• Fawzy, Amr
• Mahmoud, Salah H.
• Elkaffas, Ali A.
• Hamama, Hamdi H.

Abstract

<p>Background: Nowadays, most of the dental manufacturers claimed that ‘Universal’ or ‘multi-mode’ adhesives in self-etch technique can obtain good bonding results comparing to etch-and-rinse or selective etching application techniques. The rationale behind this study was that a multi-mode adhesive, when proven to be effective, would enable general practitioners to apply the adhesive using either an ‘etch-and-rinse’ or an ‘self-etch’ adhesive mode strategy, basically depending on their interpretation of what appears to be most appropriate upon examination of the actual cavity and the overall restoration conditions. Objective: This study examined the effect of acid etching on microtensile bond strength (μTBS), micromorphological patterns of resin-dentin interface using scanning electron microscope (SEM) and SEM of tracer-infused water-rich zones within the hybrid layers of ultra-mild self-etch adhesives bonded to coronal dentin. Methods: Sixty extracted permanent molars were assigned into six groups based on μTBS (n = 10). The groups were bonded with Adper single bond (SB) plus adhesive in etch-and-rinse mode and Adper easy one (EO) bond in self-etch mode as controls; Single Bond Universal self-etch (SUSe) and etch-and-rinse (SUEr); Adhese Universal self-etch (AUSe) and etch-and-rinse (AUEr). The bonded specimens were stored in deionized water for 24 h. Composite/dentin beams were prepared (1 mm²). μTBS testing was performed. Micromorphological evaluation of extra teeth from each study group was conducted using SEM, and nanoleakage (NL) was evaluated. μTBS data were statistically analyzed using two-way ANOVA and multiple comparison post-hoc tests. Results: AUEr had the highest μTBS (p &lt; 0.05). There was a significant difference in μTBS between AUEr and AUSe (p &lt; 0.05). No significant difference was found in μTBS between SUSe and SUEr (p &gt; 0.05). The μTBS for SUEr was similar to the SB control adhesive (p &gt; 0.05), while the μTBS for SUSe was higher than the EO control adhesive (p &lt; 0.05). A comparison of both materials showed that the μTBS was significantly higher for AUEr than SBEr (p &lt; 0.05). The thickness of the hybrid layers created by these adhesives in the etch-and-rinse mode and the self-etch mode were approximately ~5 mm and ≤0.5 mm, respectively. Silver nitrate infused regions were identified within the resin-dentin interface in all the bonded specimens. Conclusion: Application of an etching step prior to water-based adhesive improves its dentin penetration, but it does not affect its μTBS; while application of an etching step prior to ethanol-based adhesive improves its dentin penetration and its μTBS.</p>

Topics

• silver
• scanning electron microscopy
• strength
• composite
• etching
• resin