Bone Implant Contact in post-extractive immediately loaded implants.

Objective: the aim of this study was to evaluate histologically and histomorphometrically, the bone-titanium interface (BIC) of post-extractive immediately loaded P.B.R (Primary Bone Reparation) implants. Methods: Previous informed consent 20 patients (both sexes, 42 years mean age, well healthy, no smokers) underwent rehabilitation of the posterior mandible with fixed prostheses, and an additional implant was inserted distally in the mandible. 68 post-extractive immediately loaded P.B.R. implants (TMI®, Pressing Dental, San Marino, Italy) were inserted having minimum implant diameter was 4.2 mm and minimum length was 13 mm. In 10 patients the additional implants were put into nonfunctional immediate loading with a fixed provisional prosthesis on the same day of the implant surgery, whereas in the other 10 patients, the implants were loaded after 75 days. The implant stability quotients at implant insertion were 69 and 66 for the early loaded implants and 68 and 76 for the immediate implants. Before retrieval, the immediate implants were clinically osseointegrated and were not mobile. After 50 and 120 days from surgery the twenty implants (10 immediately loaded and 10 early loaded)) were retrieved with a 5-mm trephine and processed for histological examination. Results: After 50 days, the immediate implants showed a BIC percentage of 69.6%, while the BIC for the early loaded implant was 64.7%. After 120 weeks, the BIC was 85.2% for the IL implant, while for the submerged implant it was 82.3%. Conclusions: Very high BICs were present after 50 and 120 days from surgery around both early and immediately loaded implants. Immediate loading did not impede bone formation in the early healing periods.