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Resumo IPEN-doc 25611 Effects of gamma irradiation on bovine bone microhardness and molecular structure2018 - DIAS, DERLY A.; PEREIRA, DAISA L.; GOMES, GABRIELA V.; SUGAHARA, VANESSA M.L.; ZAMATARO, CLAUDIA B.; ZEZELL, DENISE M.; MATHOR, MONICA B.The skeletal systems is a complex mixed compounds, organic and inorganic, that should present a mechanical resistance to perform functions as protection of the vital organs and load distribution. Gamma radiation is an ionizing radiation that comes from radioative sources or X-ray generator and it is commonly used in health establishments such as radio diagnostic exams, radiotherapy and sterilization of allograft. The characterization of the irradiated bone tissue can be an important tool in the study of the components that are aÆected and how much each dose of ionizing radiation can alter its mechanical properties. This information will be very important in in vitro and ex vivo studies where sterilization of the bone material is necessary and may still be useful in understanding the eÆects on the bone tissue of patients undergoing short-term radiotherapy. For this, 110 samples of bovine femur diaphysis were randomized into 11 groups: G1- untreated (control); G2 to G11 were submitted to gamma irradiation (60Co Gammacel). Samples were polished before irradiation and submitted to a Knoop Microhardness Test to determine the hardness of bovine bone and Fourier transform Infrared spectroscopy (FTIR). Spectra were collected in the midinfrared range in Attenuated Total Reflectance (ATR) sampling mode associated whit PCA multivariate technique to evaluate the molecular changes in bone matrix. The microhardness analysis did not present a significant statistical diÆerence between the irradiated and control groups, showing that ionizing radiation did not aÆect the mechanical structure of the samples, on a micro scale. The results of FTIR with the PCA technique were eÆective in separating all groups, especially those irradiated with doses of 0.002 kGy, 10 kGy and 35 kGy. We conclude that ATR-FTIR spectroscopy associated with PCA is a good method to evaluate the biochemical changes promoted by ionizing radiation in bone matrix. It was observed that hardness was not altered by gamma irradiation and FTIR spectroscopy associated with PCA is a good method to analyze the changes in bone tissue submitted to ionizing radiation.Resumo IPEN-doc 25609 Molecular characterization of ex-vivo natural bovine dental enamel2018 - ZAMATARO, CLAUDIA B.; PEREIRA, DAISA L.; GOMES, GABRIELA V.; ALVES, NATHALIA Z.; CASTRO, PEDRO A.A.; DIAS, DERLY A.; ZEZELL, DENISE M.; SCAPIN, MARCOS A.Bovine teeth are widely used to infer results on a human population. Considering this, an analysis of the mineral content of bovine enamel, focusing the hidroxiapatite (HA), was carried out to evaluate the homogeneity of the sample universe for future experiments with laser irradiation as a substitute of human teeth enamel. Twelve samples of 5 x 5 mm bovine enamel were prepared and polished plane. The mineral content was calculated through surface microhardness (SMH) and morphology by scanning electron microscopy (SEM). Main molecular components of the enamel were analysed by Energy Dispersive X-ray Spectroscopy (EDS). Surface microhardness is an indirect indicator of the mineral content of the samples, which was 258.2 (38.8) KHN. The compounds present in the samples, the values of Calcium and Phosphate oxides and the ration Ca/P were analizes. As expected Phosphorus pentoxide and Calcium oxide were the main constituent of the samples (57.4 to 59.9%). The CaO/P2O5 ratio shows a variation with linear correlation (R2 = 1). The elemental ratio (Ca/P) shows a change in the elemental content with linear correlation (R2 = 1). 30% of the samples presented Strontium oxide, 30% had Zirconium dioxide, 10% had Magnesium oxide and 40% had Silicon dioxide. All samples showed Sulfur trioxide, Iron trioxide and Chlorine. 10% did not shown Zinc oxide. 5% had Potassium oxide and Nickel oxide in its composition. The surface microhardness results, although only for the initial homogenization of the sample universe, showed a Knoop hardness number within a spectrum similar to that of natural hydroxyapatite of human origin. The EDS results show that bovine enamel hydroxyapatite present great similarity with that from human enamel hydroxyapatite from the point of view of chemical composition. These results corroborate the use of bovine hydroxyapatite in substitution of hydroxyapatite of human origin. Despite the inter-species similarity, it is possible to note that in the same species the composition of hydroxyapatite varies. In the bovine species, the feeding, the period of formation of the dental germs and the origin are more standardized and controlled than in humans. Nevertheless, it is possible to notice a variation of the components elements of bovine dental enamel, and it is necessary to restrict an interval of hardness and Ca/P values to homogenise the samples properties for use in any experiment.Artigo IPEN-doc 24128 Effects of gamma irradiation on microhardness and Fourier Transform infrared spectroscopy of bovine bone2017 - DIAS, DERLY A.; PEREIRA, DAISA L.; GOMES, GABRIELA V.; SUGAHARA, VANESSA M.L.; MATHOR, MONICA B.; ZEZELL, DENISE M.