Radiotherapy Impact on Structure/Mechanics of Mineralized Tooth Tissue

Investigators: Mary P. Walker and Yong Wang, UMKC-Dentistry (Co-PIs)
The objectives of this project are to characterize radiation-induced structure and property changes at the dentin-enamel junction and the proximal mineralized tissues to understand the mechanism related to the aggressive, destructive breakdown of the dentition that occurs following oral cancer radiotherapy. The DEJ, the natural connector between enamel and subjacent dentin, plays a critical role in maintaining the biomechanical integrity of the tooth. The clinically observed differences between healthy and irradiated teeth suggest that radiation may induce structural changes within the DEJ and the proximal dentin and enamel; these changes may act as flaws, which driven by cyclic occlusal loading, propagate until reaching a critical crack length precipitating enamel fracture from the dentin. Thus, identifying radiation-induced structure and property changes within the DEJ and the proximal mineralized tissues is essential. Complementary techniques, micro-Raman spectroscopy and scanning acoustic microscopy, will be used to assess correlations of structural changes such as mineral content/distribution, mineral/collagen ratio, and collagen order/disorder with micro-mechanical properties at or near the DEJ in teeth as a function of tooth-level therapeutic radiation dose and compared to evaluations of non-irradiated, healthy teeth. This information will be a key consideration for the development of improved preventive and restorative treatments for post-radiation head and neck cancer patients, while the characterization of the healthy DEJ will provide information useful for overall dental restorative treatment.