Flapless early implant placement into the uncalcified provisional matrix—Does it lead to osseointegration of the implant? A preclinical study

Aim: To test whether early implant placement into the extraction socket containing an uncalcified provisional matrix leads to successful osseointegration and stable marginal bone levels. Materials and Methods: In six mongrel dogs, the mandibular molars were extracted. Three weeks later, early implant placement was performed according to three experimental protocols: (i) flapless implant placement with preservation of the provisional matrix; (ii) flap elevation, socket debridement and implant placement; and (iii) flap elevation, socket debridement, implant placement and guided bone regeneration (GBR). One untreated extraction socket served as a control group. Data analyses were based on histologic slides 3 months after implant placement. Results: There were no differences in bone-to-implant contact between the three experimental groups (66.97%, 58.89% and 60.89%, respectively) (inter-group comparison p =.42). Marginal bone levels, first bone-to-implant contact as well as the thickness of the connective tissue did not reveal any significant differences between the groups (p =.85,.60 and.65, respectively). Conclusions: Flapless early implant placement into posterior extraction sockets was as effective as an open flap approach in conjunction with GBR. Mineralization of the socket seems to occur irrespective of the presence of dental implants or biomaterials.