Evaluation of tooth discoloration and bleaching response in the presence of clear aligners and attachments

Abstract

Objective To evaluate the influence of clear aligners with and without attachments on tooth discoloration after exposure to common staining beverages, and to assess the bleaching effect of %6 hydrogen peroxide (HP) agent applied through aligners.

Methods Forty extracted human premolars were allocated into four groups (n = 10): attachments only, no aligners or attachments, aligners with attachments, and aligners only. Specimens mounted on typodont models and fitted with Invisalign aligners. Typodont models were sequentially immersed in artificial saliva, tea, coffee, and red wine for 6 days each, simulating 6 months of consumption. Aligners were replaced every 12 hours, and staining solutions were renewed daily. Color measurements were recorded at baseline and after each experimental stage using standardized digital photography, and color differences were calculated using the CIEDE2000 (ΔE00) formula. Following the staining protocol, bleaching was performed for 6 days using a 6% HP based gel applied through aligners. Statistical analysis was performed using the Kruskal–Wallis H test (P < .05).

Results All groups demonstrated clinically perceptible discoloration after staining. The greatest mean color change was observed in the attachment only group (ΔE00 = 23.30), whereas the lowest discoloration occurred in the aligners only group (ΔE00 = 6.60). Red wine produced the greatest color change among staining agents, while tea and coffee produced comparable staining. Bleaching significantly reduced discoloration in all groups.

Conclusion Commonly consumed staining agents produced clinically perceptible tooth discoloration. Composite attachments increased susceptibility to tooth discoloration, whereas aligners showed a protective effect by limiting color change. Bleaching with 6% HP agent applied through aligners significantly reduced discoloration. Dietary habits and the presence of attachments should be considered when managing esthetic concerns during clear aligner therapy (CAT), and bleaching may be recommended without waiting for attachment removal.