Objectives: The objective of this study was to compare the 5-year clinical performance in posterior restorations of three restorative systems including a low-shrinkage system and a methacrylate-based composite combined either with an etch-and-rinse or a self-etch adhesive.
Materials and methods: Each of 25 patients received three class I (occlusal) or class II restorations performed with each one of the three restorative systems: Filtek Silorane Restorative System including a two-step self-etch adhesive, Adper Scotchbond 1 XT (two-step etch-and-rinse adhesive) + Filtek Z250, and Adper Scotchbond SE (two-step self-etch adhesive) + Filtek Z250. All materials were applied as per manufacturer's instructions. Two blind observers evaluated the restorations at four different moments (baseline, after 1, 2, and 5 years) according to the USPHS-modified criteria. Kruskal-Wallis and Mann-Whitney U tests were conducted to compare the behavior of the restorative systems, while Friedman and Wilcoxon tests were applied to analyze the intrasystem data (p < 0.05).
Results: After 5 years, marginal staining around the restorations with Adper Scotchbond SE + Filtek Z250 was statistically more frequent and severe than that of the restorations performed with the other two systems. Intrasystem comparisons revealed a deterioration of the marginal adaptation after 5 years for all systems. A significant number of restorations bonded with self-etch adhesives showed marginal staining after 5 years of clinical service. A deterioration of the color appearance and an increase of the surface roughness were also detected in the restorations performed with Adper Scotchbond SE + Filtek Z250.
Conclusions: A deterioration of the marginal adaptation was evidenced for all restorative systems, while marginal staining was more frequently seen only around the restorations performed with self-etch adhesives.
Clinical relevance: No advantage was found of the silorane- over the methacrylate-based composite when combined with an etch-and-rinse adhesive.
Keywords: Clinical evaluation; Etch-and-rinse adhesive; Low-shrinkage; Posterior restorations; Self-etch adhesive; Silorane.