Internal structure of zygomatic bone related to zygomatic fixture.

PURPOSE The purposes of this study were to investigate the internal structure of the edentulous zygomatic bone, which provides anchorage for the zygomatic fixture, using micro-computed tomography, and to examine the relation between the internal structure of the edentulous zygomatic bone and the zygomaticus fixture. MATERIALS AND METHODS Twenty-eight zygomatic bones of edentulous maxillae from cadavers were used. The mean age of cadaver specimens was 79.6 years. The specimens were analyzed using micro-computed tomography. RESULTS The internal structure of edentulous maxillae had thicker trabeculae in the region at the tip of the zygomaticus fixture than in other regions. CONCLUSIONS The present findings suggest that the presence of wider and thicker trabeculae at the end of the fixture promotes initial fixation. Also, when the trabeculae are able to support occlusal force after successful osseointegration, this thickening greatly aids the support of the fixture at the tip of the fixture, where stress is thought to be concentrated. In addition, the occlusal force was applied to the entire zygomatic bone. This preliminary study suggests that better understanding of the internal structure of the zygomatic bone will provide further information about the direction of installation of the zygomatic fixture, the ideal position of the zygomatic fixture, and the prognosis of implant therapy.