5504907 Power management system with adaptive control parameters for portable computer

Abstract

The current “gold standard” in alveolar ridge augmentation is autogenous bone grafting. Autologous cortical onlay grafts provide predictable increases in bone volume when used for alveolar ridge augmentation; however, rigid fixation of the graft to the recipient site is essential. Titanium screws are commonly used to provide rigid fixation for onlay grafting but have potential drawbacks including the need for a second surgery for removal before implant placement and screw fracture during removal. The present study investigated the efficacy of resorbable fixation screws to secure autologous cortical onlay grafts to the maxilla or mandible to augment alveolar bone height and/or width before implant placement.Eleven patients requiring alveolar ridge augmentation were enrolled in this study. All patients received autologous cortical onlay grafts. Patients were randomly assigned to receive grafts fixated with 2.0-mm resorbable (experimental) or 1.5-mm titanium (control) screws. Integration and survivability of the graft was assessed using cone-beam computed tomography. Graft resorption was calculated at 4 to 7 months postoperatively and used as a quantitative outcome measurement. Statistical analysis was performed using NCSS/PASS (Dawson edition; Kaysville, UT) for Windows XP. Data are presented as mean ± standard error of the mean. Intergroup differences were assessed using Student's t test.Nine of the 11 patients initially enrolled completed the study. In these patients, 12 bone grafts were placed, 4 fixated with 2.0-mm resorbable screws and 8 fixated with 1.5-mm titanium screws. Integration and survivability of the grafts was 100% regardless of fixation type. Cone-beam computed tomographic data indicated that all grafts integrated regardless of fixation type. At 5 to 7 months postoperatively, cone-beam computed tomographic analysis indicated there were 28.07 ± 3.15% and 40.03 ± 3.67% bone resorption in grafts fixated with 2.0-mm resorbable and 1.5-mm titanium screws, respectively (P > .05).These data suggest that cortical onlay graft integration and survivability are similar using 2.0-mm resorbable or 1.5-mm titanium screw fixation. Therefore, use of resorbable fixation devices in alveolar ridge augmentation will obviate screw removal, which may result in screw breakage and may be difficult if bony overgrowth occurs. Further studies need to be performed with a larger sample to confirm these data.