Comparative evaluation of the effect of radiation therapy on surface micro hardness of three restorative materials- An in vitro study

Context: Dental restorations in Patients undergoing radiotherapy for the treatment of Malignancies may undergo changes in their physical properties due to the irradiation. Aims: To investigate the effect of Gamma irradiation applied during cancer radiation therapy on the surface microhardness of Cention N, Zirconomer and 3M Filtek Bulkfil Posterior Packable Composite. Settings and Design: In-vitro study conducted in a Dental school. Method and Material: Twenty specimens of each material were prepared within acrylic moulds and these were divided into six groups with 10 of each restorative material per group. Groups 1, 2, and 3 were not subjected to any intervention whereas Groups 4, 5 and 6 were subjected to the radiotherapy protocol which is used on patients with malignancies. Statistical Analysis Used: Two-way repeated ANOVA and Tukey’s test. Results: After irradiation the comparative changes in the surface microhardness in all the groups were statistically significant. The values of surface hardness of the Filtek group remained the highest followed by the Cention and Zirconomer groups. Conclusions: The conclusion than can be drawn from this study are that the exposure to Gamma radiation does affect the surface hardness of the materials tested.