Propriedades físicas de fios ortodônticos de aço após utilização clínica

Resumo (EN)

Objective: the objective of this study was to evaluate the elastic modulus (E) and superficial morphologic alterations on scanning electron microscopy (SEM) of stainless steel orthodontic archwires after various clinical exposure periods, correlate the E with salivar pH and clinical exposure period. Material and methods: 0.016” pre-formed stainless steel archqires were used. Three point bending tests were performed after periods of 30, 60, 90 and 120 days, a control group was obtained from archwires without clinical exposure (n=4). The results obtained at the three point bending test were used to calculate de E. Salivar pH was mesured by the time of archwire installation and every 30 days until the archwires were retrieved. SEM images were obtained from anterior archwires portions. Results were analized by Kruskal Wallis, method of Dunn and Spearman correlation (=0,05). Results: median E values were 73.49, 78.42, 79.30, 78.73 and 76.13 GPa for control, 30, 60, 90 and 120 days, respectively. Control group presented higher E than 30, 60 and 90 days groups, and it was similar to 120 days group. All groups with clinical exposure presented similar E values. There were no correlation between mean pH and E or period of clinical expusure and E. SEM images showed impurities deposition and morphological alterations after clinical exposure. Conclusion: it could be concluded that period of clinical exposure of 120 days did not influenced E. The pH and period of clinical exposure are not correlated to E. There are superficial alterations after clinical exposure.