The effects of ozone gas application on shear bond strength of orthodontic brackets to enamel.

Purpose: To investigate the possibility that ozone may have an adverse effect on the bond strength of orthodontic brackets and to determine the area of residual adhesive on teeth after the debonding of brackets.

Methods: 60 extracted premolars teeth were used in this study. Resin coated APC brackets (3M) were bonded according to the manufacturers' instructions. Bonded teeth were randomly divided into two groups. The teeth in Group 1 were subjected to a 10-second dosage of ozone from the HealOzone unit (Kavo) after etching and to a further 10 seconds of ozone after bonding the brackets using a 5 mm delivery cup. Teeth in Group 2 were used as a control. Debonding was carried out using a testing instrument at a cross-head speed of 1 mm/minute.

Results: The Mann-Whitney test revealed no significant differences in shear bond strength between the two groups (P = 0.337). The mean shear bond strength (11.66 MPa) of Group 1 (subjected to ozone) was not significantly different than the mean shear bond strength (10.88 MPa) of Group 2 (not subjected to ozone). A Pearson Chi-square test of the Adhesive Remnant Index (ARI) revealed no significant difference in residual adhesive among the groups tested.