An basic research on application of dental implants to irradiated bone -effects of HBO-

(1)高压氧对羟基磷灰石种植体周围骨愈合影响的组织形态计量学评价高压氧对受照射大鼠胫骨羟基磷灰石种植体周围组织反应的影响。20只大鼠于15Gy3个月后在胫骨近端干骺端植入羟基磷灰石种植体，一半大鼠在手术前后进行一疗程的高压氧治疗。组织学检查愈合过程。采用组织形态计量学方法对骨髓腔内的骨小梁和HA与骨接触的百分比进行定量。HBO在一定程度上促进了照射骨的骨小梁形成，促进了非照射骨的骨改建，改善了照射骨和未照射骨的HA-骨接触。高压氧对照射后大鼠胫骨中羟基磷灰石(HA)种植体周围组织反应的影响进行了实验研究。照射后3个月，大鼠胫骨植入HA种植体。手术前后对一半的大鼠进行了EBO检查。组织学观察愈合过程。骨小梁体积和HA-骨接触百分率采用组织形态计量学方法进行定量。结果表明，高压氧促进了照射后骨小梁的形成和种植体与骨的接触。然而，即使有高压氧，高剂量照射的骨仍然存在严重的辐射损伤)。

(1) Histomorphometric evaluation of the effect of hyperbaric oxygenation on healing around hydroxylapatite implants in irradiated boneThe effect of hyperbaric oxygen (HBO) on the tissue reaction around hydroxylapatite implants(HA) in the irradiated tibia of rats was investigated. HA implants were installed in the tibial proximal metaphysis of 20 rats 3 months after 15-Gy irradiation.A course of HBO was carried out in half of the rats both before and after surgery. The healing process was examined histologically. Histomorphometric measurements were made to quantify the trabecular bone in the medullary cavity and the percentage of HA-bone contact. HBO improved, to some degree, the trabecular bone formation in the irradiated bone, accelerated the bone remodeling in the nonirradiated bone, and 'improved the HA-bone contact in both irradiated and nonirradiated bones. These results suggested that HBO treatment would be useful for the installation of endosteal implants into irradiated bone.(2) An experimental study on the effects of hyperbaric oxygen with respect to irradiation dosageThe effects of hyperbaric oxygen (HBO) on the tissue reaction around hydroxylapatite (HA) implants in the irradiated tibia of rats with respect to irradiation dosage were evaluated. HA implants were installed in the tibia of rats 3 months after 15- or 25-Gy irradiation. EBO had undergone on half the rats before and after surgery. Healing process was examined histologically. The trabecular bone volume and the percentage of HA-bone contact were quantified histomorphometrically. The results indicated that HBO improved trabecular bone formation and implant-bone contact after irradiations. However, the irradiation damage was still serious in high-dose irradiated bone even with HBO).