New attachment and bone formation in periodontal defects following treatment of submerged roots with guided tissue regeneration.

The purpose of the present study was to examine the effect on periodontal regeneration of preventing bacterial contamination of the membrane material following the guided tissue regeneration procedure (GTR). Periodontal dehiscence defects were surgically produced in 2 monkeys. In each monkey, 8 of these defects were submerged after resection of the crowns of the teeth and a teflon (Gore-Tex Periodontal Material) or a polyglactin (Vicryl Mesh) membrane was adjusted to cover the defect and the exposed root surface. 4 defects on non-crown resected teeth were treated with either a teflon or a polyglactin membrane positioned with the coronal border approximately 2 mm below the margin of the covering tissue flap. Following 6 months of healing, the animals were sacrificed. Histological evaluation of the specimens revealed that roots which were kept completely covered during the healing period demonstrated new connective tissue attachment and bone formation corresponding to 67-100% of the length of the initial defect depth, whereas the amount of new connective tissue attachment and bone on non-submerged roots ranged between 30-59% and 11-31%, respectively. It seems reasonable to anticipate that it is bacterial contamination of the membrane material which jeopardizes the formation of new connective tissue attachment but in particular bone formation following the GTR-procedure.