Institute of Energy and Nuclear Research IPEN/CNEN, Brazil
Title: In vitro study of the composition and microhardness of the hard tissues of the oral cavity submitted to gamma irradiation
Biography: Wilber E B Paredes
Introduction: Clinical Radiotherapy is extremely important for the treatment of malignant lesions of the head and neck region, however, exposure to ionizing radiation can lead to systemic or local complications during and after radiation treatment. Among these immediate local complications, it stands out in the oral cavity xerostomia and the consequent decay of radiation. Regarding late complications produced by radiation, oral mucositis and osteoradionecrosis are included, which are considered dose-dependent lesions, with high incidence in recent decades (1-30%) and unwieldy, although these are presented after completion of treatment and under the influence of local factors. Methodology: The methodology proposed in this study is to analyze the effect of gamma radiation after irradiation of the samples, using the dose rate used in patients suffering with head and neck cancer. The samples were obtained from human enamel and root dentin; and swine mandibular bone, which were previously polished, and then submitted to the analysis of the initial surface microhardness of all groups. Subsequently, the samples were irradiated in a dose rate of 2 Gy per day, completing a total dose of 72 Gy. Finally, the samples were submitted to analysis of surface microhardness after irradiation, and the morphological analysis on the SEM. Results and discussion: The data were analyzed statistically with a significance level of 95% (p <0.05%). Conclusion: From the preliminary results of the surface microhardness of the samples, it was founded a marked loss of hardness in the root dentin, mandibular body and retro-molar region.