Comparison of Friction Force at Contact Surfaces between the Arch Wire and the Slot of Orthodontic Bracket: a Finite Element Method

Orthodontic specialists interest in study of tooth movement mechanic, such as the relationship between applied force and the rate of tooth movement in orthodontic treatment. It is because of the complexity and variety of factors that can affect orthodontic treatment. The friction force at the contact surfaces with an undetermined magnitude, makes the orthodontic treatment unpredictable. In this study, friction coefficient and forces were investigated in new designed bracket that had beveled edge which has been modeled based on standard bracket. Torque, tip and angulations angles of the brackets slot are designed. Arch wires were modeled by two rectangular and circular cross-sections and the effect of geometry on the stress distribution and the friction force was investigated using Finite Element Method (FEM). The results have showed that the stress concentration generated in the bracket which has been the most curvature, decreased compared to the standard bracket at the contact wire and bracket braces. In addition, results have showed that friction in the beveled edge bracket was significantly decline compared to the standard bracket and also are less than the type with minor curvature. Results of investigation of friction between the two types of round and square wire, have revealed that the round wire has lower friction and confirmed previous studies. Finally, due to the reduced friction in the brackets which have been the most curvature, this type of design is appropriate to decrease friction force.