Influence of smoking on the effectiveness of at-home bleaching with 22% carbamide peroxide: A cohort study

Abstract ObjectivesTo evaluate the effect of smoking on tooth whitening and color change after at-home bleaching.Materials and methodsThis is a cohort study evaluating two groups of participants: NS- non-smokers (n = 24) and S- smokers (n = 16). All subjects were treated with at-home bleaching using 22% carbamide peroxide (CP) in individual trays for 1 h per day, during 14 days. The color was evaluated before bleaching (D0-baseline), and one day (D1), 15 days (D15), and one month (D30) after bleaching. The color coordinates were measured using the VITA Easyshade™ spectrophotometer and the whiteness index (WID- Whiteness Index for Dentistry) and color differences (ΔE00) for S and NS at different times were calculated. Color changes between S and NS subjects for specific teeth (CI- Central Incisors, LI- Lateral Incisors, and C- Canines) were analyzed using Mann-Whitney test (α=0.05).ResultsThere was no significant difference of WID between S and NS subjects at baseline (D0). NS participants showed higher WID than S at D1, D15, and D30 (p < 0.05). NS showed higher ΔWID for CI and C between D0 and the other evaluation times (D1, D15, and D30) compared to S. Smokers showed higher darkening of CI than NS in ΔWID D30-D1 (p < 0.05). Color change (ΔE00) findings had the overall behavior similar to ΔWID. ΔWID and ΔE00 values for all evaluation times were within the acceptability threshold.ConclusionAlthough smoking showed some effects on the at-home bleaching treatment using 22% CP, teeth whiteness and color changes are clinically acceptable for both groups. Clinical significance: At-home bleaching is a widely performed treatment, however there is a lack of evidence using 22% carbamide peroxide gel in smokers. Although the central incisors showed significant darkening (lower WID) in smokers at 30 days after bleaching, the whitening index was considered clinically acceptable.