Histologic evaluation of a 9-year-old hydroxyapatite-coated cylindric implant placed in conjunction with a subantral...

The histologic examination of dental implants retrieved from humans provides a unique opportunity to evaluate the bone-implant interface. This case report presents a clinical, radiographic, and histologic evaluation of a cylindrical hydroxyapatite- (HA) coated implant retrieved from the posterior maxillary area of a patient after 9 years after placement. The implant had been placed in conjunction with a subantral augmentation procedure with HA as the graft material. Clinical examination revealed an immobile implant with no sign of pathosis. Radiographic examination indicated close proximity of the bone to the implant surface without evidence of radiolucency. Histologically, because of tissue destruction during implant retrieval, only the apical portion of the implant was available for examination under light microscopy, and it appeared to be integrated with the surrounding bone; 45.9% of the surface of the implant had close bone apposition at the interface. There was no evidence of dissolution of the HA coating and the bone appeared to be in immediate contact with the coating. Residual graft particles were present and in close proximity with the implant surface. These observations suggest that the subantral augmentation procedure performed simultaneously with the placement of an HA-coated implant with HA as the graft material apparently resulted in osseointegration between the implant and the surrounding bone. The implant was maintained without complication for 9 years.