离体牙储存方式对牙本质黏结剂微拉伸强度的影响

Influence of storage methods on microtensile bond strength of dentin adhesive system

目的:对比研究不同的离体牙储存方法和时间对牙本质黏结剂Single Bond微拉伸强度的影响。方法:选用30颗因正畸拔除的第一前磨牙,随机分为5组。拔除后立即分别放入4℃的0.02%麝香草酚水溶液、10%甲醛溶液、1%氯胺溶液、蒸馏水中储存,以及用湿纱布包裹-20℃冰箱中储存。分别在储存的第10天、90天取出,在牙冠牙合面表层牙本质上使用牙本质黏结剂Single Bond,复合树脂Z250黏结修复,测定牙本质黏结剂的微拉伸强度值。选用新鲜拔除的前磨牙作为对照组。用体视显微镜和扫描电子显微镜观察微拉伸强度测试样本的断裂类型。用SPSS11.5软件对牙本质黏结剂的微拉伸强度值做双因素方差分析。结果:不同的储存方法对牙本质黏结剂微拉伸强度有显著影响(P=0.01),与新鲜拔除的牙比较,蒸馏水中4℃储存(P=0.024)和0.02%麝香草酚水溶液4℃储存(P=0.008)的离体牙的微拉伸强度显著降低;不同的储存时间对牙本质黏结剂的微拉伸强度影响无统计学差异(P=0.279)。所有微拉伸强度测试样本的断裂均发生在黏结界面。结论:离体牙储存方法对牙本质黏结剂Single Bond的黏结强度有重要影响,建议使用离体牙评价牙本质黏结剂的黏结强度时,选用新鲜拔除的牙、-20℃冷冻的牙或1%氯胺溶液4℃储存的牙,以减小不必要的实验误差。

PURPOSE: To compare the effects of teeth stored with different methods and different durations of storage on the microtensile bond strength of the dentin adhesive system Single Bond. METHODS: 30 human first premolars were stored immediately after extraction in one of five commonly used methods respectively: 0.02% distilled water and thymol, 10% formalin, 1%chloramine, distilled water at 4℃ and were refrigerated at -20℃. After 10 days, 90 days, the dentin adhesive system Single Bond and composite Z250 were applied to superficial occlusal flat dentin according to the manufacturers' instructions and microtensile bond strength measurements were evaluated, freshly extracted teeth being used as control. Stero-microscope and scanning electronic microscope were used to evaluate the fracture modes of the microtensile bond strength specimens. Two-way ANOVA was used for analysis of the microtensile bond strengths among different groups. RESULTS: The results showed that there was significant difference among five tooth storage methods on the microtensile bond strength of dentin bonding agent (P=0.01). Compared with freshly extracted teeth, two of five storage methods/media, 0.02% distilled water and thymol at 4℃(P=0.008) and distilled water at 4℃ (P=0.024), resulted in significantly lower microtensile bond strengths. The duration of teeth storage had no effect on the microtensile bond strength of dentin bonding agent (P=0.279). The interaction of two factors was significant (P=0.000). Stero-microscope and SEM examination indicated that all fracture modes were adhesive failures. CONCLUSIONS: From this study, it can be concluded that the teeth storage methods/media can influence the microtensile bond strength of Single Bond adhesive system. If sufficient numbers of freshly extracted teeth are not available for bond strength test, the freezing teeth at -20℃ and teeth stored in 1%chloramine at 4℃ are preferred .