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

University Of Maryland Baltimore County, Baltimore MD

Investigators

Abstract

0238237 Arola Dentists 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.