Effect of bleaching on shear bond strength of orthodontic brackets

ABSTRACT

The purpose of this in vitro study was to determine the effect of bleaching on shear bond strength of orthodontic brackets. This randomized control trial was performed over a period of 6 months in the department of orthodontics, de,Montmorency College of Dentistry, Lahore. A total of one hundred and forty extracted premolar teeth were included which were further divided into two groups. Group A was assigned as control group without bleaching and Group B as study group with bleaching. The teeth in both groups were embedded individually in acrylic placed in rubber moulds using a mounting jig so that the labial surfaces would be parallel to the applied force during the shear test. Group B was bleached with Pola office advanced tooth whitening system and were stored in a solution of 0.9% saline till they were bonded. The bonding process for both groups was then performed in a standard manner. After bonding bracket was properly positioned on its respective tooth. An occluso-gingival load was applied to the bracket producing a shear force at the bracket tooth interface using a computerized shear bonding testing machine. The results showed that there was no statistically significant difference between the shear bond strength of unbleached teeth and that of bleached teeth following a two weeks interval after bleaching