In vitro evaluation of the tooth bleaching efficacy and safety of high-concentration hydrogen peroxide with cold atmospheric plasma.

Background: Using hydrogen peroxide (HP) for tooth bleaching may induce various side effects. Cold atmospheric plasma (CAP) is a promising solution. We aimed to evaluate and compare the efficacy and safety of tooth bleaching using high-concentration HP with CAP with conventional in-office bleaching.

Methods: Fifty-one discolored extracted human teeth were assigned to three groups: Group 1 (light-emitting diode with 35 % HP), Group 2 (CAP with 35 % HP), and Group 3 (only CAP). Bleaching was conducted over three sessions for a total of 20 min. The bleaching effect was evaluated based on the changes in color (ΔE and WI) and lightness (ΔL and ΔG). Safety was assessed by examining the dark areas on the enamel and monitoring the pulp chamber temperature. The study analyzed how different bleaching methods and durations affected ΔE and ΔWI using repeated-measures analysis of variance (ANOVA). The Kruskal-Wallis and Mann-Whitney tests were used for ΔL and dark areas, and one-way ANOVA for ΔG after 20 min of bleaching.

Results: The ΔE and WI demonstrated an interaction based on the bleaching method and time, with Group 1 exhibiting the highest ΔE and WI at all treatment times (p < 0.001). ΔL and ΔG did not differ significantly between Groups 1 and 2 (p = 0.056 and 0.062, respectively) and were lowest in Group 3 (p < 0.001). Group 1 exhibited the darkest areas and highest pulp chamber temperatures (p < 0.001). Group 1 exhibited statistically significant color changes. Group 2 demonstrated similar effects, but with enhanced safety profiles.

Conclusions: Group 2, although displaying a slightly less pronounced color change compared with Group 1, achieved a color alteration readily discernible to the naked eye. This suggests that CAP with 35 % HP could be an interesting area for further investigation as an alternative to traditional in-office bleaching methods.