Are controlled localised degradation of resin composites and remineralisation effective in preventing secondary caries?

树脂复合材料的受控局部降解和再矿化是否能有效预防继发龋？

• 批准号: 2776426
• 金额: --
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2776426
• 关键词: controlled; localised; degradation; resin; composites

Project Description: With health aging, the demand of tooth filling materials has shown a steady increase with an estimated compound annual growth rate of 5.6% between 2021 and 2027 and the global market size of tooth filling materials was valued at over USD 1.8 billion in 20201. Dental resin composites are the most commonly used direct restorative materials for children and adults with a reported annual failure rate of 1-4%2. The replacement of failed restorations consumes a significant amount of clinical time and imposes high financial costs for both health care systems and patients.Secondary caries is the main reason for restoration replacement and occurs as a consequence of microcracks developed between the restoration and tooth tissues due to polymerisation shrinkage of resin composites. Localised degradation can accelerate the development of mirocracks. The presence of microcarcks allows cariogenic bacteria in saliva to grow leading to secondary caries at restoration margins. Avoid micocracks and localised degradation would be the most effective ways to inhibit secondary caries, however, due to the nature of the monomer polymerisation and solidification, volume loss associated with the polymerisation shrinkage of light curable dental resin composites and localised degradation arose from the unconverted C=C bond are unavoidable, therefore, microcracks can not be completely avoided. Despite different prevention methods such as the use of fluoride, teeth cleaning, regular check-ups have been suggested, the effectiveness is strongly dependent on individual compliances. There is a clear lack of intrinsic preventative mechanism. This PhD project aims to 1) better understand the mechanism of secondary caries, 2) establish lab model and cell culture model to monitor the development of microcracks and the progression of secondary caries, 3) evaluate the effectiveness of controlled localised degradation and remineralisation of resin composites in preventing secondary caries, and 4) ultimately develop a biologically safe resin composite that is effective in preventing secondary caries for better Oral Health. The successful candidate will have the opportunity to learn how dental resin composites are formulated, and characterise a wide range of clinical relevant properties following ISO 4049-2019 and methods recommended by Academy of Dental Materials to understand the chemical, structural and property relationship of resin composites. The development of microcracks and the progression of secondary caries will be monitored and the biological safety including cytotoxicity and apatite formation will be investigated. A range of the state-of-the-art world-class characterisation facilities within the Henry Royce Institute at the University of Manchester will be used including a nanoscale AFM-IR - to be employed to map the localised degree of conversion, water degradation (heavy water D2O) and apatite formation. The successful candidate will have access to Doctoral Academy Training Programme and opportunities to participate and lead outreach activities. Opportunity to visit global partner Prof. Xiaojing Chen at the Xiangya School of Stomatology, Central South University in China may also be possible.

项目描述：随着健康老龄化，牙齿填充材料的需求稳步增长，预计2021年至2027年复合年增长率为5.6%，到20201年全球牙齿填充材料市场规模将超过18亿美元。牙科树脂复合材料是儿童和成人最常用的直接修复材料，据报道年失败率为1-4%2。更换失败的修复体会消耗大量的临床时间，并且给医疗保健系统和患者带来高昂的财务成本。继发龋是修复体更换的主要原因，是由于树脂复合材料的聚合收缩而在修复体和牙组织之间形成微裂纹的结果。局部降解会加速微裂纹的发展。微龋齿的存在使得唾液中的致龋细菌得以生长，导致修复体边缘处继发龋齿。避免微裂纹和局部降解是抑制继生龋齿最有效的方法，然而，由于单体聚合和固化的性质，光固化牙科树脂复合材料聚合收缩引起的体积损失以及未转化的C=C键引起的局部降解是不可避免的，因此微裂纹不能完全避免。尽管建议采取不同的预防方法，例如使用氟化物、清洁牙齿、定期检查，但其有效性在很大程度上取决于个人的依从性。明显缺乏内在的预防机制。该博士项目旨在1）更好地了解继发龋的机制，2）建立实验室模型和细胞培养模型来监测微裂纹的发展和继发龋的进展，3）评估树脂复合材料的受控局部降解和再矿化在预防继发龋方面的有效性，以及4）最终开发出一种生物安全的树脂复合材料，可有效预防继发龋，改善口腔健康。成功的候选人将有机会学习牙科树脂复合材料的配制方法，并按照 ISO 4049-2019 和牙科材料学院推荐的方法表征各种临床相关特性，以了解树脂复合材料的化学、结构和特性关系。将监测微裂纹的发展和继发龋的进展，并研究生物安全性，包括细胞毒性和磷灰石形成。将使用曼彻斯特大学亨利·莱斯研究所内的一系列最先进的世界级表征设施，包括纳米级 AFM-IR，用于绘制局部转化程度、水降解（重水 D2O）和磷灰石形成。成功的候选人将有机会参加博士学院培训计划，并有机会参与和领导外展活动。也可能有机会拜访中国中南大学湘雅口腔医学院的全球合作伙伴陈晓静教授。