC 7) to retract the entire maxillary arch. Surgical exposure of the UR1 was performed following 12 months of space opening. A UR1 replica was produced with a 3D printer using the cone-beam computed tomography (CBCT) image. The replica was used clinically to plan the staged path for traction. A slow traction procedure, with regular periodontal maintenance, was performed to avoid a premature perforation of the labial alveolar plate. A rectangular archwire and Warren torquing spring were used to upright the UR1.
Results: Facial esthetics and symmetry were improved, but moderate root resorption was noted for all four maxillary incisors. This challenging malocclusion with an inverted UR1 (DI = 28) was treated in 60 months to an excellent outcome, as evidenced by a Cast- Radiography Evaluation (CRE) score of 17, and Pink & White (P&W) dental esthetic score of 5. The UR1 was recovered and aligned in a satisfactory position, which required only removable retention.
Conclusion: Despite root dilaceration of more than 90 ̊ in the sagittal plane, and a horizontal rotation of the impaction to impinge on the roots of the UR2, the UR1 was recovered and optimally aligned. Complex interdisciplinary care required a long treatment time (60 mo), but resulted in an excellent outcome. CBCT images and 3D printed replicas were valuable for diagnosis and recovery of the complex impaction. (J Digital Orthod 2019;53:4-25)
Key words: Inverted impacted maxillary central incisor, root dilaceration, IZC bone screws, anterior crossbite, CBCT, three dimensional printing, self-ligation appliance, 3D printed replica
Congenital Absence of Maxillary Second Premolars: Orthodontics, Sinus Lift Bone Graft, and Implant-Supported Prosthesis
Drs. Huang A, Lin C, Chang CH, Roberts WE.
History: Congenital absence of maxillary second premolars is a familial trait with a prevalence of about 1.5% worldwide.
Diagnosis & Etiology: A 15-year-11-month old male presented with a chief complaint (CC) of unattractive smile due to irregular teeth and spacing. Both maxillary second premolars were missing. The upper right second deciduous molar was retained, but there was a partially-closed edentulous space on the left side. Clinical examination revealed a bilateral Class I molar relationship, lingually tipped upper and lower incisors (U1-SN 93.5 ̊, L1-MP 85 ̊), upper right canine crossbite, as well as spaces mesial and distal to the lower left canine (LL3). The discrepancy index (DI) was 17.
Treatment: Align the dentition, open space for an implant-supported prosthesis (ISP) to restore the upper left second premolar (UL5). Decrease the width of the upper right primary second premolar to 7mm and retain it for as long as possible. Preprosthetic orthodontics treatment duration was 20 months. Implant placement was delayed for 7 months for completion of adolescent facial growth. The UR5 area implant was placed with a simultaneous sinus elevation graft. After a 5 months healing phase, the implant was uncovered, and soft tissue was formed for 2 months with a healing cap. The abutment was placed and adjusted to achieve 2mm of interocclusal clearance. The final crown was delivered 2 weeks later. Interdisciplinary treatment duration including the growth completion delay was 28 months.
Results:The dentition was aligned and all spaces were closed except for the UL5 edentulous site that was prepared for an ISP. Following completion of the ISP to restore the UL5, the overall treatment was excellent, as evidenced by a Cast Radiograph Evaluation (CRE) score of 17, and dental esthetics pink and white (P&W) score of 3. (J Digital Orthod 2019;53:30-50) and White esthetic score of 4 points. The patient was very pleased with the treatment outcome. (J Digital Orthod 2018;52:24-46)
Key words: Interdisciplinary treatment, adolescent treatment, congenitally missing maxillary second premolar, implant placement, 2B-3D rule, sinus lift, osteotome, bone augmentation
Dento-Facial Asymmetry Treated with the InsigniaTM System and Bone Screw Anchorage
Dds. Chang K, Chang J, Drs. Lee TH, Chang CH, Roberts WE.
History: A 22-year-old female presented with a chief complaint (CC) of anterior crossbite associated with asymmetry of the face and dentition. Her upper left canine (UL3) was extracted at age 12 yr.
Diagnosis: Anterior crossbite with a 3mm anterior functional shift, missing UL3, upper right second premolar (UR5) in buccal crossbite, and 2mm left deviation of the mandible in centric occlusion (Co). The discrepancy index (DI) was 26.
Etiology: Ectopic palatal eruption of the upper left central incisor (UL1) resulted in a functional shift and anterior crossbite.
Treatment:InsigniaTM system appliance with passive self-ligating brackets was constructed for a treatment plan to correct dentofacial asymmetry by extraction of three rst premolars (UR, LR and LL). The UR8 was also extracted, and bone screws were to supplement posterior anchorage. Dentofacial asymmetry was corrected with di erential space closure favoring mesial movement of molars.
Outcome:After 25 months of active treatment, this challenging, asymmetric malocclusion was corrected to a near ideal result with a Cast-Radiograph Evaluation (CRE) of 18, and an excellent dental esthetics (Pink & White) score of 3. (J Digital Orthod 2019;53:56-72)
Key words: InsigniaTM system, passive self-ligating brackets, digital set-up, archwire sequence, dento-facial asymmetry, asymmetrical mechanics, Class II intermaxillary elastics, IZC screw, temporary anchorage devices (TADs)
Improved Archwire Sequence for InsigniaTM
Drs. Yeh HY, Chang CH, Roberts WE.
Archwire sequencing is important for efficient management of malocclusion with a digital appliance. Flexible copper-nickel-titanium (CuNiTi), rigid stainless steel (SS) and adjustable titanium-molybdenum-alloy (TMA) archwires all play a role. There are four phases in Insignia™ progressive archwire therapy: (I) stock light round wires (CuNiTi), (II) rectangular CuNiTi wires, (III) major mechanics with SS, and (IV) finishing with CuNiTi and TMA. This article recommends a revised archwire sequence for InsigniaTM passive self-ligation brackets (SLB) based on clinical experience. (J Digital Orthod 2019;53:76-78)
Key words: InsigniaTM system, passive self-ligating bracket, archwire sequence, custom bracket
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