2017 年 58 巻 1 号 p. 107-112
The jawbone exists in a special mechanical environment where it is subjected to functional pressure including occlusal force. The internal structure and bone strength of the jawbone might change as a result of tooth loss and implant placement. Therefore, the local bone quality must be evaluated to elucidate the load environment applied to peri-implant jawbone. The present study was conducted to clarify the nanostructural anisotropy of peri-implant jawbone of beagles by quantitatively evaluating biological apatite crystallite alignment. A total of 12 beagles were divided into four groups (dentate jawbone, edentulous jawbone 3 months after tooth extraction, edentulous jawbone 3 months after placing superstructure, and edentulous jawbone 12 months after placing superstructure). Each group comprised three samples. The fourth premolar was considered as the region of interest, with five measurement points in cortical bone around the implant. Each site was subjected to microbeam X-ray diffraction analysis to evaluate biological apatite crystallite alignment. The results revealed that biological apatite crystallite alignment had been lost in the samples taken after tooth extraction. Furthermore, in the dentate and post-implantation samples, preferential alignment was seen not only in the buccal alveolar region, but also in the infraorbital canal and nasal cavity floors. The results of this study suggested that changes of load environment resulting from dental implant treatment contribute to the expression of unique structural characteristics in peri-implant jawbone, which might affect regions relatively far from implants.
