Nanoleakage, ultramorphological characteristics, and microtensile bond strengths of a new low-shrinkage composite to dentin after artificial aging

作者：Duarte Sillas Jr^*; Phark Jin Ho; Varjao Fabiana Mansur; Sadan Avishai

来源：Dental Materials, 2009, 25(5): 589-600.

DOI：10.1016/j.dental.2008.10.012

• Microtensile bond strengths
• Nanoleakage
• Dentin adhesion
• Hybrid layer thickness
• Aging
• Silorane
• Scanning electron microscopy

Objectives. To study the microtensile bond strengths and nanoleakage of low-shrinkage composite to dentin. The null hypotheses tested were (1) aging does not affect the bonding of low-shrinkage composite; (2) there is no difference in microtensile bond strengths and nanoleakage using different bonding strategies.
Methods. 32 extracted molars were assigned to one of four groups: LS System Adhesive (LS, 3M ESPE); dentin etched for 15s with phosphoric acid + LS System Adhesive (LSpa); Adper Single Bond Plus (SB, 3M ESPE); SB + LS Bond (SBLS). Occlusal dentin was exposed and restored with Filtek LS (3M ESPE). The samples were tested after 24h or after 20,000 thermocycles and 6 months of aging. Teeth were sectioned with a cross-section of 0.8 +/- 0.2 mm(2) and fractured at a crosshead speed of 1 mm/min. The data were submitted to ANOVA/Duncan's post hoc test, at p < 0.05. Five slabs from each group were selected and immersed in 50 wt% ammoniacal silver nitrate, Then, specimens were processed for SEM, the silver penetration was measured and data analyzed with Kruskal-Wallis at p < 0.05.
Results. No statistically significant difference was found among the experimental groups for the factor dentin treatment (p = 0.165) and aging (p = 0.091). All experimental groups exhibit some degree of nanoleakage. There was no adhesion of Filtek LS applied directly over dentin surfaces treated with SB.
Significance. The new low-shrinkage resin composite showed compatibility only with its dedicated adhesive. Pre-etching did not improve the bond strengths to low-shrinkage resin composite. Some degree of nanoleakage was evident in all groups.

• 出版日期2009-5