Effects of Light-cured versus No-mix and Self-etch Primer Adhesives on Enamel Discoloration following Orthodontic Bracket Bonding

Introdouction: According to the importance of enamel discoloration and controversy regarding the effect of different orthodontic bonding materials on tooth discoloration, the aim of this study was to determine enamel discoloration following orthodontic brackets using different bonding materials. Materials and methods: This in-vitro study, 30 recently extracted human premolars with intact enamel were selected and randomly divided into three groups after primary color measurement (T0). In group A, the specimens were bonded using light-cured adhesive (Transbond XT); in group B, Transbond plus self-etch primer was used; and in group C, unite bond (no-mix) was used on the buccal surface of the specimens. Lingual surfaces, however, did not receive any treatment and were considered as the control group. The samples were immerged in a solution of tea and coffee. After 1 week, the second color measurement was performed (T1) and color changes &Delta;E between pretreatment and post immergence state was evaluated. The third color measurement (T2) was completed after polishing the surfaces with 24-fluted tungsten carbide polishing burs and rubber cups, and color alterations were evaluated between the base and final state. Results: Statistical analysis revealed that in all groups, the enamel color on buccal surfaces had statistically significant color changes in comparison with palatal surfaces between the three stages of treatment (P < 000.1). In groups B and C, &Delta;E (T0&ndash;T2) was clinically significant (&Delta;E > 3.3), and the specimens in group C had the highest amount of changes in all stages of the treatment. Conclusion:Bracket bonding on enamel surfaces with a number of bonding materials in this study led to detectable enamel discoloration, which was the highest when using no-mix bonding material.