CAREER: Aging, Tooth Fracture and the Success of Restorative Dentistry

0238237 Arola牙医普遍认为，修复和更换失败的牙齿消耗了他们的大部分临床活动。牙齿断裂是最有害的失败形式，通常需要完全拔除。目前，修复牙齿的断裂是终身口腔健康的主要障碍之一。最近在美国、英国和欧洲报道的研究表明，45岁及以上的成年人中，近50%的牙齿已经修复。因此，尽管年轻人的蛀牙普遍减少，但在未来十年内，牙齿矫正将需要更频繁地进行修复。今天的老年人期望更长，更健康的生活和最希望的功能和美学上可接受的牙列在此期间，建议investigation.The一般假设是，恢复牙骨折是由牙本质的机械性能的变化，随着年龄的增长。牙本质是一种水合的、矿化的硬组织，按体积计占牙齿的大部分。研究活动旨在表征牙本质的力学行为，并利用混合方法将其抗断裂性与年龄相关联。基于初步研究，预期牙本质的断裂韧性随着组织的年龄而降低。为探讨年龄对牙齿折裂的影响，本研究将以三个年龄组的离体第三磨牙为材料，制备牙本质双悬臂梁标本。单调楔形载荷将用于启动和维持稳定的裂纹扩展，而面内位移作为裂纹长度的函数使用云纹干涉法进行监测。来自实验的全场位移将被用作断裂过程的有限元模型的基准解。使用逆分析，可以从数值模型中精确地获得断裂力学及其对能量耗散的贡献。这些活动将通过断裂表面的显微镜分析来补充，以识别和量化老化对牙本质断裂机制的影响。研究活动与一项教育计划相结合，该计划扩大了马里兰州巴尔的摩县大学（UMBC）一项新的中学生外展计划的影响。希望进一步探索他们对科学的兴趣的学生将继续作为研究学者，并在为期6周的暑期课程中在PI的实验室内从事生物医学研究。教育目标是增加马里兰州学校中代表性不足的少数民族在牙科和工程方面的参与，并通过研究学者及其导师对巴尔的摩学校七年级和八年级教室的有组织访问，促进口腔健康和科学。该教育计划得到了UMBC，马里兰州牙科学校和迈耶霍夫学者计划之间的合作伙伴关系的支持。机械工程专业的本科生和研究生以及牙科专业的学生将共同指导研究学者进行调查。Meyerhoff计划将提供专业发展活动，并通过本科生系列研讨会向年轻学者介绍其他部门的生物医学研究。

0238237ArolaDentists generally accept that the revision and replacement of failed restorations consumes the majority of their clinical activities. Tooth fracture is the most detrimental form of failure and often requires complete extraction. The fracture of restored teeth is currently one of the primary obstacles to lifelong oral health. Recent studies reported in the US, UK and Europe indicate that nearly 50% of the teeth in dentate adults aged 45 years and over have been restored. Therefore, in spite of a general decrease in tooth decay among the young, dental restorations will be required and necessitate repair more often over the next ten years. Older people today expect longer, healthier lives and most wish for a functional and aesthetically acceptable dentition over this period.The general hypothesis of the proposed investigation is that restored tooth fractures are fostered by a change in the mechanical properties of dentin with aging. Dentin is a hydrated, mineralized hard tissue that comprises the majority of the tooth by volume. Research activities are aimed at characterizing the mechanical behavior of dentin and correlating its fracture resistance with age utilizing a hybrid approach. Based on preliminary studies, the fracture toughness of dentin is expected to decrease with age of the tissue. To establish the significance of aging on tooth fracture, double cantilever beam specimens will be prepared from the dentin of extracted third molars according to 3 age groups. Monotonic wedge loads will be used to initiate and sustain stable crack growth while the in-plane displacements are monitored as a function of crack length using moire interferometry. Full-field displacements from experiments will be used as the benchmark solution for finite element models of the fracture process. Using an inverse analysis the mechanics of fracture and their contribution to energy dissipation will be obtained precisely from the numerical models. These activities will be complemented with a microscopic analysis of the fracture surfaces to both identify and quantify the influence of aging on the mechanisms of fracture in dentin. The research activities are integrated with an educational plan that extends the impact of a new outreach program for middle school students at the University of Maryland Baltimore County(UMBC). Students who wish to further explore their interests in science will continue as Research Scholars and engage in biomedical research within the PI's laboratory during a 6-week summer program. The educational objectives are to increase participation of underrepresented minorities from Maryland's schools in dentistry and engineering, and promote oral health and science through organized visits from the Research Scholars and their mentors to 7th and 8th grade classrooms in Baltimore's schools. The educational program is supported by a partnership between UMBC, the University of Maryland Dental School and the Meyerhoff Scholars Program. Undergraduate and graduate students in Mechanical Engineering and students from Dentistry will jointly mentor the Research Scholars with their investigations. The Meyerhoff Program will provide professional development activities and introduce the young Scholars to biomedical research in other departments through an undergraduate seminar series.