Department of Orthodontics, Saint Louis University, St Louis, Mo.
Department of Orthodontics, Saint Louis University, St Louis, Mo.
Am J Orthod Dentofacial Orthop. 2020 Sep;158(3):391-399. doi: 10.1016/j.ajodo.2019.09.013. Epub 2020 Jul 9.
Enameloplasty of maxillary canines is often needed for aesthetic substitution in patients with congenitally missing lateral incisors. The exact enamel thicknesses for the various canine surfaces are unknown because previous studies failed to employ accurate measurement tools to report and compare detailed enamel thicknesses for each surface at various crown heights.
Thirty-two extracted maxillary canines were collected and scanned in a microcomputed tomography scanner. The scans were imported into a custom-written MATLAB software (version 9.2; MathWorks, Natick, Mass) and the enamel thickness on the mesial, distal, labial, fossa, cingulum, and incisal edge of each tooth was computed, obtaining the mean value from slices at 0.1 mm intervals. The overall mean enamel thickness for each surface was also calculated, and these values were compared using paired t tests. Incisal wear stage and incisal enamel thickness that was measured were compared using Spearman rank correlation coefficient.
The mean enamel thickness was significantly thinner at the gingival level when compared with the incisal for all surfaces that were analyzed (1-tailed, P <0.001). The mean enamel coverage at the mesial was significantly thinner than the distal when measured gingival to the widest mesiodistal area. The mean enamel coverage of the cingulum was particularly thin and therefore requires extreme care in reshaping it. Incisal edge enamel thickness was highly negatively correlated with the wear stage of the scoring system that was used (1-tailed, P <0.001).
The enamel coverage of the maxillary canine varies depending on the tooth surface and the incisogingival measurement location.
上颌尖牙的牙釉质成形术常用于替代先天性缺失侧切牙的患者的美学需求。由于之前的研究未能使用准确的测量工具来报告和比较各个表面在不同冠高的详细牙釉质厚度，因此各种犬牙表面的确切牙釉质厚度尚不清楚。
收集 32 颗上颌尖牙并在微计算机断层扫描仪中进行扫描。将扫描结果导入到一个自定义编写的 MATLAB 软件（版本 9.2；MathWorks，马萨诸塞州纳蒂克）中，并计算每个牙齿的近中、远中、唇侧、窝、牙颈和切缘的牙釉质厚度，从间隔 0.1mm 的切片中获得平均值。还计算了每个表面的总平均牙釉质厚度，并使用配对 t 检验进行比较。切缘磨损阶段和测量的切缘牙釉质厚度使用 Spearman 秩相关系数进行比较。
与所有分析的表面的切缘相比，牙龈水平的牙釉质厚度明显更薄（单侧，P<0.001）。当从最宽的近远中区域测量到牙龈时，近中牙釉质覆盖明显比远中薄。牙颈的牙釉质覆盖特别薄，因此在重塑时需要格外小心。切缘牙釉质厚度与所使用评分系统的磨损阶段高度负相关（单侧，P<0.001）。
上颌尖牙的牙釉质覆盖范围取决于牙齿表面和龈牙测量位置。
