Tooth movement tendency induced by orthodontic delta springs with and without helix: a finite element study
Fábio Rodrigo Mandello Rodrigues1; Paulo César Borges1; Marco Antônio Luersen1; Marcelo do Amaral Ferreira2
1 Universidade Tecnológica Federal do Paraná; 2 Orthodontist
doi:10.20906/CPS/COB-2015-0033
Resumo
The purpose of this research is to analyze the influence of orthodontic delta springs with and without upper helix on the tooth movement. Two different types of delta geometries (with and without helix) are analyzed. The springs are made of TiMo alloy wire with a cross section of 0.016 x 0.022 inches. Numerical simulations are performed by three-dimensional finite element models considering large displacements. Within the linear elastic material range, it was found that delta springs with helix can be activated up to 12.0 mm and springs without helix up to 8.0 mm. For the same activation, forces and reactive moments without helix are larger than those produced by delta springs with helicoid. The tooth movement tendencies observed for both orthodontic springs in the sagittal plane, considering the Mz/Fx ratio and the interbracket distance of 24.0 mm, are: not controlled tipping root, controlled tipping crown, translation and controlled tipping root. Also, considering the My/Fx ratio values found for both springs, there is no tendency of tooth movement in the occlusal plane.
Palavras-chave: Biomechanics; Numerical simulations; Moment/force ratio; Finite element method; Orthodontic delta spring