Evaluation of the effect of adding fluorescent agent (Rhodamine B) in non-simplified adhesive systems.

Abstract

Rhodamine B is a fluorescent dye commonly used in dentistry for assessing several aspects of adhesive restorations over confocal laser scanning microscopy. By adding rhodamine in adhesive systems, it is possible to apprise characteristics of resin components distribution throughout previously demineralized dentin (the hybrid layer micromorphology, extent and amount of resin tags and adhesive layer thickness) as well as detecting potential defects or changes in adhesive interface (Griffiths, 1999; Walter et al, 2008; Ding et al, 2010; Sampaio et al, 2011). However, dental field literature reveals lack of methodological agreement on dye dissolution in bonding systems (D'Alpino et al, 2006a). The current study intends to estimate the serviceable rhodamine B concentration in simplified bonding systems regarded as gold standard in their categories: Adper" Scotchbond" Multi-Purpose (MP) - etch-and-rinse three steps- and Clearfil" SE Bond (CSE) - a self-etching two steps, considering the null hypotheses that there is no significant difference in tensile bond strength after addition of rhodamine B in concentrations to be determined during the experiment itself, according to each adhesive system evaluated, and that there is no difference in tensile bond strength over time, due to these treatments for such bonding systems. Stage A - Determination of the proportion between rhodamine B mass and adhesive/primer volumes, according to the adhesive system over assessment, since it is enough for full viewing the dye in prepared specimens under microscopic evaluation. Stage B - Using the concentration values determined in previous stage, other properties are intended to be evaluated, especially, the tensile bond strength of adhesive to dentin in specimens prepared for micro-tensile bond test. Stage C - Evaluation of sorption and solubility of MP and CSE's bond components, subjecting them to cycling and desiccation. Micro-tensile bond test results will be correlated with analysis of variance (ANOVA) and paired t-test for each bonding system. In addition, the specimens fractured during micro-tensile bond test will be qualitatively analyzed in scanning electron microscope for determining the fracture types. Results obtained with sorption and solubility procedures will be analyzed through one-way analysis of variance, if there is normal distribution of data, and Tukey's test. Significance level of 5% is considered.