Effect of geometric dimensions and material models of the periodontal ligament in orthodontic tooth movement
parinaz shokrani, Ata Hashemi, Mehdi Bostan Shirin, Iman Z. Oskui
Abstract
OBJECTIVES: The aim of the present work was set to explore the role of root diameter, root length, and thickness of periodontal ligament (PDL) and its material properties (linear and non-linear elastic material models) on the stress and strain distribution, tooth displacement and centre of resistance (CR) location. SETTING AND SAMPLE POPULATION: Both the bone and the tooth were considered as rigid bodies, and the PDL was modelled as a paraboloid with different geometric dimensions and material properties. MATERIALS AND METHODS: To achieve this goal, a horizontal force of 1 N was applied in the CR location and the stress and strain distribution and tooth displacement were quantified. Locations of CR were estimated through iterative finite element procedure. RESULTS: It was predicted that the position of CR is in the range of 34%-39% of the root length, slightly higher than one-third of the root length reported in the literature. The geometrical dimensions of the PDL had no significant effect on the position of CR, especially in the non-linear material model of the PDL, while the initial displacement of the tooth was found to be highly dependent on the geometrical and mechanical properties of the PDL. CONCLUSION: The simplified PDL modelling approach with non-linear material behaviour can be suggested for the estimation of initial tooth movement for individual clinical applications without the use of advanced 3D scans.