New composite material design based on studies of tooth-composite and microbial i

描述（由申请人提供）：拟议的研究将建立模型，用于测试不同的策略和材料，以减少粘合界面的降解，目的是合成具有增强细菌入侵抗性的材料，并最终增加修复的寿命。目的：研究体外模拟人口腔系统树脂-牙界面缘降解及临床修复方法。这项工作将寻求从修复牙齿到细菌迁移到受损界面的降解产物水平的关联。方法：用模拟人唾液酯酶（SHSE）孵育树脂-牙本质黏合标本180天。降解后的标本将单独暴露于变形链球菌UA159或与干酪乳杆菌ATCC 746中，在基于化学调节器的生物膜发酵罐（CBBF）中，模拟口腔条件7天。然后使用活/死背光细菌活力试剂盒对标本进行染色。使用共聚焦激光扫描显微镜（CLSM）单独评估染色标本的边缘界面形态，细菌渗透和生存能力。目的：建立可重复测定变形链球菌和干酪乳杆菌在树脂复合材料上沿树脂-牙本质界面间隙形成生物膜后原位基因表达的方法，并与不渗透表面和浮游细胞进行比较。方法：全基因组转录组分析（DNA微阵列）和个体基因转录分析（定量RT-PCR）将用于鉴定被材料降解产物激活的基因。采用荧光原位杂交（FISH）技术，利用预先定义界面边缘间隙的树脂-牙本质样品，在体外和原位观察与生理相关的空间细菌基因表达。目的：测定细菌对树脂复合材料和胶粘剂的水解降解。方法：将粘合剂和复合树脂（商用或实验性抗菌材料，见下文）材料在缓冲液、SHSE、变形链球菌UA159 +培养基或单独培养基中孵育。通过降解产物的释放来测量材料的生物稳定性，将通过高效液相色谱（HPLC）结合紫外光谱和质谱法来评估。目的：研制新型抗菌树脂，以减少修复体表面和树脂-牙本质边缘界面的细菌负荷和侵入。方法：采用共价偶联药物（甲硝唑或克拉维酸与氨苄西林）合成抗菌树脂。新型抗微生物药物对基因表达和细菌微渗漏的影响将采用上述方法进行评估。这种材料设计方法对牙科保健界来说是新颖的，并且有可能改变复合树脂材料和粘合剂的配方、测试和应用方式。

DESCRIPTION (provided by applicant): The proposed research will establish models for testing different strategies and materials to reduce degradation of the bonded interfaces, with the intent of synthesizing materials with increased resistant to bacterial invasion and ultimately increasing the restoration's longevity. Objective: To study the degradation of resin-tooth interfacial margins with an in vitro simulated human oral system and teeth restored using clinical practice methods. This work will seek to correlate degradation product levels from restored teeth to bacterial migration into compromised interfaces. Methods: Bonded resin-dentin specimens will be incubated with simulated human saliva esterase (SHSE) for up to 180-days. Post degradation specimens will be exposed to S. mutans UA159 alone or with Lactobacillus casei ATCC 746 in a chemostat based biofilms fermentor (CBBF), mimicking oral conditions for 7 days. The specimens will then be stained using Live/Dead Baclight Bacterial Viability Kit. Stained specimens will be assessed individually for marginal interface morphology, and bacterial penetration and viability using confocal laser scanning microscopy (CLSM). Objective: To establish methods for reproducibly measuring gene expression of Streptococcus mutans and Lactobacillus casei in situ after formation of biofilms on resin composite, along the resin-dentin interfacial gap, and compared with impermeable surfaces and planktonic cells. Methods: Genome-wide transciptome analyses (DNA microarrays) and individual gene transcript analyses (Quantitative RT-PCR) will be used to identify gens activated by material degradation products. Using Fluorescent in situ hybridizaton (FISH) physiologically relevant in vitro and in situ spatial bacterial gene expression will be observed within the resin- dentin interface using resin-dentin specimens with pre-define interfacial marginal gap. Objective: To measure hydrolytic mediated degradation of resin-composites and adhesives by bacteria. Methods: Adhesive and composite-resin (either commercial or experimental anti-microbial, see below) materials will be incubated in buffer, SHSE, S. mutans UA159 +media or media alone. The biostability of the materials, as measured by the release of degradation products, will be assessed by high performance liquid chromatography (HPLC) combined with UV spectroscopy and mass spectrometry. Objective: To develop new antibacterial resins to reduce bacterial load and ingress over the restoration's surface and along the resin-dentin marginal interface. Methods: Anti-microbial resin will be synthesized using covalently coupled drugs (metronidazole, or Clavulanic acid and ampicillin). The effect of novel anti-microbials on gene expression and bacterial microleakage will be assessed using the methods described above. This approach to material design is novel to the dental health care community and has the potential to change the way composite resin materials and adhesives are formulated, tested and applied. PUBLIC HEALTH RELEVANCE: Establishing model systems to assess physiologically relevant interactions occurring during salivary and bacterial degradation of dental materials is required to develop the design and application of new composite resin formulations and to provide accurate safety information to health care practitioners and patients. The proposed research will establish models for testing different strategies and materials to reduce degradation of the bonded interfaces, with the intent of synthesizing materials with increased resistance to bacterial invasion and ultimately increasing the restoration's longevity. This approach to material design is novel to the dental health care community and has the potential to change the way composite resin materials and adhesives are formulated, tested, and applied