Matos Gabriel Ribeiro de, Neto Ruben Ribeiro, Júnior Almiro José Machado, Junior Rui Barbosa Brito
São Leopoldo Mandic Dental School, Campinas, São Paulo, Brasil.
Mechanical Engineering, EMEC, Jundiaí, Brazil.
Eur J Dent. 2022 Jul;16(3):528-535. doi: 10.1055/s-0041-1735435. Epub 2021 Nov 30.
This study aimed to evaluate the influence of three different inclinations of the incisal edge of Planas direct tracks (PDTs) on the upper deciduous incisors (15, 30, and 45 degrees) through simulations using the finite-elements method.
A three-dimensional virtual model of tooth 51 was elaborated by using the Rhinoceros computer-aided design (CAD) software. A mesh was constructed by using the Patran software, and the evaluations were processed by using the ANSYS 15.0 software. The geometry of the elements used consisted of a triangular-base tetrahedron composed of 2,167,386 elements and 3,012,995 nodal points.
Progressive alterations of proportional intensity and distribution were seen in the areas of tension on the dentoalveolar structures, with increasing inclination of the edge of the PDT. The tractive contact tensions were seen to be concentrated in the vestibular apical thirds and palatine cervical thirds, while the compressive contact tensions were in the palatine apical thirds and vestibular cervical thirds.
It was concluded that a 30-degree inclination for the PDT was most appropriate for the cases of anterior crossbite in the deciduous dentition. Nevertheless, because this was a laboratory evaluation, clinical criteria and complementary examinations for each case need to be taken into consideration in making therapeutic decisions.
本研究旨在通过有限元方法模拟，评估普拉纳斯直接轨道（PDT）切缘的三种不同倾斜度（15度、30度和45度）对上颌乳切牙的影响。
使用犀牛计算机辅助设计（CAD）软件构建51号牙的三维虚拟模型。使用帕特拉软件构建网格，并使用ANSYS 15.0软件进行评估。所使用单元的几何形状为由2,167,386个单元和3,012,995个节点组成的三角形底面四面体。
随着PDT边缘倾斜度增加，牙槽骨结构受拉区域的比例强度和分布出现渐进性改变。牵引接触张力集中在前庭根尖三分之一和腭侧颈三分之一处，而压缩接触张力则集中在腭侧根尖三分之一和前庭颈三分之一处。
得出结论，PDT倾斜30度最适合乳牙列前牙反合病例。然而，由于这是一项实验室评估，在做出治疗决策时，需要考虑每个病例的临床标准和补充检查。
