牙顶

大径指过外螺纹牙顶或内螺纹牙底的圆柱面直径。

The root of the external thread or the crest of the inner thread .

结果表明，牙顶处金属材料受到丝锥棱齿的压力相对较小，并且金属流向牙顶两侧上方的区域时受到的阻力最小；

Through metallographic analysis of the material , microstructure change and deformation mechanism of crest , flank and root of the thread along the layer depth direction were obtained .

结果结合牙龈环切的正畸治疗后患牙牙槽嵴顶高度增加，产生新附着。

Results Orthodontic treatment with circumferential fibrotomy can make new attachment and increase the height of crest bone .

成人正常（牙合）颏顶位X线头影测量研究

The Study of Adult Normal Occlusion Using Submental-vertical Radiographs

结果：（1）在垂直载荷下，2种附着体基牙在牙槽嵴顶处均有应力集中。

Results : 1.Under vertical load , the most extreme stress values were located at the alveolar ridge crest distal / mesial to the abutment of two type of attachment .