A comparative, randomized, prospective, clinical study to evaluate the facial bone and esthetic outcome of buccal augmentation bone grafting techniques in early (type 2) implant placement

The objectives of this study were 2-fold: 1) To determine the clinical reproducibility of the early implant placement and simultaneous guided bone regeneration, as outlined by Buser in 2008; 2) To compare the clinical and radiographic outcomes of this guided bone regeneration technique using either freeze-dried bone allograft or the combination of autogenous bone plus deproteinized bovine bone mineral.;Forty-eight human subjects in two clinical centers will be evaluated. For this thesis, data will be presented for 31 of those subjects. All subjects required extraction of a single maxillary incisor, canine, or premolar that was appropriate for type 2, early dental implant placement. Flapless extraction was completed and the sites were allowed to heal for 4 to 8 weeks. Following soft tissue healing, StraumannRTM SLActive bone level dental implants of varying length and diameter were placed in conjunction with guided bone regeneration. All implants were placed in a standardized position of 2 millimeters palatal to the facial aspect of the adjacent teeth, 3-4 millimeters apical to the final desired free gingival margin, and at least 1.5 millimeters from the adjacent teeth. Subjects were randomly selected to receive either freeze-dried bone allograft or a combination of autogenous bone chips plus deproteinized bovine bone mineral for guided bone regeneration. All bone grafts were covered with a double layer of collagen membrane prior to tension free primary closure. The implants were uncovered after 3 months and a screw-retained provisional was inserted 2 weeks after this appointment. After 6 weeks of tissue shaping, the patients returned to their restorative dentist for fabrication of the definitive restoration. Clinical parameters were evaluated at 6 and 12 months post loading, and cone beam computed tomography evaluation was completed at implant placement and 12 months post loading. Facial bone thickness measurements were completed at 1mm, 3mm, and 5mm from the implant platform.;Discussion: Overall, few documented guided bone regeneration techniques show long-term data and reproducibility. The preservation of grafted and native bone around implants is critical for maintenance of health, function, and esthetic success. Buser described the biologic rationale and treatment sequence for early implant placement in 2008 and states that "the main objective of the concept of early implant placement...is successful contour augmentation of the facial aspect of the implant." He describes how this concept, along with restoratively driven implant placement, will allow for the reestablishment of the desired soft tissue esthetic characteristics seen in natural teeth. While the technique has proven effective in his hands, few have documented its reproducibility. Furthermore, the technique has not been documented using materials other than those outlined by Buser. Freeze-dried bone allograft, if equally successful, is a more cost-effective bone alternative that would eliminate the need to harvest autogenous bone.;Conclusions: Preliminary results from this study suggest that both techniques are effective in augmenting buccal bone with no significant difference in facial bone thickness at one year post-loading. (Abstract shortened by ProQuest.).