The effect of non-resorbable membrane on buccal bone healing at an immediate implant site: An experimental study in dogs

Objective: For successful implant treatment in the esthetic area, stable hard tissue and soft tissue are very important. At the buccal side without buccal bone defects, prophylactic guided bone regeneration (GBR) with bone substitute was frequently used for achieving thick buccal bone. The aim of this study was to evaluate the effect of GBR using a non-resorbable membrane in an immediate implant site without bone defects. Material and methods: Immediate implants were placed into the mandibles of four mongrel dogs. In the experimental group (TM group), a non-resorbable membrane was placed and fixed onto the buccal bone plate around the implant. In the control group, the implants were placed without membrane coverage. After 12 weeks, the dogs were sacrificed and histological specimens were prepared. The vertical distances from the smooth-rough surface interface (SRI) to the gingiva, the first-bone contact, and the bone crest were measured on the buccal and lingual sides. The horizontal thicknesses of the gingiva and bone at 0, 1, 2, and 3mm below the SRI were measured. Results: In the TM group, first-bone contact on the buccal side was more coronally positioned approximately 0.8mm than the control group (P=0.041). The buccal bone thickness of the TM group was well preserved and there was no difference between the buccal and lingual sides. Comparing the control group, implants of the TM group had 1mm thicker buccal bone (P=0.0051 at bone 1mm level, P=0.002 at bone 2mm level). In the control group, buccal bone loss was observed and buccal bone was about 1mm thinner than the lingual bone (P<0.05). Conclusions: GBR with a non-resorbable membrane and no bone graft substitute could help to preserve buccal bone thickness on the immediate implant site without defects.