Histological Analysis of an Implant Retrieved from a β-Tricalcium Phosphate Graft after 4 Years: A Case Study

We describe the retrieval of a dental implant device that had been successfully osseointegrated for more than 4 years. After obtaining an informed patient consent, the device was retrieved for retreatment purposes from its position in a β-tricalcium phosphate (β-TCP) grafted sinus floor. The sinus floor augmentation, using β-TCP, had been performed in conjunction with the original implant placement, which in turn enabled the histological evaluation of specific regions of interest that were comprised of either grafted or native bone. Radiographs documented the rehabilitated area before and after grafting. The osteogenic events that occurred during the 4-yr-period depict the interplay of implant, synthetic graft material, and native bone in a dynamic process of osteogenesis, ongoing bone maturation, and remodeling that led to the development of haversian-like bone morphology. Two distinct areas were observed histologically, wherein osteointegration occurred uneventfully in both native bone and areas of grafted bone. Of particular interest was the presence of multiple remodeling sites of lamellar bone that could be seen between the plateaus-healing chambers-in which bone eventually evolved into a haversian cortical-like configuration.