The Search for the Centre of Resistance of a Tooth Using a Finite Element Model and the Continuum Mechanics

Abstract

In orthodontics, the CR is defined as the ideal point for the positioning of the bracket. This paper presents numerical analyses of a premolar tooth, which aim at searching the centre of resistance (CR) by applying several external torques. We built the geometry of the tooth by making a tomographic renderisation with the software MIMICS. The numerical simulation is performed in the software ANSYS WORKBENCH (ANSYS® Academic Research). The domain of the tooth is discretized using three-dimensional solid elements. The search for the position of CR is made through a heuristic analysis by applying external torques to the model and, afterwards, by seeking the intersection of the neutral planes (where there is no translation). The numerical results showed that the CR is not a point, but rather a region that strongly depends on the relative stiffness between the tooth and the Periodontium (PDL).

The effect of orthodontic extrusion on alveolar bone - a prospective clinical study

“…Vertical movement (VM) of the tooth was presented as the difference between final and initial value (∆CR/SpP or ∆CR/MP). CR was marked as a point on tooth axis in sagittal projection, between coronal and middle third of the root of the tooth, measured from alveolar crest to the apex of the root (Figure 1) [18]. BP/EC and PP/EC presents distance from buccal (BP) or palatal plate tip (PP) to enamel cement junction (EC).…”