A three-dimensional analysis of enamel thickness and enamel-dentine junction form in permanent human teeth

在本研究中，对318个人恒牙冠进行了微CT扫描，并获得了大腿分辨率体积数据集。数据分析主要集中在167颗未磨损磨牙的近中牙尖切面测量牙釉质厚度。我们得到了以下结果。牙尖尖部和牙合盆的牙釉质厚度与近中牙尖稍有偏差，误差可达0.5~1 mm。我们还发现，侧冠表面的最大径向厚度受截面位置的影响最小，通常误差小于0.1-0.2 mm。中侧牙冠厚度随水平参考面的定义而变化，因此在评估牙釉质分布模式时不如最大侧冠厚度有用。在上颌磨牙和下磨牙的所有位置上，除了尖牙尖和牙尖旁的稀薄牙釉质外，在牙尖尖、牙合盆和侧冠面牙釉质中都可以观察到牙釉质厚度的“功能性”到“非功能性”的侧向梯度。较薄的M1和两个后磨牙之间的厚度在许多但不是所有的厚度测量中都有连续的差异，其模式似乎受到较薄的M1近颊尖牙釉质的影响。最大侧向厚度的个体差异是测量厚度的最小变量，即使控制了序列和颊舌位，也发现个体差异很大。全冠平均釉质厚度与最大侧向厚度之间有很高的相关性，表明最大侧向厚度是预测磨牙牙冠整体釉质厚度的一个有潜力的指标。

In the present study, 318 permanent human tooth crowns were micro-CT scanned and thigh resolution volume data sets obtained. Data analysis focussed primarily on enamel thickness measurements taken in the mesial cusp section of 167 unworn molars. We obtained the following results. Enamel thickness at the cusp tips and occlusal basin in sections slightly offset from the mesial cusp section was found to be inaccurate by up to about 0.5 to 1 mm. We also found that maximum 'radial' thickness of the lateral crown face was least affected by section position, usually with discrepancies of less than about 0.1-0.2 mm. Mid-lateral crown thickness was found to vary by definition of the horizontal reference plane, and thus less useful in evaluating enamel distribution patterns than maximum lateral thickness. In all serial positions in both upper and lower molars, a 'functional' to 'non-functional' side gradient in enamel thickness was observed in cusp tip, occlusal basin, and lateral crown face enamel, with the exception of the characteristically thin enamel at the protoconid and paracone cusp tips. Serial differences in thickness were seen between the thinner M1 and the two posterior molars in many but not all measures of thickness, the pattern of which appears to be influenced by the thin M1 mesiobuccal cusp enamel. Individual variation of maximum lateral thickness, the least variable measure of thickness, was found to be substantial even with serial and buccolingual positions controlled. Correlation between whole crown average enamel thickness and maximum lateral thickness was high, indicating that the latter is a potentially useful predictor of overall enamel thickness of the molar crown.