Effects of thermal cycling on bonding properties of novel low-shrinkage resin adhesive.

抄録

OBJECTIVES: The current study aimed to investigate the bonding properties of a novel low-shrinkage resin adhesive containing expanding monomer and epoxy resin monomer after thermal cycling aging treatment.

METHODS: Expanding monomer of 3,9-diethyl-3,9-dimethylol-1,5,7,11-tetraoxaspiro-[5,5] undecane (DDTU) as an anti-shrinkage additive and unsaturated epoxy monomer of diallyl bisphenol A diglycidyl ether (DBDE) as a coupling agent were synthesized. A blend of DDTU and DBDE at a mass ratio of 1∶1, referred to as "UE", was added into the resin matrix at the mass fraction of 20% to prepare a novel low-shrinkage resin adhesive.Then, the methacrylate resin adhesive without UE was used as the blank control group, and a commercial resin adhesive system was selected as the commercial control group. Moreover, the resin-dentin bonding and micro-leakage testing specimens were prepared for the thermal cycling aging treatment. The bonding strength was tested, the fracture modes were calculated, the bonding fracture surface was observed by scanning electron microscope (SEM), and the dye penetration was used to evaluate the tooth-restoration marginal interface micro-leakage. All the data were analyzed statistically.

RESULTS: After aging, the dentin bonding strength of the experimental group was (19.20±1.03) MPa without a significant decrease (>0.05), that of the blank control group was (11.22±1.48) MPa with a significant decrease (<0.05) and that of the commercial control group was (19.16±1.68) MPa without a significant decrease (>0.05). The interface fracture was observed as the main fracture mode in each group after thermal cycling by SEM. The fractured bonding surfaces of the experimental group often occurred on the top of the hybrid layer, whereas those of the blank and commercial control groups mostly occurred on the bottom of the hybrid layer. Micro-leakage rating counts of specimens before and after thermal cycling were as follows: the experimental group was primarily 0 grade, thereby indicating that a relatively ideal marginal sealing effect could be achieved (>0.05); meanwhile, the blank control group was primarily 1 grade, and the penetration depth of dye significantly increased after thermal cycling (<0.05); the commercial control group was primarily 0 grade without statistical difference before and after thermal cycling (>0.05), while a significant difference was observed between the commercial control group and experimental group after thermal cycling (<0.05).

CONCLUSIONS: The novel low-shrinkage resin adhesive containing 20%UE exhibited excellent bonding properties even after thermal cycling aging treatment, thereby showing a promising prospect for dental application.

: 探讨冷热循环老化处理后，含膨胀单体和不饱和环氧树脂单体新型低收缩树脂粘接剂粘接性能的变化，为后续研究提供依据。: 合成膨胀单体3, 9-二乙基-3, 9-二羟甲基-1, 5, 7, 11-四氧杂螺-[5, 5]十一烷（DDTU）作为抗收缩添加剂，合成不饱和环氧树脂单体二烯丙基双酚A二缩水甘油醚（DBDE）作为增容偶联相，两者（UE）按质量比例1∶1混匀后，以20%比例添加到自行合成的树脂粘接剂中，作为新型低收缩树脂粘接剂实验组，未添加UE的树脂粘接剂作为空白对照组，选取一款全酸蚀树脂粘接系统作为商品对照组。制作树脂-牙本质粘接试件及微渗漏测试试件，进行冷热循环（5 ℃/55 ℃水浴，5 000次）老化处理。测试粘接强度、分析断裂模式及观察粘接断面微观形貌；采用染料渗透法评估修复体边缘微渗漏情况。实验结果进行统计学分析。: 冷热循环处理后，实验组粘接强度为（19.20±1.03）MPa，与处理前相比未见明显降低（>0.05）；空白对照组粘接强度为（11.22±1.48）MPa，与处理前相比明显降低（<0.05）；商品对照组粘接强度为（19.16±1.68）MPa，与处理前相比未见明显降低（>0.05）。扫描电镜观察到冷热循环后各组试件均以界面破坏为主，实验组粘接断面多在混合层顶部，空白对照组和商品对照组粘接断面多在混合层底部。冷热循环前、后微渗漏评级：实验组主要为0级，不受老化影响，能够实现较为理想的边缘封闭效果（>0.05）；空白对照组主要为1级，但冷热循环后染料渗入深度明显增加（<0.05）；商品对照组主要为0级，冷热循环后染料渗入深度未见明显增加（>0.05），但与冷热循环后的实验组差异有统计学意义（<0.05）。: 冷热循环老化处理后，含20%UE的新型低收缩树脂粘接剂仍具有良好的粘接性能，为进一步临床应用奠定了基础。.