Finite Element Analysis of the Stress Distribution of the Periodontal Ligament of the Maxillary Central Incisors after Orthodontic Treatment

  • Zhe Du
Keywords: Maxillary Central Incisor, Labial–Palatal Inclination, Occlusal Obiquity, Mechanical Model


This study aimed to determine the effect of biomechanical distribution by means of occlusal adjustment when the
maxillary incisor labial–palatal inclination changes. A mechanical model of the maxillary central incisors was
established, where the couple distances between the roots buried in the periodontal tissue with different loads were
chosen to show the effects on periodontal tissue under various bite forces, labial–palatal inclinations, and occlusal
obliquities. In addition, a two-dimensional finite element model of the maxillary central incisors was created under
different labial–palatal inclinations and occlusal obliquities, and the equivalent stress of the periodontal ligament was
selected as the analytical index. The mechanical model suggested that: for the perpendicular load, a larger occlusal
obliquity would reduce stress to the periodontal tissue when the labial–palatal inclination was fixed; and for the vertical
load, occlusal obliquity had little effect on stress to the periodontal tissue, while a larger labial–palatal inclination reduced
stress to the periodontal tissue. The results of the finite element analysis also showed that stress increased with a decrease
in occlusal obliquity with the same labial–palatal inclination, and stress increased significantly under loads perpendicular
to the occlusal surface. As for vertical loads, stress decreased with an increase in the labial–palatal inclination, but the
stress was concentrated in the root tip area. The results showed that if the maxillary central incisor requires occlusal
adjustment after orthodontic treatment, the treatment plan with the greater occlusal obliquity should be preferred.