下颌骨各部位曲面体层影像放大率的定量分析

A Study of the Magnification of Mandible Pantomography Image

目的 研究下颌骨各部曲面体层影像的放大率。方法 5 0个下颌骨标本 ,在标志点上嵌入铅粒 ,进行曲面体层投照。测量片上各测量点间的距离 ,进行统计学处理。结果 TROPHYXL 90C机器下颌骨影像平均放大率为 1.2 2 ,横向平均放大率为 1.14,纵向平均放大率为 1.2 9。横向放大率以体部为最大 (1.2 4) ,颏部最小 (1.0 8) ;而纵向放大率各部位较相近 (1.2 8～ 1.30 )。各部位纵向放大率大于其横向放大率。结论 下颌骨各部位影像放大率的确定 。

Objective To study the degree of magnification of mandible pantomography image. Methods The pantomography of 50 mandible specimens marked with lead pellets were taken by TROPHY XL 90C .The distances between each markers on film and in specimen were measured.Results The mean magnification(MM) of mandible pantomography image with TROPHY XL 90C was 1.22. MM of horizontal axle was 1.14. MM of vertical axle was 1.29. MM of horizontal axle was greatest (1.24) in the body of mandible ,and lest (1.08) in genion . MM of vertical axle is similar among each regions. MM of vertical axle was greater than that of horizontal axle in all regions.Conclusion The MM parameters of mandible pantomography image were useful to estimate the size of mandible lesions and provided a basis for dental implant more exactly. [