Bio-Oss® Collagen in the buccal gap at immediate implants: a 6-month study in the dog

BACKGROUND: following tooth extraction and immediate implant installation, the edentulous site of the alveolar process undergoes substantial bone modeling and the ridge dimensions are reduced. objective: the objective of the present experiment was to determine whether the process of bone modeling following tooth extraction and immediate implant placement was influenced by the placement of a xenogenic graft in the void that occurred between the implant and the walls of the fresh extraction socket. MATERIAL AND METHODS: five beagle dogs about 1 year old were used. The 4th premolar in both quadrants of the mandible ((4) P(4) ) were selected and used as experimental sites. The premolars were hemi-sected and the distal roots removed and, subsequently, implants were inserted in the distal sockets. In one side of the jaw, the marginal buccal-approximal void that consistently occurred between the implant and the socket walls was grafted with Bio-Oss Collagen while no grafting was performed in the contra-lateral sites. After 6 months of healing, biopsies from each experimental site were obtained and prepared for histological analyses. RESULTS: the outline of the marginal hard tissue of the control sites was markedly different from that of the grafted sites. Thus, while the buccal bone crest in the grafted sites was comparatively thick and located at or close to the SLA border, the corresponding crest at the control sites was thinner and located a varying distance below SLA border. CONCLUSIONS: it was demonstrated that the placement of Bio-Oss Collagen in the void between the implant and the buccal-approximal bone walls of fresh extraction sockets modified the process of hard tissue healing, provided additional amounts of hard tissue at the entrance of the previous socket and improved the level of marginal bone-to-implant contact.