FTIR analysis of human dentin submitted to gamma radiation

Abstract

Global data indicate that head and neck cancer express one of the sixth most common types of malignant cancers. In 2030, head and neck cancer predict 1,031,439 new cases per year around the world. Radiation therapy is used as a major therapy step in the treatment protocol for head and neck malignancies. Radiation caries consists in a side effect of xerostomia, ie a considerable reduction in the quantity and quality of saliva in the oral cavity, being defined as a type of cavity that advance severely with fast progression being able to injure the dental pulp. Gamma radiation effects can promote changes associated to modification in the enamel prismatic structure, the reduction in surface microhardness and biochemically alterations in the tooth composition. However, other studies where the human dental enamel using ionizing radiation present no differences found in the integrity of the dental enamel and there was no interference in the surface microhardness. In this study, 20 human dentin samples were evaluated, split randomly into the control group and irradiated group at 25 kGy, in the Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The FTIR shows that no significant changes were found in the Phosphate band representing the inorganic material. On the other hand, the Amide I band -chosen as the representative of the organic matrix composed mainly of collagen- showed a significant difference, suggesting a degradation of the organic content. These findings corroborate with SEM analysis after the gamma irradiation dose at 25 kGy.