Histologic results from a human implant retrieved due to fracture 5 years after insertion in a sinus augmented with anorganic bovine bone.

BACKGROUND: Little is known about the healing pattern and the osseointegration processes at the interface of implants placed into different grafting materials in man. Anorganic bovine bone (ABB) is a xenogenic material with a high biocompatibility and osteoconductivity.

METHODS: A 47-year-old patient underwent a monolateral sinus-augmentation procedure using 100% ABB. Two titanium dental implants were inserted at the same time as the grafting procedure. After 6 months, a fixed prosthetic restoration was placed. After a 5-year loading period, the distal implant fractured, and the implant was removed with a 5-mm trephine bur.

RESULTS: At low magnification, in the peri-implant bone in the grafted area, many particles of ABB were still present. Bone was always interposed between the ABB particles and the metal surface, and in no case were the graft particles in contact with the implant. No acute or chronic inflammatory cell infiltrate or foreign body reactions were present around the particles or at the bone-implant interface. The tissues around the implant were composed of 40% +/- 2.4% bone, 12% +/- 2.9% ABB particles, and 50% +/- 6.2% marrow spaces. The percentage of bone-to-implant contact was 48.6% +/- 3.7%.

CONCLUSIONS: A high percentage (~50%) of direct contact between bone and implant, without the interposition of graft material particles, was present. ABB had enabled implant integration to take place, which had remained stable for 5 years.