Evaluation of cellular response to collagen membranes enriched with fibronectin light and transmission electron microscope study.

This study was undertaken to evaluate the biocompatibility, cellular reaction and resorption characteristics of a type I bovine collagen membrane material either enriched with or without fibronectin solution in vivo using light (LM) and transmission electron microscopy (TEM). Experimental osseous dehiscence defects were surgically produced bilaterally on the labial aspect of the mandibular 2nd, 3rd, and 4th premolar teeth in four mongrel dogs. Collagen membranes rehydrated with fibronectin solution (group FM) and membranes rehydrated with saline (group M) were placed over the bony defects. The third premolar teeth on which the flap operation was performed served as control (group C), with no membrane placed. Flaps were positioned slightly coronally and sutured. Gingival tissue samples and block biopsies were obtained from all experimental and control sites for LM and TEM evaluation at 7 days. For each group, morphometric analysis was performed and the numbers of macrophages in the most coronal area of the free gingiva were counted. Postoperative healing was uneventful during the experimental period, and all membranes remained covered. Light microscopic evaluation revealed similar resorption patterns in the most coronal area of the membranes both enriched with and without fibronectin solution within the first 7 days. The mean numbers of macrophages were higher in experimental groups than in the control group. In TEM evaluation, more excessive intracellular macrophage activity was observed in group M than group FM. As a result of these observations it may be concluded that similar resorption characteristics existed in the most coronal area in both experimental groups with LM evaluation, but with TEM it was observed that the membranes enriched with fibronectin solution were resorbed more slowly at the ultrastructural level.