Reasons for poor durability of resin-dentin bonds

树脂-牙本质粘接耐久性差的原因

• 批准号: 7015622
• 负责人: DAVID H PASHLEY
• 金额: $ 35.04万
• 依托单位: AUGUSTA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-03-01 至 2009-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7015622
• 关键词: biomaterial compatibility; chemical bond; chlorhexidine; collagenase; dental adhesive /sealant; dentin; diphosphonate; electrical impedance; enzyme inhibitors; fluoride ion; human subject; hydropathy; metalloendopeptidases; patient oriented research; physical property; prevention; resin; tooth

DESCRIPTION: The lack of durability of resin-dentin bonds results in enormous health care costs as tooth-colored restorations require frequent replacement due to deteriorating interfacial coupling of resin composites to dentin. Our overall hypothesis is that the lack of durability involves degradation of both the resin and collagen phases of the hybrid layer that creates the interracial coupling. Due to the wet bonding technique, adhesive formulations are more hydrophilic than in the past. Hydrophilic resins in the adhesive promote nonuniform water absorption that creates water-filled voids and channels that accelerate hydrolysis of ester bonds in the polymers. We propose to follow the rate of these processes nondestructively by measuring changes in the electrical impedance of resins. Long-term bonding studies in vitro and in vivo show the loss of collagen from the hybrid layer. Collagen fibrils in the dentin matrix appear to be hydrolyzed in vitro, even in the absence of bacteria, by matrix metalloproteinases (MMPs) that were trapped in the matrix during its formation, and that slowly attack the demineralized collagen fibrils infiltrated with resin. This overall hypothesis will be tested by experiments designed to contrast the stability of hydrophilic versus hydrophobic resins; we will also test the stability of collagen matrices when they are fully demineralized versus when they are bonded to demineralized matrices that are within 10 um of mineralized dentin that can slowly expose more MMPs, or when MMPs in dentin are inactivated by heat or enzyme inhibitors. A variety of inhibitors of MMPs will be tested to determine if they can prevent the loss of the mechanical properties of the matrix that leads to low bond strengths and coupling failures. Hopefully, a nonspecific inhibitor of MMP (e.g. chlorhexidine or bisphosphonates) can be applied as a pretreatment during bonding or incorporated into bonding resins to greatly improve the durability of resin-dentin bonds. Alternative approaches such as the use of fluoride-containing resins will be evaluated in an attempt prevent matrix demineralization that we believe is responsible for the exposure of MMPs from the underlying mineralized matrix. This comprehensive approach to improving the durability of resin-dentin bonds should ultimately save billions of dollars in health care and much human suffering.

产品说明：树脂-牙本质粘结的耐久性的缺乏导致巨大的医疗保健成本，因为由于树脂复合物与牙本质的界面耦合恶化，牙齿着色的牙本质需要频繁更换。我们的总体假设是，耐久性的缺乏涉及混合层的树脂和胶原蛋白相的降解，从而产生界面耦合。由于采用了湿粘合技术，粘合剂配方比过去更具亲水性。粘合剂中的亲水性树脂促进不均匀的吸水，从而产生充满水的空隙和通道，加速聚合物中酯键的水解。我们建议通过测量树脂电阻抗的变化来非破坏性地跟踪这些过程的速率。体外和体内的长期粘合研究表明，混合层中的胶原蛋白损失。牙本质基质中的胶原原纤维似乎在体外被水解，即使在没有细菌的情况下，被基质金属蛋白酶（MMPs）在其形成期间被困在基质中，并且缓慢地攻击渗透有树脂的脱矿胶原原纤维。这一总体假设将通过旨在对比亲水性树脂与疏水性树脂的稳定性的实验进行测试;我们还将测试胶原基质完全脱矿时与与脱矿基质结合时的稳定性，脱矿基质在矿化牙本质的10 um范围内，可以缓慢暴露更多MMP，或者当牙本质中的MMP被热或酶抑制剂灭活时。将对多种MMP抑制剂进行测试，以确定它们是否可以防止导致低粘合强度和偶联失效的基质机械性能损失。希望MMP的非特异性抑制剂（例如氯己定或双膦酸盐）可以作为粘接过程中的预处理或掺入粘接树脂中，以大大提高树脂-牙本质粘接的耐久性。将评价替代方法，如使用含氟树脂，以防止基质脱矿，我们认为这是基质金属蛋白酶从底层矿化基质中暴露的原因。这种提高树脂-牙本质粘结耐久性的综合方法最终将节省数十亿美元的医疗保健费用和许多人类痛苦。