下颌前磨牙长度、表面积、体积和冠根比值的三维测量研究  

Three dimensional measurements of tooth length,surface area,volume and crown-to-root ratio of mandibular premolars

作　　者：刘琳[1] 李鸿波[1] 赵彤[2] 高羽萱 郭靖[1] 王潇宇[1] 

机构地区：[1]解放军总医院口腔医学中心,硕士生主治医师北京100853 [2]中国科学院大学数学科学学院,副教授北京100190

出　　处：《口腔颌面修复学杂志》2015年第2期72-75,共4页Chinese Journal of Prosthodontics

基　　金：国家自然科学基金(项目编号:3081307);北京市科技计划项目(项目编号:Z141100002114031);北京市科技新星计划(项目编号:2010B078)

摘　　要：目的:探讨根据锥束CT图像三维测量下颌前磨牙长度、表面积、体积和冠根比值的方法。方法:选择离体下颌第一前磨牙16颗、第二前磨牙12颗,采用锥束CT扫描、重建牙齿三维模型,在Geomagic Studio软件中确定各牙齿的长轴、釉牙骨质界,进而测量牙冠、牙根的长度、表面积、体积,每牙测量3次,取平均值。计算各样本的冠根长度比值、冠根表面积比值和冠根体积比值。对下颌第一、第二前磨牙长度、表面积、体积以及三种冠根比值的平均值、标准差、最大值和最小值进行统计,二者间的差异采用t检验。结果:下颌第一、第二前磨牙平均根长分别为14.28、13.24mm,平均冠根长度比值为0.66、0.67;平均牙根表面积222.40、229.96mm^2,平均冠根表面积比值为1.07、0.98;平均牙根体积331.58、354.02mm^3,平均冠根体积比值为0.86、0.77。下颌第一前磨牙与第二前磨牙的牙齿长度、冠长、根长、牙根体积、冠根表面积比值、冠根体积比值之间存在显著性差异。结论:根据锥束CT图像三维测量牙齿长度、表面积、体积的方法可行,为定量、全面评价牙齿的功能提供了新的方法。Objective： To investigate a three dimensional measurement of length, surface area, volume, and crown-to-root ratio of mandibular premolars. Methods： 16 extracted mandibular first premolars and 12 extracted mandibular second pre- molars were scanned by a cone-beam CT and their digital tooth surface images were obtained. After determination of tooth long axis and the cemento-enamel junction, the terminal line between the crown portion and the root portion was determined. The subsequent length, the surface area and the volume of the crown portion and the root portion were measured. Every tooth was measured for three times, and the means were adopted for statistical analysis. The crown-to-root ratio of length, surface area, and volume were calculated for every tooth. The averages, the standard deviations, the extremum values of the indexes were analyzed. The differences between the first and the second premolars were determined using t test. Results： The average root length, root surface area, root volume, crown-to-root ratio in length, area and volume were 14.28mm, 222.40m2, 331.58m3, 0.66, 1.07, and 0.86 respectively for mandibular first premolars, and 13.24mm, 229.96m2, 354.02m3, 0.67, 0.98, 0.77 for mandibular second premolars. There were statistically significant difference in total tooth length, crown length, root length, root volume, crown-to-root ratio in area, and crown-to-root ratio in volume between the two kinds of mandibular premolars. Conclusions： a method of cone beam CT scanning and three dimensional measurement can be used on measurement of length, surface area, volume and the crown-to-root ratio of mandibular premolars can be measured, as well as crown-to-root ratio in length, surface area and volume, suggesting a new way to evaluate prognosis of a tooth that may serve as prosthetic abutment.

关 键 词：下颌前磨牙 牙周膜面积 锥束CT 冠根比 

分 类 号：R783[医药卫生—口腔医学]