OBJECTIVETo provide objective data for position and orientation of zygomatic-area implant used in zygo-buccal flange osseointegrated implant obturator for patients with large maxillary defect.

METHODSFifty cases of normal unilateral zygomatic body with dentition were measured on three-dimensional spiral CT images. Measurements included the slope angle of zygomatic body on sagittal sectional image, the maximal horizontal distance from the buccal boundary of maxillary alveolar to outboard of maxillary sinus. Furthermore, the configuration of zygomatic body was observed on coronal sectional image.

RESULTSThe average rearward slope angle of zygomatic-body was 80.03 degrees. Forty-eight cases showed straight zygomatic-body configurations and two cases quite curvy. The maximal horizontal distance from the buccal boundary of maxillary alveolar to outboard of maxillary sinus was 6.77 mm.

CONCLUSIONSIn a normal condition, implants can be upright inserted tilting about 10 degrees ahead to utilize much zygomatic bone-volume in high site. In order to improve security and validity of implantation, it is better to take spiral CT examination to evaluate the bone volume and shape of zygomatic body before zygomatic-area implant.