35% phosphoric acid modified by available primers may preserve bond strength on long term

Abstract

The aim of this study was to investigate the effect of immediate and on long term dentin bond strength of a universal adhesive in the mode of etch-and rinse, using as conditioner 35% phosphoric acid modified by addition of current primers. Thirty humans’ non carious third molarswere randomly assigned to 3 groups according acid etching used: PA1 - Phosphoric acid (no modification), PA2– Phosphoric acid added 10% of Scotchbond Multi Purpose Primer and PA3– Phosphoric acid added 10% of Vitro Fill LC Primer. The adhesive system used is the Single Bond Universal (3M ESPE, St Paul, MN, USA), on the mode of etch-and rinse. Composite resin restorations were built and sectioned to obtain bonded sticks to be subjected to microtensile (μTBS) testing, one half of the samples were tested after 24 hrs and the other half after 6 monthsof distilled water – long term. The data were analyzed for normality and equal variances using Kolmogorov–Smirnov and submitted to one-way ANOVA at significance level of 5%. Tukey’ s test was applied for multiple comparisons. The data showed that PA1 and PA2 did not have statistic differences, while PA3positively affected the bond strength.The 35% PA modified by 10% of Vitro Fill LC primer showed to be a way to increase bond strength on long term, but addition of primers in the 35% PA gel did not interfere on the expected conditioned aspect of dentin.