【摘要】 通过比较１７例无牙颌患者５年前后的头侧位Ｘ线片，发现下颌角点、髁状突顶点、喙突顶点构成的三角形面积Ｓ_１５年前后变化无显著性差异，提示　的值比Ｓ_２更准确地反映牙槽骨的吸收程度。更多还原

【Abstract】 Abstract The purpose of this article is to demonstrate the basis by means of determining the degree of the residual ridge resorption of alveolar bone.The cephalographs of 17 edentulous patients(8 women and 9 men)were studied.Tracing made from the cephalometric films taken at the start of the study and after 5 years were measured in square millimeters with the special plamimeter.There was no significant difference between the two time in the area(S1)that followed the mandibular angle to the apex of the condyle to the apex of the coronoid process,while the area(S2) that followed the uppermost contour of the inferior border of the mandible from gnathion to Id-40,perpendicular to the crest,then forward to the symphsis and return to gnathion,was significantly smaller in the second time than the first time.To indicate the degree of the residual ridge resorption,the area of was more precise that that of S2.更多还原