Vallabhdas Anand K, Kumar C N Vijay, Kabbinale Pradeep, Nayak Rajaram, Rajakumari Manju, Shilpa Thulasidharan
Department of Conservative Dentistry and Endodontics Subbaiah Institute of Dental Sciences, Shimoga, Karnataka India.
Department of Conservative Dentistry and Endodontics Subbaiah Institute of Dental Sciences, Shimoga, Karnataka India, Phone: +919480047110, e-mail:
J Contemp Dent Pract. 2018 Jan 1;19(1):52-59. doi: 10.5005/jp-journals-10024-2211.
Restorative dentists employ different bonding systems between the resin and the dentin and other dentinal tissues to achieve the goal of micromechanical retention. Studies have shown that the bond between composite and dentin degrades over time because of the action of matrix metalloproteinases (MMPs) on collagen fibrils left unprotected by acid etching. The MMPs may be partially responsible for hybrid layer degradation. Since chlorhexidine (CHX) inhibits MMPs, we hypothesized that CHX would decelerate the loss of resin-dentin bonds. Hence, this in vitro study is intended to evaluate the effects of 2% CHX on hybrid layer and bonding interface.
Totally, 40 freshly extracted molars were randomly divided into four experimental groups. In all 40 specimens, class II cavities were prepared to a depth of 1 mm below the dentinoenamel junction with no axial wall, but the elimination of the proximal enamel ridge. The teeth were then randomly divided into four experimental groups, i.e., All Bond 2 without 2% CHX (group I), All Bond 2 with 2% CHX (group II), One Coat 7.0 without 2% CHX (group III), and One Coat 7.0 with 2% CHX (group IV). All the specimens were derooted and sectioned mesiodistally into two halves and placed under water at 37°C for 3 months and observed under scanning electron microscope for the hybrid layer and resin tag formation.
Groups I and II showed statistically significant difference when the presence/absence of resin tags was compared. When groups III and IV were compared for the presence/absence of hybrid layer and resin tags, the results were statistically significant.
Between all the four experimental groups, irrespective of the bonding systems used, we concluded that groups with 2% CHX usage showed promising results with presence/ absence of hybrid layer and resin tags formation.
Studies suggest that the bond between composite and dentin degrades over time because of the action of MMPs on collagen fibrils left unprotected by acid etching. Measures should be taken to prevent this from happening and thus allow bond between composite and dentin last longer.
修复牙医在树脂与牙本质及其他牙本质组织之间采用不同的粘结系统，以实现微机械固位的目标。研究表明，由于基质金属蛋白酶（MMPs）对未被酸蚀保护的胶原纤维的作用，复合树脂与牙本质之间的粘结会随时间降解。MMPs可能是导致混合层降解的部分原因。由于洗必泰（CHX）可抑制MMPs，我们推测CHX会减缓树脂-牙本质粘结的丧失。因此，本体外研究旨在评估2%CHX对混合层和粘结界面的影响。
总共40颗新鲜拔除的磨牙随机分为四个实验组。在所有40个标本中，制备II类洞，洞深至牙本质釉质界下方1mm，无轴壁，但去除近中釉质嵴。然后将牙齿随机分为四个实验组，即不含2%CHX的全粘结2（I组）、含2%CHX的全粘结2（II组）、不含2%CHX的单涂层7.0（III组）和含2%CHX的单涂层7.0（IV组）。所有标本均去根，沿近远中方向切成两半，置于37°C水中3个月，在扫描电子显微镜下观察混合层和树脂突的形成。
比较I组和II组树脂突的有无时，差异具有统计学意义。比较III组和IV组混合层和树脂突的有无时，结果具有统计学意义。
在所有四个实验组中，无论使用何种粘结系统，我们得出结论，使用2%CHX的组在混合层和树脂突形成方面显示出良好的结果。
研究表明，由于MMPs对未被酸蚀保护的胶原纤维的作用，复合树脂与牙本质之间的粘结会随时间降解。应采取措施防止这种情况发生，从而使复合树脂与牙本质之间的粘结持续更长时间。
