Novel dental composites based on methacrylamides and thiourethane oligomers

基于甲基丙烯酰胺和硫氨酯低聚物的新型牙科复合材料

• 批准号: 9109968
• 负责人: Carmem S. Pfeifer
• 金额: $ 12.03万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2021-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9109968
• 关键词: Adhesives; Aldehydes; Bacteria; Behavior; Chemicals; Chemistry; Clinical; Clinical Research; Collagen; Composite Resins; Controlled Study; Conversion disorder; Coupled; Data; Dental; Dental Enamel; Dental caries; Dentin; Dentists; Devices; Disadvantaged; Environment; Enzymes; Esthetics; Failure; Fatigue; Filler; Formulation; Fracture; Future; General Population; Goals; Healthcare; Hybrids; Hydrolysis; In Situ; Isocyanates; Kinetics; Life; Longevity; Mechanical Stress; Mechanics; Methacrylates; Microbial Biofilms; Minerals; Modification; Molecular Weight; Oral; Oral cavity; Outcome; Pathway interactions; Patients; Peptide Hydrolases; Physiological; Plant Resins; Polymers; Property; Protocols documentation; Recurrence; Reducing Agents; Refractive Indices; Resistance; Risk; Rosa; Scheme; Services; Side; Silanes; Solubility; Solvents; Specimen; Spectroscopy, Fourier Transform Infrared; Stress; Structure; Sulfhydryl Compounds; Surface; System; Techniques; Technology; Testing; Time; Tooth structure; Urethane; Variant; Vertebral column; Viscosity; Water; analog; base; composite restoration; cost; crosslink; design; esterase; flexibility; improved; interfacial; light transmission; methacrylamide; monomer; novel; photoactivation; polymeric restoratives; polymerization; polymerization shrinkage; polymerization stress; practical application; public health relevance; restoration; restorative composite; restorative dentistry; restorative material; screening; simulation; tool; tooth surface

 DESCRIPTION (provided by applicant): The increasing demand for esthetic dental restorations, both by patients and dentists, has stimulated the improvement of resin composites. Currently these materials are used in the vast majority of direct, chair-side restorations delivere each year. However, hydrolysis and enzymatic attack, together with polymerization shrinkage, pose a challenge to the bonded interface between the tooth and the restoration, which reduces the life-time and reliability of the restorations. This study proposes to synthesize novel tertiary methacrylamide monomers to be used as the organic matrix of dental composites and adhesives, completely departing from the conventional methacrylate chemistry used by nearly all current materials. This monomer system is ideal for this application because it is resistant to hydrolysis and enzymatic attack, and also can be polymerized in situ on command using the same photoactivation protocols already in place, thus facilitating its acceptance by dentists. In addition, methacrylamide-functionalized thiourethane oligomeric additives will be designed to be incorporated into the resin matrix with the objective of providing more homogeneous networks with enhanced toughness, as well as enhanced depth of cure due to improved refractive index match with the inorganic fillers. Three aims are proposed: 1) Tertiary methacrylamide monomers will be synthesized and screened for stability to enzymatic/hydrolytic challenges, as well as polymerization kinetics and flexure properties. Materials able to reach established targets will be formulated into composites and evaluated for long-term stability in a physiologically relevant environment. Restored specimens will be cycled in chambers containing caries-forming bacteria, simulating conditions of the oral cavity. The tooth/restoration interface, as well as the mechanical properties of the composite itself, will be assessed after fatigue cycling. 2) Thiourethane oligomeric species will be synthesized with methacrylamides tethered to their backbones. Thiol and isocyanate starting materials will allow control of backbone flexibilities. Analog oligomers based on thiol-enes and urethanes will be used as controls, allowing us to probe the mechanism of toughening by thiourethanes. Mechanical properties in flexure, polymerization shrinkage, degree of conversion and reaction kinetics will be used as screening tools to identify the oligomer providing the best compromise between decreased shrinkage and increased conversion/mechanical properties (especially toughness). Due to their inherently higher refractive index, thiourethane oligomers will improve light transmission through the material and increase depth of cure. 3) Methacrylamide adhesive materials will be synthesized with aldehyde functionalities to reinforce dentinal collagen through crosslinking. Bond strength and zymography will be used to characterize the quality of the interface, as well as collagen crosslinking and proteolytic activity. The expected outcome of this project is to substantially reduce the organic matrix degradation and shrinkage, while increasing conversion and mechanical properties, ultimately overcoming the major drawbacks of current direct polymeric restoratives.

 描述(申请人提供)：患者和牙医对美容牙科修复体的需求不断增加，刺激了树脂复合材料的改进。目前，这些材料被用于每年交付的绝大多数直接的椅子边修复。然而，水解液和酶的侵蚀，再加上聚合体的收缩，对牙齿和修复体之间的粘结界面构成了挑战，从而降低了修复体的寿命和可靠性。这项研究建议合成新的三元化合物 将甲基丙烯酰胺单体用作牙科复合材料和粘合剂的有机基质，与几乎所有当前材料使用的传统甲基丙烯酸酯化学完全不同。这种单体体系是这种应用的理想选择，因为它能抵抗 此外，还可以利用已有的相同的光活化方案进行原位聚合，从而促进牙科医生的接受。此外，还将设计将甲基丙烯酰胺功能化的硫代乙烷低聚添加剂加入到树脂基质中，目的是提供更均匀的网络，增强韧性，以及由于与无机填料折射率匹配的改善而提高固化深度。提出了三个目标：1)合成叔甲基丙烯酰胺单体，并筛选其对酶/水解性挑战的稳定性、聚合动力学和弯曲性能。能够达到既定目标的材料将被配制成复合材料，并在与生理相关的环境中评估长期稳定性。修复后的标本将在含有成龋菌的房间里循环，模拟口腔的条件。牙齿/修复体接口， 以及复合材料本身的力学性能，将在疲劳循环后进行评估。2)以甲基丙烯酰胺为骨架，合成硫代低聚物。硫醇和异氰酸酯起始材料将允许控制主干的灵活性。以硫代烯和氨基甲酸酯类低聚物为对照，探讨硫代氨基甲酸酯的增韧机理。弯曲力学性能、聚合收缩、转化率和反应动力学将被用作筛选工具，以确定在降低收缩和提高转化率/机械性能(特别是韧性)之间提供最佳折衷的齐聚物。由于其固有的较高折射率，硫代乙烷低聚物将改善材料的透光性，并增加固化深度。3)合成含醛官能团的甲基丙烯酰胺粘接材料，通过交联增强牙本质胶原。将使用粘合强度和酶谱来表征界面的质量，以及胶原蛋白的交联和蛋白分解活性。该项目的预期结果是大幅减少有机基质的降解和收缩，同时提高转化率和机械性能，最终克服目前直接聚合修复剂的主要缺点。