中文摘要：

目的基于锥形束CT（CBCT）分析上颌后牙区无牙位点的相关骨解剖特点。方法本项研究共选取了上颌后牙区至少有一个缺牙的100名患者的CBCT图像资料，共217个无牙位点。测量无牙位点的剩余牙槽嵴高度、剩余牙槽嵴宽度和角度A，并分析上颌窦底的形态特点。结果平均剩余牙槽嵴高度为9．53mm，其中小于10mm者占62．67％（136／217）。平均剩余牙槽嵴宽度为9．30mm，大于6mm占91．71％（199／217）。磨牙区剩余牙槽嵴高度小于前磨牙区，剩余牙槽嵴宽度呈相反趋势。上颌窦底形态以倾斜型（64．52％）为主。角度A小于30°、30°-60°和大于60°者分别占10．14％、42．40％和47．47％。结论上颌后牙区缺牙位点进行种植手术前，多数需行上颌窦底提升手术增加骨量，建议根据CBCT检查结果评价上颌窦解剖结构从而制定合理的种植方案。

英文摘要：

Objective This study aimed to analyze the bone anatomy of edentulous sites in the posterior maxillary by cone beam computed tomography （CBCT）. Methods A total of 100 CBCT radiographs from patients with missing maxillary posterior teeth were obtained, resulting in a sample size of 217 edentulous sites. The width and height of edentulous were assessed by three-dimensional reconstruction. In addition, the angle A and morphology of the maxillary sinus walls were evaluated. Results The mean bone height was 9.53 mm, and the percentage of sites than 10 mm was 62.67% （136/217）. The mean bone width was 9.30 ram, and the percentage of sites more than 6 mm was 91.71% （199/217）. The bone height decreased from premolar to molar areas, but the opposite trend was observed in bone width. Regarding the morphology of the sinus floor, 64.52% exhibited an oblique configuration. In angle A, the group of less than 30° was 10.14%, 30°-60°was 42.40%, and greater than 60° was 47.47%. Conclusion A high percentage of edentulous sites in the posterior maxillary requires sinus floor elevation to allow the placement of dental implants. Thus, the use of CBCT scans is recommended to evaluate the anatomical structure of the maxillary sinus for reasonable implant planning.