Evaluation of cytotoxicity of accessories used for traction of impacted teeth

Aim: To test the hypothesis that gold-coated orthodontic accessories used for canine traction are less cytotoxic than those made of stainless steel.
Methods: Six different orthodontic accessories were evaluated, three of them made from stainless steel (1 - bracket, 2 - button, 3 - mesh pad) and three made from a gold-coated alloy (4 - small mesh pad, 5 button, 6 - big mesh pad). Three control groups were also analyzed: Positive control (C+), consisting of Tween 80 cell detergent; Negative control (C-), consisting of PBS; and Cell control (CC), consisting of cells not exposed to any material. Dye-uptake technique, in which neutral red dye is incorporated into viable cells, was used to assess the cytotoxicity of the accessories. Viable cell counting was performed using a spectrophotometer. Data were analyzed statistically by ANOVA and Tukey′s test.
Results: Statistically significant differences (P< 0.05) were found between Groups 1-3 and Groups 4-6. However, no differences were found between Groups 1-3 and Groups C- and CC, and neither between Groups 4-6 and Group C+.
Conclusions: The tested hypothesis was not confirmed since gold-coated orthodontic accessories were found to be more cytotoxic than those made of stainless steel.