Biocompatibility of self-etching primer in orthodontics: an in vitro study.

OBJECTIVES

Self-etching primers have simplified the process of direct bonding of dental resins and orthodontic brackets. The aim of this study was to evaluate the cytotoxic impact of the leached components to L-929 fibroblast cultures.

METHODS

Transbond™ Plus self-etching primer (3M Unitek, 2724 South Peck Road, Monrovin CA 91016 USA) was applied to enamel pieces in three different conditions and the specimens were added to L-929 fibroblast cultures. The incubation time was 72 h and the cells were counted by flow cytometry. Statistics was carried out using descriptive and explorative data analyses.

RESULTS

In direct contact assays, the self-etching primer without bracket exhibited mild to moderate cytotoxicity. The application of primer, composite and bracket showed no relevant decrease of cell viability. After seven days, the cytotoxic effects had largely disappeared. Overall, the combination of self-etching primer, composite, bracket exhibits no significant cytotoxicity during the observation period.

CONCLUSIONS

When self-etching primers are used according to the recommended clinical protocols in orthodontics, the method is regarded as safe and the release of leachables seems to have no adverse clinical effect.