Effect of carbamide peroxide and bromelain bleaching agents by the activation of diode laser on the tooth at different time intervals: An in vitro study

Abstract Objective: To evaluate and compare the peroxide and nonperoxide organic bleaching agents with and without 940 nm diode laser activation on the tooth at different time intervals. Materials and Methods: An in vitro study was conducted on 56 extracted human teeth. Following polishing, specimens were standardized by immersion in black tea solution for 1 week to achieve uniform discoloration. Initial and subsequent shade assessments were performed using a spectrophotometer based on the Commission Internationale de l’Eclairage Lab* system. Teeth were randomly divided into two groups: 10% carbamide peroxide (CP) and bromelain. Each group was further subdivided into four subgroups: Control, gel-only, gel + laser for 2.5 min, and gel + laser for 5 min. Bleaching procedures were performed in two sessions, 1 week apart, with repeated gel applications per session. Color changes were calculated and statistically analysed using the one-way ANOVA with Tukey’s post hoc test ( P < 0.05). Results: Both bleaching agents produced perceptible shade improvements, influenced by diode laser activation and exposure time. Progressive shade enhancement was observed across evaluation points, with some groups showing more stable and pronounced outcomes. Shade relapse varied among protocols, indicating treatment-dependent differences in color stability. Conclusion: Diode laser activation improved the bleaching efficacy of both CP and bromelain systems. Shorter laser exposure proved safer and more effective than prolonged activation. Bromelain demonstrated potential as a biologically friendly alternative to peroxide agents. These findings support incorporating diode lasers into bleaching protocols and encourage further clinical research to validate and standardize treatment strategies.