Initial stress produced in the periodontal membrane by orthodontic loads in the presence of varying loss of alveolar bone: a three-dimensional finite element analysis

Abstract

The aim of this study was to investigate the stress components (S1 and S3) that appear in the periodontal membrane (PDM), when subjected to transverse and vertical loads equal to 1 N. A further aim was to quantify the alteration in stress that occurs as alveolar bone is reduced in height by 1, 2.5, 5, 6.5, and 8 mm, respectively. Six three-dimensional (3D) finite element models (FEM) of a human maxillary central incisor were designed. The models were of the same configuration except for the alveolar bone height. Special attention was paid to changes of the stress components produced at the cervical, apical, and sub-apical levels. In the absence of alveolar bone loss, a tipping force of 1 N produced stresses, which reached 0.072 N/mm2 at the cervical margin, up to 0.0395 N/mm2 at the apex and up to 0.026 N/mm2 sub-apically. In the presence of 8 mm of alveolar bone loss, the findings were -0.288, 0.472, and 0.722 N/mm2, respectively. Without bone loss, an intruding force of the same magnitude produced stresses of -0.0043, -0.0263, and 0.115 N/mm2, respectively, for the same areas and sampling points. In the presence of 8 mm of alveolar bone loss the findings were -0.019, -0.043, and 0.185 N/mm2 for intrusive movement. The results showed that alveolar bone loss caused increased stress production under the same load compared with healthy bone support (without alveolar bone resorption). Tipping movements resulted in an increased level of stress at the cervical margin of the PDM in all sampling points and at all stages of alveolar bone loss. These increased stress components were found to be at the sub-apical and apical levels for intrusive movement.

A comparative study of forces in labial and lingual orthodontics using finite element method

“…Therefore in this study, we focused on the changes in the PDL and studied the maximum principal stresses in PDL. [1][2][3][4][5][6][7][8][9][10] In this study, a tipping force of 50 g was applied labially on the maxillary central incisor 4 mm from the incisal edge. This force was directed horizontally to the tooth.…”

Rotation axis of the maxillary molar and maximum tooth movement according to force direction

“…At the same time, in order to understand the location of the center of rotation, the relationship between the force application area and the rotation axis of the tooth should be observed, taking into account the shape, length, number and location of the roots, as well as the level of the alveolar bone [17][18] . A two-dimensional mathematical model showed that the most occlusal and apical locations of the CRes correspond to triangular and rectangular root shapes, respectively 19 .…”

Assessment of Displacement Contours during Individual Canine Retraction with the Application of Finite Element Method

“…Finite element technique has established itself in dental field involving simulation of tooth movement and evaluating mechanics in orthodontics. Finite element analysis (FEA) is a numerical analysis which permits the identification of displacement and stresses by entangling discretization (hypothetical subdivision of the structure in study) ofits continuum in a large number of elements [3].…”