An ex vivo investigation into the effects of chemical solvents on the debond behaviour of ceramic orthodontic brackets.

The problems of ceramic bracket debond have been well documented. A peppermint oil material has been marketed previously as a debonding agent. This study assessed ex vivo the effects of peppermint oil application on the debond behaviour of ceramic brackets compared with ethanol and acetone which are recognized softening agents. Intrigue brackets were bonded to 100 extracted premolar teeth. Groups of 20 bonded teeth were then placed in a test solution, control (distilled water), peppermint oil (5 minutes and 1 hour), acetone (1 hour), and ethanol (1 hour). The teeth were debonded using an Instron. Universal Testing Machine and debond forces recorded. The site of bond failure along with the adhesive remnant index was recorded for each tooth. One hour placement in peppermint oil produced the lowest mean and maximal debond forces (77 and 114 N, respectively). Weibull analysis showed that the probability of failure at 100 N was increased for the 1-hour peppermint group at 88 per cent compared with 52 per cent for the control. Placement in peppermint oil produced the lowest levels of retained resin. There was no evidence of enamel fracture with any of the groups, but bracket fracture remained a problem.