Abstract 1109: Effects of radiation therapy on the hardness of enamel and dentin

Abstract

Abstract Introduction: Radiation therapy is often used as the main or adjunctive treatment for cancer in the oral cavity. Unfortunately, prolonged exposure to radiation has adverse effects on tissues of the oral cavity, including a decrease in the hardness of dentin. Consequently, patients who receive radiation therapy are susceptible to tooth sensitivity and caries. Fluoride treatments have proven to be effective in restoring the hardness of dentin as it remineralizes the tooth. The aim of this study was to determine the optimal fluoride treatment for restoring the hardness of irradiated teeth. Methods: 100 teeth were extracted, cleaned, and mounted in acrylic resin. The teeth were ground and polished to expose the dentin and enamel. The initial Knoop hardness of the teeth was measured and split equally among five groups and treated as follows: (1) sodium fluoride varnish (SF), (2) MI varnish (MI), (3) silver diamine fluoride and potassium iodide (SDFKI), (4) silver diamine fluoride (SDF), and (5) no treatment (NT). All groups were subjected to 2 grays of daily radiation treatment for 6 weeks. The hardness of the dentin was measured immediately following radiation. Afterwards, the 5 treatments were applied weekly for 6 weeks. Hardness was measured 1 week after each treatment. Kruskal-Wallis one way analysis of variance on ranks was used to compare the different groups. Results: After 6 weeks of fluoride treatment, there was a significant difference (p = 0.013) between the hardness of the irradiated enamel, with Group 4 resulting in the largest median measurement (263.4). Similarly, 5 weeks of fluoride application resulted in a mean hardness of dentin that was 15.8%, 13.6%, 16.2%, and 19.4% higher than the control for groups 1, 2, 3, and 4, respectively. Again, Group 4 had the highest hardness measurement. Conclusions: Radiation therapy decreases the hardness of enamel and dentin. SDF treatment resulted in the highest hardness for both irradiated dentin and enamel, suggesting that SDF is promising as a fluoride treatment for those undergoing radiation therapy for oral cancer. Citation Format: Rachel Kulchar, Florin Eggmann, Celine Mina, Steven Szewczyk, Kakiuchi Yusuke, Jie Deng, Francis Mante. Effects of radiation therapy on the hardness of enamel and dentin [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1109.