Effect of Bacteria and Mechanical Loading on Degradation of the Composite-Tooth I

细菌和机械载荷对复合齿 I 降解的影响

• 批准号: 8518793
• 负责人: Jack L. Ferracane
• 金额: $ 27.71万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 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/8518793
• 关键词: Anti-Bacterial Agents; Bacteria; Behavior; Biological; Characteristics; Chemicals; Composite Dental Resin; Composite Resins; Cost Savings; Dental; Dental caries; Development; Dimensions; Drug Formulations; Environment; Exposure to; Failure; Fatigue; Fluorides; Fracture; Glass; Goals; Healthcare; Institution; Lead; Life; Light; Longevity; Mechanical Stress; Mechanics; Microbial Biofilms; Nature; Optics; Oral; Oral health; Outcome; Pain; Patients; Plant Resins; Preparation; Process; Property; Recurrence; Resistance; Scanning Electron Microscopy; Services; Simulate; Solutions; Specimen; Stress; Surface; Surface Properties; Testing; Time; Tooth structure; Work; antimicrobial; clinical practice; clinically relevant; composite restoration; demineralization; dental resin; interfacial; multidisciplinary; novel; oral bacteria; oral biofilm; oral pain; public health relevance; research study; response; restoration; restorative composite; restorative dentistry; restorative material

DESCRIPTION (provided by applicant): This application represents a multidisciplinary, multi-institution response to RFA-DE-10-004: Increasing the Service Life of Dental Resin Composites (R01). The primary reasons for replacement of dental composites are caries and fracture. Whereas the mechanisms underlying both are ill-defined, the time course of years preceding most failures suggests that some process of degradation of the material/tooth interface and/or material occurs within the oral environment. Our overall goal is to further elucidate the mechanism of recurrent demineralization of tooth structure by bacteria around dental composite restorations, and to develop solutions for inhibiting it. To do this, we will identify conditions under which bacteria colonize interfaces between dental composite restoratives and tooth structure, by varying the starting size of the interfacial gap as well as the extent of cure of the resin composite. We further intend to evaluate the effect of the exposure to bacteria under cyclic loading on the marginal interface. A central hypothesis to be tested in this study is that there is a finite interfacial gap size that predisposes the composite restorative interface to colonization by bacteria and extensive demineralization, and that this interface may be further degraded by the effects of the bacteria. We also intend to incorporate a novel bioactive glass (BAG) into the resin composite to develop a new dental restorative material. Our hypothesis is that materials with BAG, and the interface between these materials and tooth structure, will undergo less chemical and mechanical degradation than those without an antibacterial bioactive glass when exposed to a combination of fatigue loading and oral-type biofilm formation for extended periods of time. To further probe the mechanism of failure, the anti-microbial behavior of the materials will be varied by producing resins with different extents of cure, which likely reflects the highly variable outcomes produced for dental composites in clinical practice. Materials will be placed into preparations in teeth and biofilms will be grown on their surface before and during intermittent fatigue loading of the interface. Interfacial failure and bacterial presence will be assessed by optical and scanning electron microscopy. Evidence of demineralization will be determined by energy dispersive spectroscopic (EDS) x-ray analysis. Evidence for biofilm effects on composites with and without BAG will be assessed by surface analysis, including gloss, surface roughness and microhardness. This application is particularly responsive to three aspects of the defined scope of the RFA, including development of new materials to confer caries resistance, determining whether the marginal gap size has an effect on bacterial colonization and further demineralization, and elucidating mechanisms of restorative material failure in a clinically relevant environment. The potential beneficial outcome of this work is extensive cost savings in oral health care and reduced oral pain in the US (and globally) due to longer lasting dental resin composite restorations. PUBLIC HEALTH RELEVANCE: The primary reason for replacement of dental composites is further decay of the tooth. Our overall goal is to better understand the mechanism of recurring cavity formation in teeth restored with dental composites when they are exposed to oral bacteria and mechanical stress. Further, we intend to show that new dental composite formulations containing novel bioactive glasses can render the restoration more resistant to the negative effects of bacteria in a simulated oral environment. The outcome of this work may be increased longevity and service life of dental composite restorations, thus saving the patient further pain, money and dental treatment.

描述（由申请人提供）：此申请代表对RFA-DE-10-004的多学科，多机构的响应：提高牙科树脂复合材料的使用寿命（R01）。替换牙齿复合材料的主要原因是龋齿和骨折。尽管两者的基础机制都是错误的，但大多数故障之前的时间过程表明，材料/牙齿界面和/或材料的某种降解过程发生在口腔环境中。我们的总体目标是进一步阐明牙科复合修复体周围细菌对牙齿结构的复发机理，并开发抑制它的溶液。为此，我们将确定细菌在牙科复合恢复和牙齿结构之间定居的条件，通过改变界面间隙的起始大小以及树脂复合材料的治愈程度，从而在牙科复合恢复和牙齿结构之间定居。我们进一步打算评估在循环载荷下对细菌暴露在边际界面上的影响。在这项研究中要检验的一个中心假设是，存在有限的界面间隙大小，使综合修复界面易于细菌和广泛的脱矿化，并且该界面可能会因细菌的作用而进一步降解。我们还打算将一种新型的生物活性玻璃（袋）纳入树脂复合材料中，以开发新的牙科修复材料。我们的假设是，与没有抗菌生物活性玻璃的材料以及这些材料与牙齿结构之间的界面相比，在长时间的疲劳载荷和口服型生物膜形成的结合时，将经历化学和机械降解。为了进一步探测故障的机制，通过产生具有不同疗效的树脂的树脂，材料的抗微生物行为将发生变化，这可能反映了在临床实践中牙科复合材料产生的高度可变结果。材料将被放入牙齿的制剂中，生物膜将在界面间歇性疲劳载荷之前和期间生长在其表面上。界面衰竭和细菌存在将通过光学和扫描电子显微镜评估。脱矿的证据将由能量分散光谱（EDS）X射线分析确定。生物膜对具有和没有袋子的复合材料的证据将通过表面分析评估，包括光泽，表面粗糙度和微硬度。该应用尤其对RFA定义范围的三个方面尤其有反应，包括开发新材料来赋予龋齿耐药性，确定边缘间隙大小是否对细菌定植和进一步的脱矿化有效，以及阐明在临床相关环境中恢复性材料失败的机制。这项工作的潜在有益结果是由于持久的牙齿树脂综合修复体较长，在口腔医疗保健中节省了大量成本，并减轻了美国（以及全球）的口腔疼痛。 公共卫生相关性：替换牙科复合材料的主要原因是牙齿的进一步衰减。我们的总体目标是更好地了解牙齿中牙齿中复发腔形成的机理，当它们暴露于口服细菌和机械应力时，它们会恢复牙齿复合材料。此外，我们打算表明，含有新型生物活性玻璃的新牙科复合制剂可以使恢复在模拟的口服环境中对细菌的负面影响具有更大的抵抗力。这项工作的结果可能是增加牙科复合修复体的寿命和使用寿命，从而节省了患者的进一步疼痛，金钱和牙科治疗。