Randomized controlled clinical trial on bleaching sensitivity and whitening efficacy of hydrogen peroxide versus combinations of hydrogen peroxide and ozone.

The clinical efficacy regarding bleaching sensitivity and tooth shade lightening using a standard hydrogen peroxide (HO) bleaching gel was compared with the additional use of ozone either before or after application of HO. Using computer-generated tables, 45 participants were randomly allocated into three groups (n = 15 each) in this investigator-driven, single-centre trial. In Group 1, upper anterior teeth were bleached using ozone (produced via a healOzone X4 device) for 60 seconds, then 38% HO for 20 minutes; in Group 2, 38% HO application (20 min) was followed by ozone (60 s); air produced by the healOzone machine (60 s) followed by 38% HO (20 min) was used in Group 3 (control). Bleaching sensitivity was evaluated via visual analogue scales, and a treatment-blinded reader objectively recorded tooth shades using a colorimeter before and 24 hours after bleaching (at α = 0.05). The HO/ozone combination did not result in pain sensations, while both ozone/HO and HO alone increased bleaching sensitivity (p < 0.001). Teeth achieved lighter shades (higher L*/lower b* values) after bleaching in all groups (p < 0.001), while Ozone boosted lighter tooth shades, irrespective of its use before or after HO (p < 0.05). Due to the complimentary effects, applying ozone after HO seems preferable for bleaching.