Color assessment after bleaching with hydrogen peroxide versus ozone: a randomized controlled clinical trial.

This randomized controlled clinical trial evaluated the color change of teeth bleached with either hydrogen peroxide (HP) or ozone (OZ). A total of 26 patients with a mean age of 36.2 years (SD, 8.7 years) who met the inclusion criteria were enrolled in the study. The subjects were randomly assigned to receive chairside bleaching using 40% HP or gaseous OZ. Maxillary dental arch vacuum trays were constructed with circumferential openings in the middle portion of the maxillary incisors at their labial surfaces. These trays were used for measuring color-first at baseline and then immediately and 48 hours after postbleaching-and were not used in bleaching. Changes in color were determined using CIE L*a*b* coordinates. Analysis of the data revealed that, while overall color change (ΔE*) values of the HP and OZ groups did not show statistically significant differences immediately after bleaching (P = 0.114), ΔE* values were significantly different 48 hours postbleaching (P = 0.00). Visible color changes were not obtained with either HP or OZ immediately postbleaching. The greatest visible color change occurred with HP 48 hours postbleaching.

Antibacterial efficacy of prophylactic ozone treatment on patients with fixed orthodontic appliances.

OBJECTIVE: This study investigated the efficacy of ozone on microflora of patients with fixed orthodontic appliances. MATERIALS AND METHODS: Ten subjects undergoing fixed appliance therapy were enrolled in the study. Before any application, two elastic ligatures were removed with the aid of a sterile probe from the premolar brackets on the upper right and lower left jaws for baseline bacteriological counts. Then ozone gas was applied for 180 s by running the device on prophylaxis mode with included mouth tray according to the manufacturer's recommendations on all brackets. After the ozone application, two other elastic ligatures were removed from the opposite sides of the mouth of the patients. One week after the application two more elastic samples, which were not changed in the previous session, were collected from the upper right and lower left premolar brackets. The elastic ligatures were immersed in transfer solutions and cultured to determine the Streptococcus mutans and Lactobacillus acidophilus. Statistical analysis of the data was obtained by paired Student's t-tests. RESULTS: The ozone treatment reduced the S. mutans and L. acidophilus immediately after the application and these reductions were found to be statistically significant (p = 0.038 and p = 0.020). Both the S. mutans and L. acidophilus values increased by the 1-week period and the S. mutans values were significantly higher than the baseline values (p = 0.01). CONCLUSION: It can be concluded that the ozone treatment may have an instantaneous lethal effect on S. mutans and L. acidophilus; however, within the limitations of this study, a long-term preventive effect could not be observed.