Evaluation of the effects of different fixed functional appliances used in mandibular advancement on dentoalveolar structures using finite element analysis method

Introduction and Aim: The aim of this study is to evaluate the effects of the PowerScopeR2 (2014 American Orthodontics Corporation, Sheboygan, Wisconsin) appliance, which is newly produced and of which clinical application is easier than many other fixed functional apparatus, on the structures of mandible, maxilla and dentoalveolar using finite analysis method in vitro and to study and compare the differences of its effects from ForsusTM Fatigue Resistant Device EZ2 appliance (FRD; 3M Unitek, Monrovia, California ) and Herbst (Dentaurum Inc., Newtown) appliance which are widely used in routine clinic practices. Material and methods: The three-dimensional finite element model of the jaw bones was obtained via cone beam tomography of an individual whose growth development was completed and it was provided by the firm where the study was conducted (Ay Tasarım, Ankara). Forsus, PowerScope2 and Herbst appliances were used in three separate finite element models and the values of von Mises stress, minimum-maximum principal stress and displacement on teeth, dentoalveolar structures and jaw bones were evaluated via finite element analysis method. Results: More protrusions were observed in the lower incisors of the model applied with PowerScope2 appliance when compared with the models applied with Forsus and Herbst appliances. Von Mises stress values were observed to be quite high in the models where Herbst appliances were applied when compared to the other two appliances. The amount of distalization in the upper jaw molar teeth caused by fixed functional appliances was observed to be the highest in the model where the Herbst apparatus was applied. Conclusion: In our study, it is observed that the high von Mises stresses were seen in the teeth where the force was transmitted in all simulations. It has been found out that PowerScope2 appliance, which is newly produced and can be applied easier when compared with the other two appliances, creates similar effects as the other two and that additional precautions should be taken to prevent undesirable buccal tiping effects in upper jaw and unwanted maxillary molar distalization in retrognatic patients. Keywords : Forsus, PowerScope, Herbst, Finite element analysis, Functional therapy