PEDRO ARTHUR AUGUSTO DE CASTRO
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Artigo IPEN-doc 28982 Nd:YAG laser on dental enamel in the reduction of artificial caries demineralization2019 - ZEZELL, DENISE M.; SILVA, MATEUS R.; CASTRO, PEDRO A.A.; SILVA, TANIA M.; GONCALVES, SERGIO E.P.Nd:YAG-laser associated to a photoabsorber, in the reduction of artificial caries in enamel was evaluated. Eighty bovine specimens with 6mm diameter and 2mm high were obtained and a half of the surface of each was protected as a control. Microdurometer and FTIR were performed initially and 8 groups (n=10) were obtained according to treatments: G1(- control): no-treatment; G2(+control): fluorophosphate; G3(Nd:YAG 60mJ/pulse, 10Hz, 48J/cm2, non-contact); G4(photoabsorber + Nd:YAG 60mJ); G5(Nd:YAG 80mJ/pulse, 10Hz, 64J/cm2); G6(photoabsorber + Nd:YAG 80mJ); G7(Nd:YAG 100mJ/pulse, 10Hz, 80J/cm2); G8(photoabsorber + Nd:YAG 100mJ). De-remineralization cycle were performed for induction of artificial caries and to interferometer, microdurometer and FTIR. Microhardness data were submitted to 2-way ANOVA and Tukey/Dunnett tests 5%. Statistically differences were obtained in the photoabsorberfactor individually and in the interaction between laser and photoabsorber. There was a lower percentage of microhardness loss in the groups with photoabsorber; G8 presented microhardness similar to G2. FTIR data were submitted to T-test 5%. Compared with G2, higher concentrations of carbonate were found in G4, G6 and G8; phosphate in G8; lower Amide-I concentration at G8 and higher Carbonate/Phosphate ratio at G4 and G6. The interferometry results were submitted to 3-way ANOVA of repeated measures 5%. There were statistically differences in the photoabsorber-factor individually and in the time-factor. Photoabsorber decreased the demineralization; Nd:YAG-laser without photoabsorber were less effective than fluoride; Nd:YAG-laser 100mJ with photoabsorber was as effective as fluoride and; the Nd:YAG-laser, associated or not to the photoabsorber, was no more effective than fluoride in the reduction of artificial decay.Artigo IPEN-doc 28909 Biochemical characterization of saliva of smoking and non-smoking patients by using Fourier-transform infrared spectroscopy2022 - FERREIRA, MARIA C. de M.S.C.; LEAL, LEONARDO B.; NOGUEIRA, MARCELO S.; CASTRO, PEDRO A.A.; PERALTA, FELIPE; ZEZELL, DENISE M.; CARVALHO, LUIS F. das C. e S. deMore than 90% of oral malignant neoplasms consist of squamous cell carcinoma originated from extrinsic and/or intrinsic multifactorial etiology on the epithelium of the oral mucosa. This multifactorial etiology makes early-stage cancer detection challenging due to the lack of associated oral-tissue clinical features and absence of changes on conventional cellular-imaging, serological and histopathological exams. By using a molecular-sensitive optical technique such as Fourier-transform infrared (FT-IR) spectroscopy, disease-specific biochemical changes can be detected non-destructively, non-invasively and with small sample volumes. In this study, we have used FT-IR spectroscopy to analyze saliva samples of control, smoker, and occasional smoker groups and determine their intrinsic molecular changes as well as the performance of sample differentiation by using a neural network classifier. Saliva samples were collected by spitting, homogenized and stored at -20ºC until analysis. Spectral data was collected in the fingerprint region (900cm-1 to 1800cm- 1) by using a Thermo Scientific Nicolet 6700 ATR FT-IR Spectrometer, in which 1-μl samples were placed on the crystal without additives and left to dry completely by an average time of 5 minutes. Data pre-processing and analysis was performed on the OriginPro8.5 and Orange software. Saliva-sample classification was performed with leave-one-out validation. Correctly classified instances were 72.7% for the control group, 65.5% for occasional smokers and 75% for smokers. Sample differences were observed in the peaks at 1076cm-1 (skeletal cis conformation of DNA and symmetric stretching of phosphate [PO2], 1403cm-1 symmetric CH3 modes of protein methyl groups and δsCH3 of collagen, 1451cm- 1 asymmetrical CH3 bending modes of the protein methyl groups, 1547cm-1 of protein band, amide II, peptide and proteins amide II, and 1646cm-1 amide I, C5 methylated cytosine, C==O bond, C==C stretching uracil and NH2 guanine.Artigo IPEN-doc 26768 Infrared Spectroscopy evaluation of burn wound healing2019 - CASTRO, PEDRO A.A. de; ZEZELL, DENISE M.Wound healing is a biological response in order to recover the tissue stability after injury. The impaired healing by thirddegree, when the damage achieves the major part of dermis, is defined in four sequential and overlapping phases: Inflammation, transition, proliferative and maturative1. The role of biochemical cascade associated in each phase are still not fully understood, thus systematic evaluations tests are crucial. In fact, the gold standard to interrogate the molecular signature of wound healing is concern on immunohistochemical analysis. This approach tends to be laborious, timeconsuming and require multiple assays2. Since Fourier transform infrared spectroscopy (FTIR) has been demonstrated in other studies to provide molecular change report upon biological samples, the present study aims to estimate the feasibility of FTIR to discriminate healthy and burned skin throughout wound stages.