Department of Restorative Sciences, Division of Operative Dentistry, University of Minnesota School of Dentistry, 515 SE Delaware St., 8-450 Moos Tower, Minneapolis, MN 55455, USA.
Dent Mater. 2010 Feb;26(2):e24-37. doi: 10.1016/j.dental.2009.11.149. Epub 2009 Dec 14.
The wetness of dentin surfaces, the presence of pulpal pressure, and the thickness of dentin are extremely important variables during bonding procedures, especially when testing bond strength of adhesive materials in vitro with the intention of simulating in vivo conditions. The ultimate goal of a bonded restoration is to attain an intimate adaptation of the restorative material with the dental substrate. This task is difficult to achieve as the bonding process is different for enamel and for dentin-dentin is more humid and more organic than enamel. While enamel is predominantly mineral, dentin contains a significant amount of water and organic material, mainly type I collagen. This humid and organic nature of dentin makes this hard tissue very challenging to bond to. Several other substrate-related variables may affect the clinical outcome of bonded restorations. Bonding to caries-affected dentin is hampered by its lower hardness and presence of mineral deposits in the tubules. Non-carious cervical areas contain hypermineralized dentin and denatured collagen, which is not the ideal combination for a bonding substrate. Physiological transparent root dentin forms without trauma or caries lesion as a natural part of aging. Similar to the transparent dentin observed underneath caries lesions, the tubule lumina become filled with mineral from passive chemical precipitation, making resin hybridization difficult. An increase in number of tubules with depth and, consequently, increase in dentin wetness, make bonding to deeper dentin more difficult than to superficial dentin. While the application of acidic agents open the pathway for the diffusion of monomers into the collagen network, it also facilitates the outward seepage of tubular fluid from the pulp to the dentin surface, deteriorating the bonding for some of the current adhesives. Some dentin desensitizers have shown some promise as they can block dentinal tubules to treat and prevent sensitivity and simultaneously blocking the tubular fluid from flowing to the surface. A new approach to stop the degradation of dentin-resin interfaces is the use of MMP inhibitors. Although still in an early phase of in vitro and clinical research, this method is promising.
牙本质表面的湿润程度、牙髓压力的存在以及牙本质的厚度在粘接过程中是极其重要的变量，特别是在体外测试粘接材料的粘接强度以模拟体内条件时。粘接修复的最终目标是使修复材料与牙体组织达到紧密的适应。然而，由于牙本质的粘接过程与牙釉质不同，牙本质比牙釉质更湿润且更具有机物特性，所以这一任务非常具有挑战性。牙釉质主要由矿物质组成，而牙本质含有大量的水分和有机物，主要是 I 型胶原蛋白。牙本质的这种湿润和有机物特性使得这种硬组织很难与之结合。其他一些与基底相关的变量可能会影响粘接修复的临床效果。由于牙本质硬度降低以及管内有矿物质沉积，龋坏牙本质的粘接受到阻碍。非龋性颈段区域含有过度矿化的牙本质和变性胶原蛋白，这并不是理想的粘接基底组合。生理性透明根牙本质在没有创伤或龋病病变的情况下形成，是衰老的自然组成部分。与观察到的龋病病变下的透明牙本质相似，管腔的管腔变得充满了来自被动化学沉淀的矿物质，使得树脂杂交变得困难。随着深度的增加，管腔数量增加，牙本质湿润度增加，使得与深层牙本质的粘接比与浅层牙本质的粘接更困难。虽然酸性剂的应用为单体扩散到胶原蛋白网络中开辟了途径，但它也促进了管状流体从牙髓向牙本质表面的外渗，从而恶化了一些现有胶粘剂的粘接性能。一些牙本质脱敏剂已经显示出一定的前景，因为它们可以阻塞牙本质小管，治疗和预防敏感性，同时阻止管状流体流向表面。阻止牙本质-树脂界面降解的一种新方法是使用 MMP 抑制剂。尽管这种方法仍处于体外和临床研究的早期阶段，但很有前途。
