The effect of electric spot-welding on the mechanical properties of different orthodontic wire alloys

• Autor(a) principal: Nascimento,Leonard Euler Andrade Gomes
• Data de Publicação: 2012
• Outros Autores: Santos,Rogério Lacerda dos, Pithon,Matheus Melo, Araújo,Mônica Tirre de Souza, Nojima,Matilde Gonçalves, Nojima,Lincoln Issamu
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Materials research (São Carlos. Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392012000300011
• topic: orthodontic wire; welding; topography; tensile strength

The aim of this study was to test the hypothesis that there is a direct relationship between surface structure and tensile strength of orthodontic alloys submitted to different levels of welding current. Three types of alloys were assessed. One hundred and eight cross-sectional test specimens ("X") were made, 18 for each wire combination, and divided into 6 groups: SS (steel-steel); SN (steel-NiTi); SB (steel-Beta-Ti); NN (NiTi-NiTi); NB (NiTi-Beta-Ti) and BB (Beta-Ti-Beta-Ti), submitted to 6 spot-welding procedures at different levels of current (Super Micro Ponto 3000). Student-Newman-Keuls, Wilcoxon signed-rank, and Kruskal-Wallis tests were used (p < .05). Statistical difference was found between SN group and all the other alloy combinations (p < .05). Initial roughness of alloys ranged from .04 to .55 Ra, with statistical difference between groups (p < .001). The hypothesis was rejected and the tensile strength of Ti-alloys combinations Steel × Beta-Ti was significantly affected by the current level at P50, which changed the properties and structure of the wires.