Analysis of Pulpal Stress in Varied Orthodontic Tooth Movements at Different Bone Levels: A Finite Element Analysis

Abstract

Aim To analyze the pulpal stress in varied orthodontic tooth movements at ideal force levels and different bone levels, and compare any differences in pulpal stress values between anterior and posterior teeth. Materials and Methods Four Finite Element Method models of incisor and molar teeth were simulated with normal bone height and 50% bone height. Each of these models was loaded with five different types of orthodontic tooth movements—Tipping, Translation, Intrusion, Extrusion, and Rotation. The ideal force levels simulated for each type of tooth movement were: Intrusion-20 g, Extrusion-60 g, Tipping-60 g, Translation-120 g, Rotation-60 g. The pulpal stress was evaluated at three levels—pulp chamber, pulp canal, and below root apex, so that we get three values of pulpal stress for anterior and posterior teeth, for each type of tooth movement and its corresponding force level. Results The results showed that in both incisor and molar models with normal bone height as well as 50% bone height, rotation gave the highest pulpal stress while translation gave the least. In both incisor and molar models with normal bone height as well as 50% bone height, pulpal stress was found out to be highest in the root apex region of the tooth. The stress values for incisor and molar models with 50% bone height were found to be almost double that of the models with normal bone height. The pulpal stress for incisor teeth was found to be greater than the molar teeth for all types of tooth movement. Conclusion The present findings indicate that the stress manifested below the root apex is highest. Rotational movements induce the highest stress and translational forces develop the lowest stress related to the physiologic capillary blood pressure. Furthermore, in situations with reduced periodontium, lower forces are needed to reach the maximum tolerable stress compared with teeth with intact periodontium.