Universidad de Buenos Aires, Facultad de Odontología, Cátedra de Odontología Restauradora, Buenos Aires, Argentina.
Universidad de Buenos Aires, Facultad de Odontología, Cátedra de Materiales Dentales, Buenos Aires, Argentina.
Acta Odontol Latinoam. 2021 Aug 1;34(2):113-118. doi: 10.54589/aol.34/2/113.
The aim of this study was to analyze the dimensions of the clinical crown of upper central incisors and the prevalence of tooth shapes by two different protocols. Assessment was performed on each of the 111 dental stone type V maxillae models of students of dentistry from Buenos Aires University [93 females and 18 males, mean age 23.70 (± 2.26) years] The mesial and distal-vestibular angles were defined on each right upper incisor, and the following segments were defined: AB (zenith - incisal edge), CD, EF, GH (apical, middle, and incisal thirds - vestibule - mesial and vestibule-distal angles) and their lengths were determined with a precision caliper. Then, the CD/AB, EF/AB and mean CD-EF/AB ratios were calculated. Shapes were assessed by four independent observers, three of whom evaluated digital images of the models, while the fourth had no access to the images, and determined the shapes using an algorithm developed from the dimensions of the studied segments. Rates and confidence intervals were determined, and Fleiss' Kappa was calculated to assess the agreement among the evaluators who worked with the images and among all of them. Average incisor length was 10 mm, and widths at CD and EF were 7.35 mm (0.65) and 8.27 mm (0.58), respectively. Regarding shapes, 51.58% (47.90-55.20) of the incisors were identified as square, 18.02% (14.50-21.90) as ovoid and 30.41% (30.00-30.90) as triangular. Fleiss' Kappa agreement was 0.71 (0.62-0.80). The application of the proposed algorithm provided a considerable level of agreement among the observers. Regarding tooth size, both the average segment length and the proportions were similar to those reported by various authors.
本研究的目的是通过两种不同的方案分析上颌中切牙临床冠的维度和牙形状的分布。对来自布宜诺斯艾利斯大学的 93 名女性和 18 名男性学生的 111 个牙石 V 型上颌模型中的每一个进行评估，年龄为 23.70（±2.26）岁。每个右上切牙定义近中-远中颊侧角，并定义以下段：AB（顶点-切缘）、CD、EF、GH（根尖、中 1/3、切 1/3-龈侧、近中-远中龈侧角），并用精密卡尺测量其长度。然后，计算 CD/AB、EF/AB 和平均 CD-EF/AB 比值。形状由四位独立观察者评估，其中三位观察者评估模型的数字图像，而第四位观察者没有访问图像，并使用从研究段的尺寸开发的算法来确定形状。确定了发生率和置信区间，并计算了 Fleiss Kappa，以评估使用图像的评估者之间以及所有评估者之间的一致性。平均切牙长度为 10mm，CD 和 EF 处的宽度分别为 7.35mm（0.65）和 8.27mm（0.58）。关于形状，51.58%（47.90-55.20）的切牙被确定为方形，18.02%（14.50-21.90）为卵圆形，30.41%（30.00-30.90）为三角形。Fleiss Kappa 一致性为 0.71（0.62-0.80）。所提出的算法的应用为观察者之间提供了相当程度的一致性。关于牙齿大小，平均段长度和比例与不同作者的报告相似。
