Stress Distribution and Tooth Displacement Analysis of Maxillary Molar Distalization by Different Designs of Jig in a Finite Element Study.

Abstract

Statement of the problem: Despite the prevalence of CLII malocclusion, still the best mechanotherapy for non-extraction treatment is not verified.

Purpose: The aim of the present study was to evaluate the stress distribution and tooth displacement during maxillary molar distalization with the aid of two different constructions of jigs in three different lever arm heights.

Materials and method: In this finite element study, models were meticulously constructed to represent the maxillary arch teeth (excluding the third molar), periodontal ligament, alveolar bone, maxillary brackets, main archwire, molar bands, jigs, and mini screws. These models were imported into Ansys software for simulation and analysis. Two different jig configurations with three different lever arm height were created. A 150-gram force was applied to simulate tooth movement, facilitate observation, and analyze its effects on oral components.

Results: In various experimental configurations involving tow jigs with differing lever arm heights, the central incisor exhibited displacement characterized by lingual and distal crown tipping, along with evidence of intrusion. Concurrently, the first molar displayed lingual and distal tipping, as well as extrusion, across six distinct modalities.

Conclusion: In the main, posterior teeth showed distal and lingual tipping and extrusion and anterior teeth demonstrated intrusion mesial and lingual tipping in all models. It seems the differences were due to different lever arm heights. Two types of jig had no significant effect on stress distribution and tooth movement.