Efeitos da radiação ionizante na composição química e propriedades mecânicas da dentina de ratos diabéticos

Abstract

Objective: Evaluate the effect of irradiation used for radiotherapy in the chemical and mechanical properties of the dentin of diabetic rats. Incisors from non-diabetic (ND) and diabetic (D) rats were sectioned transversally and divided into 2 groups according to irradiation therapy: non-irradiated (NI) and irradiated (I) (n=5). Fourier Transform Infrared Spectroscopy (FTIR) evaluated the protein/mineral, carbonate/phosphate ratios; amide I/amide III and amide I/CH2 ratios, while atomic composition analysis was performed by X-ray Energy-Dispersive Spectroscopy (EDS); and the Knoop hardness (KHN) values was measured of the dentin. All data were analyzed for by using a two-way ANOVA and Tukey’s test (α = 0.05). Based on FTIR, a significant increase in the carbonate/phosphate ratio following irradiation was observed. For amide I/phosphate and amide I/amide III ratios no significant difference was found among groups. However, amide I/CH2 showed decreased ratio for diabetic groups compared with non-diabetic groups. The Ca and P content of the diabetic groups were lower compared with non-diabetic. No significant differences was found between Ca/P ratios. ND groups showed significantly higher KH values, regardless of irradiation. After radiation, the KHN demonstrated significantly decreasing values. It was verified that diabetes and the ionizing radiation altered the chemical composition of dentin by altering the mineral and the organic matrix of rat´s dentin, reducing the microhardness.