The effect of hyperbaric oxygen (HBO) on the tissue reaction around hydroxyapatite (HA) implants in irradiated bone of rats was investigated. A single dose of 15 Gy was delivered to the right leg of 20 rats. HA implants were placed in the bilateral tibial proximal metaphysis 3 months after irradiation. HBO was administered to half of the rats before and after 15-Gy irradiation. The healing process was examined histologically and histomorphometrically. The results indicated that HBO slightly improved trabecular bone formation in the irradiated bone, accelerated bone remodeling in the nonirradiated bone, and improved HA-bone contact in both the irradiated and nonirradiated bones.

Animals↗

PubMedDate not supplied

Clinicoanatomic examination of the fibula: anatomic basis for dental implant placement.

The advantages of the free vascularized fibular flap include its ability to be shaped with relative ease and to be grafted at the same time tumors are resected, with consequent reduction in operation time. In addition, few complications occur at donor sites. However, a large, systematic, and detailed investigation of clinicoanatomic problems of the fibula has not been performed. Therefore, in the present study, the fibula was examined morphologically and morphometrically, with special attention to regions important in the placement of dental implants. Eighty fibulae obtained from cadavers of 41 Japanese individuals aged 46 to 92 years (mean, 72.7 years) were fixed with 70% alcohol after infusion of about 6 liters of 10% formalin via the femoral artery. Morphometric examination showed the nutrient foramen was located posteriorly in 85.0% of sections, the maximal width of fibular cross sections was 13.1 mm, and the maximal cortical thickness of fibular cross sections was 4.1 mm.

Aged↗

PubMedDate not supplied

Peri-implant tissue reaction in bone irradiated the fifth day after implantation in rabbits: histologic and histomorphometric measurements.

To evaluate tissue reaction to cobalt 60 irradiation around implant materials used in maxillofacial surgery, 2.0-mm titanium alloy bone screws and 2.0-mm cylindrical solid hydroxyapatite implants were placed in mandibular bone of rabbits and irradiated with a single 15-Gy dose on the fifth postoperative day. Tissue reaction around the implants was examined histologically and histomorphometrically at 7, 14, 28 and 56 days after irradiation. Mature bone was relatively radioresistant, but newly formed bone around both implants was damaged by irradiation in several places. After irradiation, the beginning of bone formation was delayed and the amount of new bone formed was less. Bone-implant contact measured histomorphometrically was less in the irradiated group than in the nonirradiated group. All titanium alloy screws showed bone contact, but two of eight hydroxyapatite implants failed after irradiation, probably the result of loss of primary stability of the cylindrical implants caused by radiation damage to newly formed bone.

Alloys↗