Resumen
Objective: Premature exposure of membranes used in guided bone regeneration (GBR) results in decreased bone formation. The effect of an expanded polytetrafluoroethylene (e-PTFE) and two collagen membrane on bone healing of buccal dehiscence defects around implants in cases with and without premature membrane exposure was clinically evaluated. Methods: Three groups were established: Group OS (Ossix (TM), n=73 implants, 41 patients), Group BG (Bio-Gide (R), n=53 implants, 28 patients) and Group GT (e-PTFE, Gore-Texs, n=34 implants, 17 patients). Defect height and width were measured at the time of implant placement and at second stage surgery. Surface area was calculated as half ellipses. When several implants were placed simultaneously, a mean of their defect width and height was calculated. Results: Mean percentage reduction of defect area (92.2 + - 13.78 percent Group OS, 94.6 + - 6.69 percent Group BG, and 97.3 + - 4.91 percent Group GT) and height (81.6 + - 23.19 percent, 85.4 + - 12.26 percent, and 93.4 + - 9.39 percent respectively) did not show statistically significant differences between groups. Differences between groups were not statistically significant for all parameters when cases without spontaneous membrane exposure were compared. However, differences were significant when spontaneous membrane exposure occurred. Mean percentage reduction of defect area among cases where membrane exposure occurred was 91.5 + - 10.86 percent Group OS, 71.5 + - 8.61 percent Group BG, and 73.7 + - 13.97 percent Group GT. Mean percentage reduction of defect height among cases with membrane exposure was 76.4 + - 18.28 percent, 53.4 + - 9.86 percent, and 49.4 + - 11.05 percent, respectively. Conclusions: Premature exposure of membranes and subsequent and consequent exposure of implants results in impaired bone healing. Certain barrier membranes, as used in group OS, are apparently capable of supporting gingival healing even when prematurely exposed that could be advantageous in GBR procedures.(AU)
