The Role of Biofilm on Margin Stability and the Development of Secondary Caries

生物膜对边缘稳定性和继发龋发展的作用

• 批准号: 8141308
• 负责人: Shelton Ray Taylor
• 金额: $ 37万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-10 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8141308
• 关键词: Acrylates; Adolescent; Adult; Affect; Artificial Saliva; Biocompatible Materials; Biomaterials Research; Chemicals; Chemistry; Child; Chronic Disease; Clinic; Clinical Research; Clinical Trials; Composite Dental Resin; Composite Resins; Dental; Dental Research; Dental Restoration Failure; Dental caries; Dentistry; Development; Dimensions; Environment; Esters; Fatigue; Frequencies; Frozen Sections; Human; Hydrolysis; In Vitro; Individual; Interferometry; Investigation; Ions; Kinetics; Laboratories; Lead; Lesion; Life; Measurement; Measures; Mechanics; Methods; Microbial Biofilms; Microelectrodes; Modeling; Monitor; Plant Resins; Polymers; Property; Research; Resolution; Role; Saliva; Scanning; Services; Severities; Shapes; Spectroscopy, Fourier Transform Infrared; Structure; Surface; System; Techniques; Testing; Time; Tooth structure; United States; Vertebral column; base; in vivo; microbial; microleakage; multidisciplinary; oral bacteria; polymerization; programs; public health relevance; research study; restoration; sensor; submicron; theories; time use; tool

DESCRIPTION (provided by applicant): More than 70% of carious lesions (now over 125 million per year) are restored with acrylate-based resin composites which have a median service-life of less than 6 years (vs. 15 years for amalgam). The major reason for replacing these restorations is because of secondary caries, but the reason these lesion develop more rapidly on resin-based composites is unclear. Previous clinical studies on the relationship of the margin gap to the development of secondary caries have resulted in equivocal results due to the complexity of interacting variable and the inability to accurately monitor gap dimensions. More controlled in vitro experiments have focused on amalgams and not resin-based composites. This research will investigate a commercial acrylate-based resin dental composite and relevant polymer systems with the following specific aims: (1) to determine the role of the microgap in the development of secondary caries in human teeth, (2) to define how gap dimension controls the occluded chemistry within the gap, and (3) to determine how the occluded chemistry impacts the structure and properties of the resin and composite. This will be accomplished in a 4 year research effort with a multidisciplinary team and newly available measurement tools and techniques. Restorations with naturally formed microgaps and model restorations with precisely controlled microgap dimensions will be exposed to a realistic, controlled in vitro environment consisting of a consortium of oral bacteria relevant to caries in artificial saliva. The effects of the microbial biofilm on the tooth and the composite surface near the cavosurface margin and on the microgap dimensions will be monitored non-destructively with submicron resolution with a new interferometric technique, Super Resolution Vertical Scanning Interferometry. The relationship of gap dimensions, the activity of the different bacterial strains, and frequency and severity of secondary caries will be determined. In addition, the pH and Ca2+ concentration within the microgap will be measured as a function of depth and time with micro-sensor techniques that are new to dental research. Finally, the direct effect of the occluded microgap chemistry on the resin composite properties and chemistry will be examined using dynamic mechanical testing, fatigue measurements, and a newly developed minibeam technique, as well as FTIR to determine if there is direct evidence of backbone scission by hydrolysis. The successful completion of this research will conclusively test a leading theory for secondary caries in resin-based composites, critically examine the efficacy of these materials for use in dentistry, and develop new, more precise tools for biomaterial investigations in the laboratory and the clinic. PUBLIC HEALTH RELEVANCE: Resin-based dental composites are the principle material used to restore over 120 million cavities each year in the US, but have a very limited service-life that is 40% of an amalgam. This program will use newly available tools and experimental methods to critically evaluate the efficacy of these materials for use in dentistry. New, more precise methods will be developed for biomaterial investigations in the laboratory and the clinic.

描述(申请人提供)：超过70%的龋损(现在每年超过1.25亿)是使用以丙烯酸酯为基础的树脂复合材料修复的，这些树脂复合材料的中位使用寿命不到6年(而银汞合金为15年)。更换这些修复体的主要原因是继发性龋齿，但这些病变在树脂基复合材料上发展更快的原因尚不清楚。以往关于边缘间隙与继发性龋病发展关系的临床研究，由于相互作用变量的复杂性和无法准确监测间隙尺寸，导致了不确定的结果。更多受控的体外实验侧重于汞齐而不是树脂基复合材料。本研究将研究一种商用的丙烯酸酯树脂牙科复合材料和相关的聚合物体系，其具体目的如下：(1)确定微间隙在人类牙齿继发性龋齿形成中的作用；(2)确定间隙的尺寸如何控制间隙内的闭塞化学成分；以及(3)确定闭塞化学成分如何影响树脂和复合材料的结构和性能。这将在一个多学科团队和新可用的测量工具和技术的4年研究工作中完成。具有自然形成的微间隙的修复体和具有精确控制的微间隙尺寸的模型修复体将暴露在现实的、可控的体外环境中，该环境由与人工唾液中的龋齿相关的口腔细菌组成。利用一种新的干涉技术--超分辨垂直扫描干涉技术，将以亚微米分辨率非破坏性地监测微生物生物膜对牙齿和靠近空洞表面边缘的复合表面的影响以及对微间隙尺寸的影响。将确定间隙尺寸、不同细菌菌株的活性以及继发性龋病的频率和严重程度之间的关系。此外，微间隙内的pH值和钙离子浓度将被测量为深度和时间的函数，这对于牙科研究来说是新的微传感器技术。最后，将使用动态力学测试、疲劳测量和新开发的微梁技术以及FTIR来检查闭塞微间隙化学对树脂复合材料性能和化学的直接影响，以确定是否有直接证据表明主干因水解而断裂。这项研究的成功完成将最终检验树脂基复合材料中继发性龋齿的领先理论，批判性地检验这些材料在牙科领域的有效性，并为实验室和临床的生物材料研究开发新的、更精确的工具。 与公众健康相关：树脂基牙科复合材料是美国每年修复超过1.2亿颗龋齿的主要材料，但其使用寿命非常有限，仅为银汞合金的40%。这个项目将使用新的可用的工具和实验方法来批判性地评估这些材料在牙科中的使用效果。将开发新的、更精确的方法，用于实验室和临床的生物材料研究。