Comparison of dental bleaching effects of ozone and hydrogen peroxide: An ex vivo study.

Purpose: To compare the efficacy of using ozone versus hydrogen peroxide (H2O2) for tooth bleaching.

Methods: 90 extracted teeth were allocated into two groups. Teeth in Group 1 (n= 45) were exposed to ozone for 60 seconds; ozone was produced by healOzone x4 machine (healOzone x4), and was applied to teeth through special disposable silicone cups. The silicone cups allowed total seal and avoided gas escape as the machine is devised to work only if the cup guarantees perfect seal and thus secure the safety of the machine for human use. Teeth in Group 2 (n= 45) were treated with 38% H2O2 for 20 minutes. The shade of teeth was recorded for both groups at base line, after application of ozone in Group 1, and after application of H2O2 in Group 2. The reading for L* a* b* values and Vita Classic shades were recorded using the Colorimeter Konica-Minolta CR-400. The statistically significant differences were set at P≤ 0.05.

Results: The teeth in both groups acquired lighter shades after bleaching (P< 0.001). In addition, baseline L* shade values were increased and b* shade values were decreased (means lighter shades) after bleaching in both groups (P< 0.01). However, baseline a* shade values were not significantly changed after bleaching with ozone in Group 1 (P= 0.682). In contrast, a* shade values were significantly decreased after bleaching with H2O2 in Group 2 (P= 0.005). Furthermore, final shades achieved after bleaching were not significantly different between groups (P> 0.05). In conclusion, application of ozone for 60 seconds or application of 38% of H2O2 for 20 minutes resulted in teeth with lighter shades. Bleaching by application of ozone for 60 seconds would result in similar outcomes to bleaching with 38% H2O2.

Clinical Significance: This is the first study to compare bleaching effects of ozone and hydrogen peroxide on natural human teeth. It might be suitable to consider ozone for dental bleaching since comparing to H2O2 it could potentially reduce the time, side effects and cost of treatment. Also, application of ozone is better controlled and more convenient and measurable as it is delivered by a machine that can manage the concentration, volume, delivery site and timing of delivered ozone.