Comparative evaluation of different loops for individual canine and en-masse retraction-a finite element method (fem) study

Abstract

The aim and objective was to compare and evaluate the T loop, Mushroom loop and Opus loop for individual canine and en-masse retraction for space closure without preactivation bends using finite element method. The geometric model of maxilla was constructed using CBCT scan. The bracket system simulated was of standard MBT bracket system and arch wire used were 19*25 Stainless Steel and 17*25 TMA for fabrication of loops. There were six different models generated with segmented T loop, Mushroom loop & Opus loop and Continuous T loop, Mushroom loop & Opus loop. The software used for post-processing of the model was ANSYS Hypermesh 2019.0. When retraction forces were given with activation of loops, maximum amount of initial tooth displacement for individual canine retraction was observed for segmented T loop and for en masse retraction it was observed for continuous T loop. Although, there was intrusion of canine for all the three segmented loop, the preferred loop for canine retraction should be segmented T loop and for en masse retraction it should be continuous T loop as it shows least effect of retraction forces on anterior as well as posterior teeth during application of retraction force.