Influence of saliva contamination on the shear bond strength of orthodontic brackets bonded with self-etching adhesive systems

IntroductionOur objective was to evaluate the influence of saliva contamination on the shear bond strength of orthodontic brackets bonded with self-etching primers.MethodsOne hundred thirty-five bovine incisors were randomly divided into 3 groups, and exposed enamel surfaces were bonded with Transbond Plus Self Etching Primer (TB) (3M Unitek, Monrovia, Calif), Adhese Single Bottle (AD) (Ivoclar, Vivadent, Schaan, Liechtenstein), and Self Etch Bond (SE) (Vigodent, Rio de Janeiro, Brazil). Each group was subdivided into 3 treatments (n = 15): saliva contamination (S), saliva contamination and deionized water rinsing (SW), and no salivary contamination (C). Resin composite (Z-100, 3M/ESPE, Salt Lake City, Utah) was applied to all samples to bond the orthodontic brackets. Shear bond strength testing was carried out in a universal testing machine operating at 1.0 mm per minute.ResultsThe results were statistically analyzed with 2-way analysis of variance (ANOVA) and Tukey tests (P <0.05). Saliva contamination caused a significant decrease of enamel strength in the groups bonded with TB and SE compared with the SW and C groups. Enamel bond strengths of the C and SW groups were higher than those of the TB group, followed by the AD and SE groups. Enamel bond strength after S was higher than AD, followed by TB and SE.ConclusionsThe shear bond strengths of orthodontic brackets to enamel and the performance of the adhesive systems were influenced by contamination with saliva.