Abstract: Objective: To explore the effects of resin adhesive and resin-modified glass ionomer cement on enamel discoloration after orthodontic bracket placement. Methods: 60 freshly extracted premolars were randomly assigned to blank control group, resin adhesive and resin-modified glass ionomer cement group. Measurement of parameters of L*, a* and b* was conducted before bracket placement, after debonding and tea-staining, and △E* was calculated to evaluate color changes. Results: Before and after bracket-bonding, △E* in resin adhesive group (3.18±0.27) and glass ionomer cement group (3.17±0.64) were significantly higher than blank control group (1.89±0.16) (P<0.05); after tea staining, △E* in resin adhesive group (4.25±0.51) and glass ionomer cement group (4.60±0.52) were significantly higher than blank control group (2.43±0.24)(P<0.05) with clinically significant color change in resin adhesive and glass ionomer cement group;no statistical difference was observed in resin adhesive group and glass ionomer cement group. Conclusion: Both resin adhesive and resin-enhanced glass ionomer cement may cause significant enamel discoloration and staining susceptibility, whereas no difference was observed between the two adhesive systems.

Key words: Adhesives, Resin , Glass ionomer cement , Discoloration