Thiourethanes as low-stress modifiers in dental composites

硫代氨基甲酸酯作为牙科复合材料中的低应力改性剂

• 批准号: 8574051
• 负责人: Carmem S. Pfeifer
• 金额: $ 42.96万
• 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 2017-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8574051
• 关键词: Area; Clinical; Clinical Research; Composite Dental Resin; Composite Resins; Contact Lenses; Conversion disorder; Coupling; Dental; Dental caries; Dentists; Development; Drug Formulations; Elements; Ensure; Esters; Esthetics; Failure; Filler; Fracture; General Population; Goals; Healthcare; Hybrids; Hydrogen Bonding; Industry; Isocyanates; Kinetics; Lead; Life; Longevity; Mechanics; Methacrylates; Modification; Nature; Optics; Outcome; Patients; Phase; Plant Resins; Polymers; Polyurethanes; Property; Psychological reinforcement; Reaction; Recurrence; Refractive Indices; Reporting; Residual state; Services; Side; Silanes; Site; Source; Staging; Stress; Structure; Sulfhydryl Compounds; Surface; Techniques; Technology; Testing; Time; Tooth structure; Translating; Urethane; Vertebral column; Water; analog; base; biomaterial compatibility; composite restoration; cost; density; design; flexibility; improved; interfacial; light transmission; monomer; particle; polymeric restoratives; polymerization; polymerization shrinkage; polymerization stress; practical application; public health relevance; restoration; restorative dentistry; restorative material; screening; silane; stem; tool

DESCRIPTION (provided by applicant): The ever increasing demand for esthetic dental restorations, both by patients and dentists, has stimulated the improvement of resin composites and, nowadays, this material responds for the vast majority of direct, chair- side treatments delivered each year. However, the stress that inherently develops from the polymerization of the organic matrix still poses a challenge to the bonded interface between the tooth and the restoration, which reduces the life-time and reliability of such treatments. This study proposes a relatively simple approach that will tackle polymerization stress while increasing conversion and toughness with no changes in the operatory technique. Thiourethane oligomeric additives will be designed to be incorporated into the resin matrix with the objective of delaying the onset of gelation, which will provide extended opportunity for viscous flow, ultimately leading to increased conversion and significantly reduced stress development. The additive will also provide more homogeneous networks, increased toughness and greater refractive index for better match with the inorganic fraction, in turn improving depth of cure. Two aims are proposed: 1) Thiourethane oligomeric species will be synthesized, comprising tethered thiols into their backbones. Thiol and isocyanate starting materials will be judiciously chosen to produce a wide array of backbone flexibilities. Analog oligomers based on thiolenes and urethanes will be used as controls, as well as to probe the mechanism of toughening by thiourethanes. Methacrylate network structure and stress development will be examined as a function of thiourethane flexibility, additive concentration and secondary monomer matrix (including monomers commonly used in dental restorative materials). Mechanical properties in flexure, degree of conversion and reaction kinetics will be used as screening tools to identify the oligomer providing the best compromise between delayed gelation and increased conversion/mechanical properties (especially toughness). In selected cases, polymerization stress will be evaluated concomitantly with conversion, providing a direct demonstration of the extent of polymerization at which the majority of stress (onset of vitrification) starts to develop. 2) Since the organic portion corresponds to only 30-40 % of the total composite volume, the best materials identified under aim 1 will also be tested as filled compositions to ensure that the improvements obtained for unfilled resins hold for composites. This aim will also include the synthesis of a new silane coupling agent containing thiourethane bonds and tethered thiols. This will take advantage of the large surface area of the fillers as toughening and chain-transfer sites to amplify the stress reduction and the gain in mechanical properties. Due to their inherently higher refractive index, thiourethane oligomers will improve the optical clarity of the final composite, increase light transmission through the material and lead to augmented depth of cure. The expected outcome of this project is to substantially reduce polymerization shrinkage stress, while increasing conversion and mechanical properties, ultimately overcoming the major drawbacks of current direct polymeric restoratives.

描述（由申请人提供）：患者和牙医对美观牙齿修复体的需求不断增长，刺激了树脂复合材料的改进，如今，这种材料可以满足每年进行的绝大多数直接椅旁治疗。然而，有机基质聚合产生的固有应力仍然对牙齿和修复体之间的粘合界面构成挑战，从而降低了此类治疗的寿命和可靠性。这项研究提出了一种相对简单的方法，可以在不改变操作技术的情况下解决聚合应力，同时提高转化率和韧性。硫代氨基甲酸酯低聚添加剂将被设计为掺入树脂基质中，目的是延迟凝胶化的开始，这将为粘性流动提供更多机会，最终导致转化率增加并显着减少应力发展。该添加剂还将提供更均匀的网络、更高的韧性和更大的折射率，以更好地与无机部分匹配，从而提高固化深度。提出了两个目标：1）将合成硫代氨基甲酸酯低聚物，其主链中包含束缚的硫醇。硫醇和异氰酸酯起始材料将被明智地选择以产生广泛的主链柔性。基于硫醇烯和氨基甲酸酯的类似低聚物将用作对照，并探讨硫代氨基甲酸酯的增韧机制。甲基丙烯酸酯网络结构和应力发展将作为硫氨酯柔韧性、添加剂浓度和辅助单体基质（包括牙科修复材料中常用的单体）的函数进行检查。弯曲机械性能、转化程度和反应动力学将用作筛选工具来识别低聚物，从而在延迟凝胶化和增加转化/机械性能（尤其是韧性）之间提供最佳折衷。在某些情况下，聚合应力将与转化同时进行评估，直接证明大部分应力（玻璃化开始）开始发展的聚合程度。 2) 由于有机部分仅占复合材料总体积的 30-40%，因此目标 1 下确定的最佳材料也将作为填充组合物进行测试，以确保未填充树脂所获得的改进也适用于复合材料。这一目标还包括合成一种含有硫代氨基甲酸酯键和束缚硫醇的新型硅烷偶联剂。这将利用填料的大表面积作为增韧和链转移位点，以增强应力降低和机械性能的提高。由于其固有的较高折射率，硫氨酯低聚物将提高最终复合材料的光学透明度，增加通过材料的光透射率并导致固化深度增加。该项目的预期成果是大幅降低聚合收缩应力，同时提高转化率和机械性能，最终克服当前直接聚合物修复剂的主要缺点。

项目成果

Thio-urethane oligomers improve the properties of light-cured resin cements.

• DOI: 10.1016/j.dental.2015.02.008
• 发表时间: 2015-05
• 期刊: Dental materials : official publication of the Academy of Dental Materials
• 作者: Bacchi A;Consani RL;Martim GC;Pfeifer CS
• 通讯作者: Pfeifer CS

Polymer-Based Direct Filling Materials.

• DOI: 10.1016/j.cden.2017.06.002
• 发表时间: 2017-10-01
• 期刊: Dental clinics of North America
• 作者: Pfeifer, Carmem S

Impact of thio-urethane additive and filler type on light-transmission and depth of polymerization of dental composites.

• DOI: 10.1016/j.dental.2017.07.020
• 发表时间: 2017-11
• 期刊: Dental materials : official publication of the Academy of Dental Materials
• 作者: Faria-E-Silva AL;Pfeifer CS
• 通讯作者: Pfeifer CS

Shrinkage / stress reduction and mechanical properties improvement in restorative composites formulated with thio-urethane oligomers.

• DOI: 10.1016/j.jmbbm.2017.11.011
• 发表时间: 2018-03
• 期刊: Journal of the mechanical behavior of biomedical materials
• 影响因子: 3.9
• 作者: Bacchi A;Yih JA;Platta J;Knight J;Pfeifer CS
• 通讯作者: Pfeifer CS

Rheological and mechanical properties and interfacial stress development of composite cements modified with thio-urethane oligomers.

• DOI: 10.1016/j.dental.2016.05.003
• 发表时间: 2016-08
• 期刊: DENTAL MATERIALS
• 影响因子: 5
• 作者: Bacchi, Atais;Pfeifer, Carmem S.
• 通讯作者: Pfeifer, Carmem S.