用三种测度对楔状缺损形成因素的研究

Studies on the causative factors of cervical wedge shaped defect of human teeth from three dimensions

目的探讨楔状缺损几种致病因素的作用和研究楔状缺损时所用测度的意义。方法设计了缺损侧影深度、面积和缺损体积３种测度，对横刷牙、酸蚀、力疲劳在９对双尖牙实验性楔状缺损形成过程中所起的作用进行了分析。结果证明３种因素单独作用均可致损，但缺损侧影深度间差异无显著性；而３种因素联合致损的速度与缺损程度明显增加（Ｐ＜０．００５），且缺损区牙本质和釉质的硬度显著降低（Ｐ＜０．０５）。以各实验组研究结果计算，一维测度与二维测度之间仅有低度相关，而与三维测度间有中度相关，表明用缺损深度为测度较用其面积更能代表缺损的程度。结论当样本较大且测量条件有限时，研究楔状缺损的问题仍可用一维测度；而当样本量较小，又具备较先进的三维测量设备时，用三维测度可以提高研究结果的敏感度。

Objective To investigate causative factors of cervical wedge shaped defect of human teeth and the significance of methods for measurement of the defect. Methods Experimental cervical defects on 9 pairs of premolars were created by cross brushing, erosion, or fatigue of occlusion force separately or combinedly and measured in depth and area of profile as well as in volume.Results 1.Profile depth of defects caused by three factors separately showed no statistical difference, but the profile depth caused by combining factors was much more than that caused by each individual factor; 2. The hardness of enamel and dentin in defect area was lower than that in normal area of tooth samples; 3. Measurement from one dimension (depth) and two dimension (area) showed only low relation in profile depth, however, measured three dimensionally (volume) there existed moderate relationship. Conclusion For study of cervical defect, the profile depth is feasible provided that is a large sample group and without equipment for volume measuring; if the sample size is limited and there is sophiscated instrument for volume measuring, the 3 dimensional measurement is the most sensitive one.