New protective polish effects on shear bond strength of brackets

One of the solutions for the problem of white spot lesions has been the application of a polymer coating to the labial enamel surface. The aim of this study is to find out whether the liquid polish BisCover affects the bond strength of brackets bonded with a light-cured system (Transbond XT) and a no-mix system (Unite). Standard stainless steel premolar brackets were bonded to 100 permanent human premolars randomly divided into five equal groups. Two different enamel surface conditions were studied: dry and varnished with BisCover. For each enamel surface condition, two orthodontic adhesive systems were used: a light-cured system (Transbond XT) and a no-mix system (Unite). All teeth were conditioned with 37% phosphoric acid for 30 seconds, followed by thorough washing and drying. The teeth in groups 1 and 2 were bonded with Transbond XT and Unite, respectively. For groups 3, 4, and 5, a thin layer of BisCover was applied to the etched enamel with a brush and light cured for 15 seconds. In group 3, a thin layer of Transbond XT primer was applied, whereas in group 5, no additional primer was used on BisCover. In groups 3 and 5, the brackets were bonded with Transbond XT adhesive resin. Group 4 was bonded with no-mix Unite. Shear forces were applied to the samples by a Zwick Universal test machine, and bond strengths measured in megapascals. The results revealed that shear bond strengths of the groups did not differ significantly from each other.