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: 8990685
• 负责人: HEIDI B KAPLAN
• 金额: $ 35.08万
• 依托单位: UNIVERSITY OF HOUSTON
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-12-24 至 2016-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8990685
• 关键词: Role; Biofilm; Margin; Stability; Development

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（由申请人提供）：超过70％的症状病变（现在每年超过1.25亿）是用基于丙烯酸酯的树脂复合材料恢复的，这些树脂复合材料的中位服务寿命不到6年（amalgam的15年）。取代这些修复体的主要原因是由于次要龋齿，但是这些病变在基于树脂的复合材料上更快发展的原因尚不清楚。先前关于边缘差距与次要龋齿发展的关系的临床研究导致了模棱两可的结果，这是由于相互作用变量的复杂性以及无法准确监控间隙维度的能力。更受控的体外实验集中在汞合金上，而不是基于树脂的复合材料上。 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.这将在四年的研究工作中与多学科团队以及新可用的测量工具和技术一起完成。具有自然形成的微型胶囊和模型修复体具有精确控制的微型尺寸的修复体，将暴露于由与人造唾液中龋齿有关的口腔细菌财团组成的现实，受控的体外环境。微生物生物膜对Cavosurface边缘附近的牙齿和复合表面的影响以及微型尺寸将通过新的干涉技术，超级分辨率垂直扫描量表来无限制地监测。差距维度，不同细菌菌株的活性以及次要龋齿的频率和严重程度的关系。另外，微型AP中的pH和Ca2+浓度将根据深度和时间的函数来测量，这些微传感器技术是牙科研究的新功能。最后，将使用动态机械测试，疲劳测量和新开发的Minibeam技术以及FTIR来确定是否直接证明了通过水解的直接证据，将检查封闭的微型AP化学对树脂复合性能和化学性质的直接影响。这项研究的成功完成将最终检验基于树脂的复合材料中的次要龋齿的主要理论，批判性地检查了这些材料在牙科中的疗效，并开发了用于实验室和诊所的生物材料研究的新的，更精确的工具。 公共卫生相关性：基于树脂的牙科复合材料是美国每年恢复超过1.2亿个空腔的主要材料，但服务寿命非常有限，占合并的40％。该程序将使用新的可用工具和实验方法来批判性地评估这些材料在牙科中使用的功效。将开发新的，更精确的方法用于实验室和诊所的生物材料研究。