THAIS FREITAS RABELO
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Artigo IPEN-doc 28103 Evaluation of the anti-caries effect beyond the critical enamel pH of preventive treatment of fluoride associated with Nd:YAG laser irradiation2021 - JUVINO, AMANDA C.; ROMANO, MARIANA; ALVES, NATHALIA Z.; FREITAS, THAIS R.; ZAMATARO, CLAUDIA B.; ZEZELL, DENISE M.This study aimed to evaluate the anti-caries effect of fluoride associated with Nd:YAG laser irradiation in the h-eatment of enamel Eight groups (n = S) were analyzed: Negative Control pH 4.5; Negative control pH 4; Fluoride pH 4.5; Fluoride pH 4; Nd-YAG pH 4.5; Nd-YAG pH 4; (Fluoride + Nd-YAG) pH 4.5 and (Fluoride + Nd-YAG) pH 4. All samples were analyzed by Scanning Electron Microscopy (SEM) before and after the cycle. Quantification of phosphorus in the cycling solutions was carried out using the colorimetric method, as an indication of enamel demineralization. The anti-caries effect of the Fluoride + Nd: YAG treatment in addition to the critical pH of the enamel can be observed in the morphological analysis, however in the analysis of the demineralization solutions, the amount of phosphorus showed a difference only in the Fluoiide group compared to the others in the investigative pH.Artigo IPEN-doc 26237 Dental enamel submmitted to gamma radiation and ER,CR: YSGG laser associated to fluoride2019 - ZAMATARO, CLAUDIA B.; CARAMEL, AMANDA; RABELO, THAIS F.; KUCHAR, NIELSEN G.; SOGLIA, VICTOR M.L.; ZEZELL, DENISE M.The in situ caries model can use bovine dental samples in human volunteers. Gamma radiation is a very efficient sterilization method that is not expected to alter the mineral content of the hard tissues, avoiding biases in the results. Samples (n=40) were irradiated through a source of 60Co multipurpose irradiator aiming complete sterilization (25 kGy/h) with the purpose of accumulating the native plaque on them at an in situ study. An Er,Cr:YSGG laser was used alone and in combination with the topical applications of: 1 dentifrice (1,100 μg F /g) or 2 APF (12,300 μg F--/g). Morphological and chemical analyses were performed by scanning electron microscopy (SEM), determination of alkali soluble fluoride concentration by specific ion electrode and surface microhardness determination. Then, the 15 volunteers used palatal devices containing previously treated samples and remained using F dentifrice. The effects of Fformation, on the reduction of demineralization were correlated. The biochemical analysis for quantification of alkaline soluble F determined the groups in which the laser was used after the topical application of the two types of fluoride products of different concentrations (dentifrice and APF) to be statistically different (p≤0.05), suggesting a prolonged effect of the synergy of the treatments in the reduction of the demineralization. Electronic Microscopy Scanning analysis has not shown thermal damage neither interprismatics changes from hydroxyapatite crystals, at dental enamel outside the buccal environment, after 25 kGy gamma irradiation, established that gamma radiation could be used aiming dental enamel sterilization.Artigo IPEN-doc 26236 Effect of Er,Cr:YSSG laser on dental Veneers removal submitted to gamma radiation2019 - ZANINI, NATHALIA; RABELO, THAIS F.; ZAMATARO, CLAUDIA B.; JUVINO, AMANDA C.; KUCHAR, NIELSEN G.; CASTRO, PEDRO A.A. de; ANA, PATRICIA A. da; ZEZELL, DENISE M.The search for aesthetical rehabilitive treatment such as porcelain veneers is increasing over the past years. After CEP-FOUSP approval, the present study investigated the debonding of 20 ceramic fragments of lithium disilicate(5x5x1 mm) from human dental enamel bond with Variolink ® N. The samples were splitted in two groups: control (without gamma irradiation) and treatment (gamma irradiation: GL). EDS and FTIR was performed on enamel in both groups, before and after treatment. After cementation of the ceramic fragments the control group was only irradiated with Er, Cr: YSGG laser (λ = 2.78 nm) to remove the fragments, whereas the GL was gamma irradiated with 0.07 kGy followed by laser irradiation Er, Cr: YSGG for removal of laminates.The laser parameters were previously determined as follows: 3.5 W. The gamma and laser (GL) group was exposed to gamma radiation and the erbium laser was applied in both groups to remove lithium disilicate laminates from human dental enamel. Thus, the load required to remove the laminates after simulation of the radiotherapy treatment in the human dental enamel was analyzed by mechanical assay. In this assay, the GL group presented higher loads for the removal of the laminates compared to the control group. This indicates that the gamma radiation induces a water radiolysis by modifying the hybrid layer of the adhesive cement and increases the bond between the enamel and the resin cement, which hinders the laser debonding of the laminates.Artigo IPEN-doc 26235 FTIR analysis of human dentin submitted to gamma radiation2019 - KUCHAR, NIELSEN G.; ZAMATARO, CLAUDIA B.; CASTRO, PEDRO A.A. de; RABELO, THAIS F.; JUVINO, AMANDA C.; ZANINI, NATHALIA; ZEZELL, DENISE M.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.