Evaluation of Lingual Orthodontic appliances

Due to increasing popularity of lingual orthodontics in recent years, various lingual systems have been developed. In orthodontics Finite Element Method (FEM) has been used to study various types of tooth movement. Although FEM was extensively used for evaluating the biomechanical effects of labial orthodontic forces, research on lingual system is still limited. The purpose of this study is to evaluate the efficacy of two different lingual bracket systems using FEM. FEM of maxilla which included six upper anterior teeth, periodontal ligament has been created. Six upper anterior teeth were digitally arranged in final position using a new computerized method. CAD models of six upper anterior brackets of 7^th generation and Lingual matrix have also been created and attached onto the digital model at appropriate heights. Various orthodontic movements were simulated and force applied distal to the canine bracket. Deformation, stress on teeth, bone and periodontal ligament were studied and compared between the two different lingual systems. Deformation was less with lingual matrix brackets than 7^th generation brackets when subjected to intrusive, retractive and combined forces. More stresses were generated on the teeth, bone and PDL in lingual matrix brackets than 7^th generation brackets when subjected to forces. It was found that tooth movements are more efficient and precise in lingual matrix brackets than prefabricated 7^th generation brackets.