Effect of caries-affected dentin on one-step universal and multi-step etch-and-rinse adhesives’ bond strength

Abstract Objective To evaluate the influence of caries-affected dentin on bond strength of a universal one-step and a multi-step etch-and-rinse adhesive system. Material and method Enamel of 60 third human molars with and without caries was removed to expose dentin. The teeth were randomly assigned to six groups: Single Bond Universal (3M ESPE, St. Paul, MN, USA) in etch-and-rinse and in self-etch mode and Prime & Bond NT (Dentsply Co, Konstanz, Germany), all on sound and caries-affected dentin. Smear layer of the 30 sound dentin specimens was standardized by polishing with 600-grit SiC paper under water cooling. Residual infected dentin of the 30 caries-affected specimens was removed with a number 4 CA carbide bur until no caries smooth tissue was detectable by tactile-visual inspection. Cylinders of a light cured composite resin (Filtek Z350 XT, 3M ESPE) were built up using starch tubes and microshear test was performed until failure. The data was analyzed by one-way ANOVA and Tukey’s post hoc test. Result Significant differences in microshear bond strength (μSBS) were observed for the caries-affected groups, but not for sound dentin. The μSBS of Single Bond Universal were not influenced by the application protocol on sound dentin, however they were lower in the caries-affected group with both application protocols. The μSBS for Prime & Bond NT was not influenced by the dentin conditions. Conclusion Caries-affected dentin decrease in bond strength of Single Bond Universal in comparison to sound dentin. The bond strength of Prime & Bond NT was not altered by substrate conditions.

摘要 目的：评估龋损牙本质（caries-affected dentin）对通用一步法与多步酸蚀冲洗型粘结系统粘结强度（bond strength）的影响。
材料与方法：选取60颗人类第三磨牙，去除牙釉质以暴露牙本质，将其随机分为6组：分别采用通用粘结剂Single Bond Universal（3M ESPE，美国明尼苏达州圣保罗市）的酸蚀冲洗模式与自酸蚀模式，以及Prime & Bond NT（登士柏公司，德国康斯坦茨市），分别作用于健康牙本质与龋损牙本质。对30份健康牙本质标本，采用600目碳化硅（SiC）砂纸水冷抛光以统一玷污层（smear layer）状态；对30份龋损牙本质标本，使用4号CA硬质合金车针去除残余感染牙本质，直至触诊与目视检查无法检测到龋损组织。采用淀粉管制备光固化复合树脂Filtek Z350 XT（3M ESPE）的圆柱状试件，随后进行微剪切试验直至试件破坏。采用单因素方差分析（one-way ANOVA）与Tukey事后检验（Tukey’s post hoc test）对数据进行统计学分析。
结果：龋损牙本质组的微剪切粘结强度（μSBS，microshear bond strength）存在显著差异，而健康牙本质组未观察到此类差异。Single Bond Universal的粘结强度在健康牙本质上不受应用模式影响，但在两种应用模式下的龋损牙本质组中，其粘结强度均有所降低；Prime & Bond NT的粘结强度则不受牙本质状态的影响。
结论：相较于健康牙本质，龋损牙本质会降低Single Bond Universal的粘结强度；而Prime & Bond NT的粘结强度不受牙本质底物状态的改变影响。