Deng Donglai, Yang Hongye, Guo Jingmei, Chen Xiaohui, Zhang Weiping, Huang Cui
The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory for Oral Biomedical Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China.
Lanzhou Hospital of Stomatology, Lanzhou, China.
J Dent. 2014 Dec;42(12):1577-85. doi: 10.1016/j.jdent.2014.09.010. Epub 2014 Sep 23.
To compare the effects of four commonly used artificial ageing methods (water storage, thermocycling, NaOCl storage and pH cycling) on the degradation of adhesive-dentine interfaces.
Fifty molars were sectioned parallel to the occlusal plane, polished and randomly divided into two adhesive groups: An etch-and-rinse adhesive Adper SingleBond 2 and a self-etch adhesive G-Bond. After the composite built up, the specimens from each adhesive group were sectioned into beams, which were then assigned to one of the following groups: Group 1 (control), 24h of water storage; Group 2, 6 months of water storage; Group 3, 10,000 runs of thermocycling; Group 4, 1h of 10% NaOCl storage; and Group 5, 15 runs of pH cycling. The microtensile bond strengths were then tested. The failure modes were classified with a stereomicroscope and representative interface was analyzed with a field-emission scanning electron microscopy (FESEM). Nanoleakage expression was evaluated through FESEM in the backscattered mode.
The four artificial ageing methods decreased the bonding strength to nearly 50% and increased the nanoleakage expression of both adhesive systems compared with the control treatment. Adhesive failures were the predominant fracture modes in all groups. However, differences in detailed morphology were observed among the different groups.
Water storage, thermocycling, NaOCl storage and pH cycling could obtain similar degradation effectiveness through appropriate parameter selection. Each in vitro artificial ageing method had its own mechanisms, characteristics and application scope for degrading the adhesive-dentin interfaces.
Water storage is simple, low-cost but time-consuming; thermocycling lacks of a standard agreement; NaOCl storage is time-saving but mainly degrades the organic phase; pH cycling can resemble cariogenic condition but needs further studies. Researchers focusing on bonding durability studies should be deliberate in selecting an appropriate ageing model based on the differences of test material, purpose and time.
比较四种常用人工老化方法（水储存、热循环、次氯酸钠储存和pH循环）对粘结剂-牙本质界面降解的影响。
将50颗磨牙沿咬合面平行切片，抛光后随机分为两组粘结剂组：酸蚀冲洗粘结剂Adper SingleBond 2和自酸蚀粘结剂G-Bond。复合树脂充填后，将每组粘结剂的标本切成梁状，然后分为以下几组：第1组（对照组），水储存24小时；第2组，水储存6个月；第3组，10000次热循环；第4组，10%次氯酸钠储存1小时；第5组，15次pH循环。然后测试微拉伸粘结强度。用体视显微镜对断裂模式进行分类，并用场发射扫描电子显微镜（FESEM）分析代表性界面。通过FESEM在背散射模式下评估纳米渗漏表达。
与对照处理相比，四种人工老化方法使两种粘结系统的粘结强度降低至近50%，并增加了纳米渗漏表达。粘结剂断裂是所有组中的主要断裂模式。然而，不同组之间观察到详细形态的差异。
通过适当选择参数，水储存、热循环、次氯酸钠储存和pH循环可获得相似的降解效果。每种体外人工老化方法在降解粘结剂-牙本质界面方面都有其自身的机制、特点和应用范围。
水储存简单、成本低但耗时；热循环缺乏标准共识；次氯酸钠储存省时但主要降解有机相；pH循环可模拟致龋条件但需要进一步研究。专注于粘结耐久性研究的研究人员应根据测试材料、目的和时间的差异，慎重选择合适的老化模型。
