Nickel, chromium and methyl methacrylate monomer release from orthopaedic functional appliances.

AIM: This study was purposed to evaluate release of nickel and chromium ions and methyl methacrylate (MMA) monomers from functional appliances and their possible health effects. MATERIALS AND METHODS: Study design: Twin-block appliances and Bionators were immersed in artificial saliva and kept in a thermal incubator. Control group was established as artificial saliva without appliances. Artificial saliva was analysed after 7 days, 30 days and 90 days. Inductively coupled plasma mass spectrometry and gas chromatography-mass spectrometry was used for detection of nickel and chromium ions and MMA monomers. MTT assays and cytokine array were performed. STATISTICS: One way ANOVA with Tukey test and Dunnett's T3 for post-hoc analysis was used for evaluation of time-dependent changes and independent t-test was used for evaluation of MTT assay results. RESULTS: The results revealed that metal ions and MMA monomers are released from the appliances. Metal ion detection pattern was irregular and could not be analysed. Twin-block group showed significantly larger amount of MMA release. MTT assay revealed statistically significant but minimally reduced cellular activity on Bionator and twin-block groups compared to control groups. Cytokine array showed no or less inflammatory cytokine release on Bionator and twin-block groups. CONCLUSION: MMA monomer release was confirmed but the cytotoxic effect of functional appliance material release is minimal or negligible. General toxicity of the functional appliance from the MMA monomer release is likely to be minimal or negligible.