Histologic and Histomorphometric Analysis of an Immediately Loaded Implant Retrieved from Man after 14 Months of Loading

Objective: The aim of this study was a histologic and histomorphometric analysis of the peri-implant tissue reactions and the bone/titanium interface in an immediately loaded titanium implant inserted in a soft bone site and retrieved, in man, after a 14-month loading period. Methods. A 65-year-old patient presented with a partial edentulism in the left posterior mandible. The patient was rehabilitated with three dental implants inserted in the left first, second, and third molar sites. All these implants were immediately put into a nonfunctional loading mode and joined with the other implants that supported the temporary restorations. After 14 months, the most distal implant and surrounding tissues were retrieved because of psychological problems of the patient. Results: Newly formed, strongly stained, compact, mature cortical bone with few marrow spaces was observed around the implant, especially in the coronal portion. No inflammatory infiltrate was present around the implant. No gaps or dense fibrous connective tissue were found at the bone/metal interface. No apical epithelial migration was found. In the cortical portion, bone remodeling areas were present with many newly formed Haversian canals. Only in a few areas of the interface was it possible to observe an osteoblast rim. In the apical portion, newly formed bone trabeculae were present; these were composed mostly by woven bone, and only a small quantity of preexisting lamellar bone was present. Histomorphometric evaluation showed that the bone/implant contact percentage was 72.6% (±2.7%). Conclusions: We found that, in immediately loaded implants inserted in soft tissue sites, it was possible to find a high percentage of bone-to-implant contact and that osseointegration was maintained for more than 1 year. This fact could be partly explained with the use of an implant with a rough surface.