Bone modelling at fresh extraction sockets: immediate implant placement versus spontaneous healing: an experimental study in the beagle dog

Objectives: The purpose of this investigation is to describe histologically the undisturbed healing of fresh extraction sockets when compared to immediate implant placement.Methods: In eight beagle dogs, after extraction of the 3P3 and 4P4, implants were inserted into the distal sockets of the premolars, while the mesial sockets were left to heal spontaneously. Each animal provided four socket sites (control) and four implant sites (test). After 6 weeks, animals were sacrificed and tissue blocks were dissected, prepared for ground sectioning.Results: The relative vertical buccal bone resorption in relation to the lingual bone was similar in both test and control groups. At immediate implant sites, however, the absolute buccal bone loss observed was 2.32 (SD 0.36) mm, what may indicate that while an apical shift of both the buccal and lingual bone crest occurred at the implant sites, this may not happen in naturally healing sockets.Conclusions: The results from this investigation showed that after tooth extraction the buccal socket wall underwent bone resorption at both test and control sites. This resorption appeared to be more pronounced at the implant sites, although the limitations of the histological evaluation method utilized preclude a definite conclusion.