Browsing by Author "Chiu, Grace"

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    Bimaxillary Protrusion with an Atrophic Alveolar Defect: Orthodontics, Autogenous Chin-Block Graft, Soft Tissue Augmentation, and an Implant
    (Elsevier, 2015-01) Chiu, Grace; Chang, Chris; Roberts, W. Eugene; Department of Orthodontics and Oral Facial Genetics
    Bimaxillary protrusion in a 28 yr female was complicated by multiple missing, restoratively compromised or hopeless teeth. The maxillary right central incisor (#8) had a history of avulsion and replantation, that subsequently evolved into generalized external root resorption with Class III mobility and a severe loss of supporting periodontium. This complex malocclusion had a Discrepancy Index (DI) of 21, and 8 additional points were scored for the atrophic dental implant site (#8). The comprehensive treatment plan was extraction of four teeth (# 5, 8, 12 & 30), orthodontic closure of all space except for the future implant site (#8), augmentation of the alveolar defect with a autogenous chin- block graft, enhancement of the gingival biotype with a connective tissue graft, and an implant-supported prosthesis. Orthodontists must understand the limitations of bone grafts. Augmented alveolar defects are slow to completely turn over to living bone, so they are usually good sites for implants, but respond poorly to orthodontic space closure. However, postsurgical orthodontics treatment is often indicated to optimally finish the esthetic zone prior to placing the final prosthesis. The latter was effectively performed for the present patient resulting in a total treatment time of ~36 months for comprehensive, interdisciplinary care. An excellent functional and esthetic result was achieved, as documented by a Cast-Radiograph Evaluation (CRE) score of 21 and a Pink & White dental esthetics score of 2.
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    Interdisciplinary treatment for a compensated Class II partially edentulous malocclusion: Orthodontic creation of a posterior implant site
    (Elsevier, 2018) Chiu, Grace; Chang, Chris; Roberts, W. Eugene; Orthodontics and Oral Facial Genetics, School of Dentistry
    A 36-year-old woman with good periodontal health sought treatment for a compensated Class II partially edentulous malocclusion associated with a steep mandibular plane (SN-MP, 45°), 9 missing teeth, a 3-mm midline discrepancy, and compromised posterior occlusal function. She had multiple carious lesions, a failing fixed prostheses in the mandibular right quadrant replacing the right first molar, and a severely atrophic edentulous ridge in the area around the mandibular left first and second molars. After restoration of the caries, the mandibular left third molar served as anchorage to correct the mandibular arch crowding. The mandibular left second premolar was retracted with a light force of 2 oz (about 28.3 cN) on the buccal and lingual surfaces to create an implant site between the premolars. Modest lateral root resorption was noted on the distal surface of the mandibular left second premolar after about 7 mm of distal translation in 7 months. Six months later, implants were placed in the mandibular left and right quadrants; the spaces were retained with the fixed appliance for 5 months and a removable retainer for 1 month. Poor cooperation resulted in relapse of the mandibular left second premolar back into the implant site, and it was necessary to reopen the space. When the mandibular left fixture was uncovered, a 3-mm deep osseous defect on the distobuccal surface was found; it was an area of relatively immature bundle bone, because the distal aspect of the space was reopened after the relapse. Subsequent bone grafting resulted in good osseous support of the implant-supported prosthesis. The relatively thin band of attached gingiva on the implant at the mandibular right first molar healed with a recessed contour that was susceptible to food impaction. A free gingival graft restored soft tissue form and function. This severe malocclusion with a discrepancy index value of 28 was treated to an excellent outcome in 38 months of interdisciplinary treatment. The Cast-Radiograph Evaluation score was 13. However, the treatment was complicated by routine relapse and implant osseous support problems. Retreatment of space opening and 2 additional surgeries were required to correct an osseous defect and an inadequate soft tissue contour. Orthodontic treatment is a viable option for creating implant sites, but fixed retention is required until the prosthesis is delivered. Bone augmentation is indicated at the time of implant placement to offset expected bone loss. Complex restorative treatment may result in routine complications that are effectively managed with interdisciplinary care.