Department of Biomedical and Neuromotor Sciences, DIBINEM, University of Bologna - Alma Mater Studiorum, Via San Vitale 59, 40125 Bologna, Italy.
Department of Restorative Dentistry, School of Dentistry, University of São Paulo, Av. Prof. Lineu Prestes 2227, 05508-000 São Paulo, Brazil.
J Dent. 2019 Jun;85:25-32. doi: 10.1016/j.jdent.2019.04.008. Epub 2019 Apr 15.
This in vitro study evaluated at baseline (T0) and over time (T12 months), the effect of a multi-mode universal adhesive compared with two experimental formulations blended with different concentrations of benzalkonium chloride (BAC), on bond strength and endogenous enzymatic activity.
Specimens were assigned to the following groups according to the adhesive protocol: G1) All-Bond Universal (ABU) self-etch (SE); G2) ABU + 0.5% BAC SE; G3) ABU + 1% methacrylate BAC SE; G4) ABU etch-and-rinse (E&R); G5) ABU + 0.5% BAC E&R; G6) ABU + 1% methacrylate BAC E&R. Gelatin zymography was performed on dentin powder obtained from eight human third molars. Endogenous enzymatic activity within the hybrid layer was examined using in situ zymography after 24 h (T0) or 1-year storage in artificial saliva (T12). Forty intact molars were prepared for microtensile bond strength test at T0 and T12. Results were statistically analyzed with three-way ANOVA (α = 0.05).
Gelatin zymography assay and in situ zymography quantification analyses indicated that all the BAC-containing formulations decreased matrix metalloproteinase expression. However, in situ zymography showed a general trend of enzymatic activity increase after aging. Microtensile bond-strength testing showed decrease in bond strength over time in all the tested groups; performances of the 1% methacrylate BAC experimental groups were worse than the control.
BAC-containing adhesives reduce endogenous enzymatic activity both immediately and over time. However, independently from the adhesive employed, increase in the gelatinolytic activity over time and decrease in bond strength was found (especially in the BAC + 1% methacrylate groups), probably due to impaired polymerization properties.
Adhesives containing protease inhibitors are practical and efficient tools in clinical practice for enhancement of the longevity of dental restorations. However, extensive investigation of the mechanical and adhesive properties of the material is necessary prior to their clinical use.
本体外研究评估了一种多模式通用胶粘剂与两种不同浓度苯扎氯铵（BAC）混合的实验制剂在基线（T0）和 12 个月时（T12 个月）对粘结强度和内源性酶活性的影响。
根据粘结方案，将标本分为以下组：G1）All-Bond Universal（ABU）自酸蚀（SE）；G2）ABU+0.5% BAC SE；G3）ABU+1%甲基丙烯酰基 BAC SE；G4）ABU 酸蚀-冲洗（E&R）；G5）ABU+0.5% BAC E&R；G6）ABU+1%甲基丙烯酰基 BAC E&R。从 8 个人类第三磨牙中获得牙本质粉进行明胶凝胶电泳。在 24 小时（T0）或在人工唾液中储存 1 年后（T12），通过原位酶谱法检查混合层内的内源性酶活性。在 T0 和 T12 时，对 40 个完整的磨牙进行微拉伸粘结强度测试。用三因素方差分析（α=0.05）对结果进行统计学分析。
明胶凝胶电泳分析和原位酶谱定量分析表明，所有含 BAC 的制剂均降低了基质金属蛋白酶的表达。然而，原位酶谱显示老化后酶活性普遍增加的趋势。微拉伸粘结强度测试表明，所有测试组的粘结强度随时间的推移而降低；1%甲基丙烯酰基 BAC 实验组的性能比对照组差。
含 BAC 的胶粘剂可立即和随时间降低内源性酶活性。然而，无论使用何种胶粘剂，随时间的推移都会发现明胶水解活性增加和粘结强度降低（尤其是在 BAC+1%甲基丙烯酰基组中），这可能是由于聚合性能受损所致。
含有蛋白酶抑制剂的胶粘剂是临床实践中增强牙科修复体耐久性的实用且有效的工具。然而，在临床使用之前，必须对材料的机械和粘结性能进行广泛的研究。
