Tooth Displacement, Stress Distribution Patterns and Changes in Centre of Resistance in Temporary Anchorage Devices-Assisted Individual Canine Retraction cases, with and without Micro-Osteoperforation

Background: Micro-osteoperforation (MOP) is a minimally invasive technique that can trigger an inflammatory response in the alveolar bone to accelerate orthodontic tooth movement. The procedure characteristically shortens the total treatment duration by lowering the resistance to tooth movement. Aim: The present study compared individual canine retraction with and without MOP in terms of tooth displacement, stress distribution patterns, position of the centre of resistance (CRes) and amount of canine retraction using the finite element analysis (FEA) model. Materials and Methods: An FEA model of the maxilla was created using Autodesk Inventor and Fusion 360 software programs, while a fixed orthodontic appliance was built with stainless steel metal brackets and molar bands in accordance with the MBT 0.022 -inch slot prescription for the maxillary arch. One side of the maxilla, from the central incisor to the second molar, was taken as the experimental side (with MOP), while the other side acted as the control side (without MOP). Results: An important finding of the present study was the change in the position of CRes of the canine which was significantly higher on the experimental side, with the corresponding tooth displacement in this case along the x-axis near CRes being 1.124 x10-5mm, which was higher than that recorded on the control side wherein MOP procedure was not performed (-10.808 x10-5mm). Conclusion: The study concluded that MOP significantly decreased the overall stresses generated in the periodontal ligament and adjacent alveolar bone. Furthermore, the CRes of the tooth moved to a more favourable position facilitating greater tooth displacement, subsequently, increasing the rate of orthodontic tooth movement. Keywords: Tooth displacement, Stress distribution patterns, Centre of resistance, Temporary anchorage devices, Canine retraction, Micro-osteoperforation