PEDRO ARTHUR AUGUSTO DE CASTRO
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Artigo IPEN-doc 28066 Assessment of the preventive effects of Nd:YAG laser associated with fluoride on enamel caries using optical coherence tomography and FTIR spectroscopy2021 - DIAS-MORAES, MARCIA C.; CASTRO, PEDRO A.A.; PEREIRA, DAISA L.; ANA, PATRICIA A.; FREITAS, ANDERSON Z.; ZEZELL, DENISE M.Objective This in vitro study characterized and monitored, by Optical Coherence Tomography (OCT) and Fourier Transformed Infrared Spectroscopy (FTIR), the effects of the association of acidulated phosphate fluoride gel (APF-gel) and Nd:YAG (neodymiun:yttrium-aluminum-garnet) laser, as sequencial treatments, in the prevention of incipient enamel caries lesions. Methods 120 human enamel samples were randomized into 3 groups (n = 40): APF-gel (1.23% F-, 4 min.); Laser+APF (Nd:YAG laser irradiation—0.6W, 84.9J/cm2, 10Hz, followed by APF-gel); and APF+Laser (APF-gel followed by laser irradiation). The samples were subjected to a 15-day pH-cycling, evaluated by OCT (quantification of optical attenuation coefficient–OAC) and FTIR (analysis of carbonate and phosphate content) before treatments, after treatments, and on the 5th, 10th and 15th days of pH-cycling. The statistical analysis was performed (α = 5%). Results The Optical Attenuation Coefficient (OAC) assessed by OCT increases with the progression of demineralization, and the Laser+APF presented the highest values of OAC in 10th and 15th days of pH-cycling. Nd:YAG decreased the carbonate content after treatment regardless of the application order of the APF-gel, while APF-gel did not interfere in the composition of enamel. The carbonate content was also changed in the first 5 days of the pH-cycling in all groups. Conclusion Nd:YAG laser irradiation before or after the application of APF-gel did not influence the appearance of incipient caries lesions, showing no synergistic effect. Regardless of the application order of the APF-gel, laser irradiation reduces the carbonate content of the enamel, which also changes during the demineralization process. However, irradiation before the application of APF-gel increased the speed of progression of the lesions, which positively impacts public health as it can prevent caries disease, even in high risk individuals. OCT and FTIR are suitable for assessing this effect.Artigo IPEN-doc 27120 Monitoring the progress and healing status of burn wounds using infrared spectroscopy2020 - CASTRO, PEDRO A.A.; LIMA, CASSIO A.; MORAIS, MYCHEL R.P.T.; ZORN, TELMA M.T.; ZEZELL, DENISE M.Burns are one of the leading causes of morbidity worldwide and the most costly traumatic injuries. A better understanding of the molecular mechanisms in wound healing is required to accelerate tissue recovery and reduce the health economic impact. However, the standard techniques used to evaluate the biological events associated to wound repair are laborious, time-consuming, and/or require multiple assays/staining. Therefore, this study aims to evaluate the feasibility of Fourier transform infrared (FT-IR) spectroscopy to monitor the progress and healing status of burn wounds. Burn injuries were induced on Wistar rats by water vapor exposure and biopsied for further histopathological and spectroscopic evaluation at four time-points (3, 7, 14, and 21 days). Spectral data were preprocessed and compared by principal component analysis. Pairwise comparison of post-burn groups to each other revealed that metabolic activity induced by thermal injury decreases as the healing progresses. Higher amounts of carbohydrates, proteins, lipids, and nucleic acids were evidenced on days 3 and 7 compared to healthy skin and reduced amounts of these molecular structural units on days 14 and 21 postburn. FT-IR spectroscopy was used to determine the healing status of a wound based on the biochemical information retained by spectral signatures in each phase of healing. Our findings demonstrate that FT-IR spectroscopy can monitor the biological events triggered by burn trauma as well as to detect the wound status including full recovery based on the spectral changes associated to the biochemical events in each phase.