Tertiary methacrylamides and thiourethane additives as novel dental composites

作为新型牙科复合材料的叔甲基丙烯酰胺和硫氨酯添加剂

• 批准号: 8610113
• 负责人: Jack L. Ferracane
• 金额: $ 52.02万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8610113
• 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; Drug Formulations; Environment; Enzymes; Esthetics; Failure; Fatigue; Filler; 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; Simulate; 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; silane; simulation; tool; tooth surface

Abstract 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 delivered 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, allowin 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.

摘要