Early healing of implants placed into fresh extraction sockets: an experimental study in the beagle dog. De novo bone formation

OBJECTIVES: Describe the early phases of tissue integration in implants placed into fresh extraction sockets and test whether a new implant surface nano-topography (DCD nano-particles, Nanotite) promotes early osseointegration when compared with minimally rough surface implants (DAE, Osseotite). MATERIAL AND METHODS: Sixteen beagle dogs received 64 test and control implants randomly installed into the distal socket of (3)P(3) and (4)P(4). Histomorphometric analysis of bone to implant contact (BIC) and bone area was performed at 4 h, 1, 2, 4 and 8 weeks. RESULTS: Wound healing initiated with a coagulum that was substituted by a provisional matrix at 1 week. Bone formation started concomitant to a marked bone resorption. At 2 weeks, woven bone formation was evident and gradually remodelled into lamellar bone at 4 and 8 weeks. BIC increased similarly throughout the study in both groups with a tendency to higher percentages for the test devices at 2 and 4 weeks. The influence of the DCD nano-particles was more evident at the fourth premolar site. CONCLUSION: Osseointegration occurred similarly at both implant groups, although the socket dimension appeared to influence bone healing. It is suggested that the enhanced nano-topography has a limited effect in the immediate implant surgical protocol.