• Brandt, William Cunha
• Sinhoreti, Mario Alexandre Coelho
• Silva, Isaias Donizeti
• Vitti, Rafael Pino
• Guarda, Maurício Bottene

Abstract

<p>This study aimed to evaluate the effect of the electric current direction application on the resin composite-dentin bond strength using three adhesive systems. Human molar teeth were distributed according to the adhesive system (two-step self-etch - Clearfil SE Bond, Kuraray [CSE]; one-step self- etch - Single Bond Universal, 3M ESPE [SBU]; and two-step etch-and-rinse - Adper Single Bond 2, 3M ESPE [SB2]), electric current direction (without electric current - control, direct and reverse electric currents - 35μA), and storage time (24h - immediate and 6 months). Resin composite blocks (Filtek Z350XT, 3M ESPE) were bonded to dentin. The teeth/resin composites specimens were stored in distilled water at 37°C for 24 hours and 6 months for the microtensile bond strength (μTBS) test (n = 10; ~ 12 sticks for each tooth). Failure patterns were analyzed on a stereomicroscope and classified as cohesive-dentin, cohesive-resin, adhesive or mixed. Adhesive penetration into dentin and hybrid layer formation were evaluated in a scanning electron microscope (n = 6). Data were submitted to a three-way ANOVA followed by Tukey’s post hoc test (α = 0.05). There are no differences in μTBS when the adhesive systems were applied under direct and reverse electric currents, but both electric currents increased the μTBS for all adhesive systems. SBU showed the lowest μTBS values for control groups in both storage times and direct electric current in 6 months of storage. The adhesive failure pattern was more frequently observed in all groups. The electric current formed long resin tags for all adhesive systems. Storage for 6 months did not significantly decrease μTBS values. Both directions of electric current (positive and negative charges) at 35μA can increase the μTBS of the adhesive systems tested to dentin.</p>

Topics

• strength
• composite
• resin