Abstract
OBJECTIVE: To evaluate the bond efficacy and failure rates of rebonded metallic brackets after enamel reconditioning with chemical 37% phosphoric acid (PA) and natural and synthetic photosensitizers activat-ed by PDT.MATERIALS AND METHODS: A total of 50 non-cavitated, and cautiously extracted human premolars were congregated after sample size calculation. The enamel exterior was etched, washed, dried for adhesive application, and cured. Metallic brackets were then oriented and adapted to enamel surface using composite. Later, brackets were debonded from the surface via a Weingart plier. Enamel was finished for en-suing surface reconditioning. Ultimately, speci-mens were randomly distributed into five groups (n=10). Enamel surface before rebonding was re-conditioned with curcumin photosensitizer (CP), riboflavin photosensitizer (RP), rose bengal pho-tosensitizer (RBP), methylene blue photosensi-tizer (MBP), and 37% PA (control) respectively. After following reconditioning protocol, brack-ets were rebonded to the enamel exterior em-ploying a composite adhesive system. Then, specimens were subjected to the universal test-ing machine for analyzing shear bond strength (SBS), and bond failures were predicted using an ARI index. One-way ANOVA and Tukey mul-tiple comparison tests were used for statistical analysis at a variance value of p < 0.05.RESULTS: Enamel reconditioned with 37% PA demonstrated the highest SBS for bracket rebonding, and the lowest SBS was presented by CP actuated by PDT. Enamel reconditioned with RP and RBP corroborated the analogous SBS outcome to 37% PA. Likewise, enamel sur-face treatment with MBP revealed a statistically significant result to CP for metallic bracket re -bonding. The most prevalent failure scores an-ticipated among groups were 0 and 1 indicating an adhesive failure with the exemption of group 5 (control) that encountered more score 2 cohe-sive failure on debonding metallic brackets from enamel exterior.CONCLUSIONS: Rose bengal and ribofla-vin photosensitizers activated by photodynam-ic therapy with low ARI scores have the poten-tial to be used as viable enamel reconditioning alternatives to 37% phosphoric acid for rebond-ing metallic brackets.