Guided bone regeneration using demineralized laminar bone sheets versus GTAM membranes in the treatment of implant-associated defects - A clinical and histological study

This study was designed to compare the regenerative potential at dehisced i mplant sites of the resorbable demineralized laminar bone sheets and non re sorbable GTAM membranes. Twenty-six standard screw-type fixtures showing bu ccal dehiscences in 7 patients were treated using the GBR principles and re ceived either laminar bone sheets (experimental) or GTAM (control) membrane s. Twelve experimental and 10 control sites were available for evaluation a t second stage surgery carried out 8 months following implant placement. He ight and maximum width of the dehiscence defects were measured at the time of implant insertion and at second-stage procedure. Mean percentage of defe ct fill was 75.17% in the experimental dehiscences versus 86.70% in the con trol defects. A statistically significant difference in the percentage of d efect fill could not be evidenced between the two treatment modalities. Com plete fill was observed in 25% of the experimental versus 70% of the contro l sites. A significant difference was found in the median Density Index wit h the GTAM group showing a consistency similar to bone in a larger number o f sites. Histologically. material with the same staining features of bone w as evidenced inside the GTAM membranes in 3 cases while newly-formed bone w as present in all instances under the control GTAM barriers. In the laminar bane-treated sites, the membrane maintained its integrity in almost all ca ses. Newly formed bone was found underlying the membrane in cases with a De nsity Index of 5 with no evidence of bony tissue adhering to the laminar sh eets.