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Resumo IPEN-doc 25645 Quantitative analysis of capillary non-perfusion in diabetic retinopathy using widefield OCT-angiography2018 - ALIBHAI, A.Y.; PRETTO, LUCAS R. de; MOULT, ERIC; SCHOTTENHAMML, JULIA; OR, CHRIS; ARYA, MALVIKA; MCGOWAN, MITCHELL; BAUMAL, CAROLINE; WITKIN, ANDRE J.; DUKER, JAY S.; FUJIMOTO, JAMES G.; WAHEED, NADIA K.Purpose : Several OCT angiography (OCTA) studies suggest an association between capillary non-perfusion, a surrogate for retinal ischemia, and diabetic retinopathy (DR) severity. However, due to technical limitations, these studies focused on either 3x3mm or 6x6mm fields of view centered on the macula. In contrast, widefield fluorescein angiography (FA) studies suggest that the majority of capillary non-perfusion in early DR occurs outside of the macular region. The recent development of high-speed, widefield OCTA systems, has for the first time allowed non-invasive visualization of retinal vasculature over wider fields of view—a functionality that, in light of previous widefield FA studies, may be promising for early detection and monitoring of DR. This study aims to couple the recent technological advances in high-speed, widefield OCTA with image processing methods to allow for semi-automatic quantitative analysis of capillary non-perfusion of widefield OCTA images of diabetic eyes. Methods : A semi-automatic, texture-based algorithm that detects areas of non-perfusion on 12x12mm SS-OCTA images from the Zeiss PlexElite™ system was developed. We tested the algorithm on a series of patients with diabetes without DR (28 eyes, 21 subjects; 54.8 ± 10.9 y/o), eyes with non-proliferative DR (NPDR) (24 eyes, 16 subjects; 62.1 ± 13.2 y/o) and eyes with proliferative DR (PDR) (21 eyes, 14 subjects; 52.2 ± 12.7 y/o). Results : There was a general trend of increasing capillary non-perfusion with increasing DR severity; however, there was significant overlap between patients having different DR severities (Fig. 1). Conclusions : Quantitative analysis of widefield OCTA images may be useful for early detection and monitoring for diabetic retinopathy progression in diabetics. Additional work is needed to determine the added value of widefield OCTA.Resumo IPEN-doc 22998 Periodontal treatment combined to antimicrobial photodynamic therapy2017 - GODOY-MIRANDA, BIANCA; BELINELLO-SOUZA, ESTEFANI; ALVARENGA, LETICIA; LEAL, CINTIA; LEITE, CAROLINA; LIMA, TAIRINE; PREVIATI-OLIVEIRA, JHOSEPHER; FREITAS, ANDERSON; PRETTO, LUCAS de; FERNANDES, ADJACI; PRATES, RENATOBackground: Antimicrobial photodynamic therapy (APDT) has been used as an adjuvant treatment for periodontitis. It combines a photosensitizer (PS) with a light source to induce reactive oxygen species (ROS) and kill microbial cells. PpNetNI is a protoporphyrin derivate, and it has a chemical binding site at biofilm and great affinity to microbial cells. The aim of this study was to investigate the effects of APDT as an adjuvant treatment for periodontitis. Study: Ten healthy male rats Wistar (Rattus norvegicus) were used in this study (Approved by UNINOVE Ethical committee AN0029/2015). Periodontitis was induced by placing a cotton ligature around the first mandibular molar in a subgingival position. The contralateral mandibular first molar received neither a ligature nor any treatment, and was used as a control. After 7 days, the ligature was removed and all animals received scaling and root planning (SRP) and were divided according to the following treatments: SRP group (received SRP and irrigation with PpNetNI, 10 mM) and PDT group (PpNetNI 10 mM followed by LED irradiation). PDT was performed with a LED (630 nm) with an output power of 400mW (fluence-rate 200mW/cm2; fluence 18 J/cm2). Rats were euthanized at 7 days postoperatively. The bone loss was measured by Optical Coherence Tomography (OCT, THORLABS LTD., Newton, US). Data were analyzed statistically (Mann-Whitney test, p<0.05). in vestibular region of the first molar Results: The animals treated by APDT showed a bone gain of approximately 30% compared to the SRP group following 7 days from the treatment. OCT was able to detect bone loss in the samples and it was nondestructive method for this experimental model. Conclusion: In conclusion, within the parameters used in this study, APDT was an effective alternative to held periodontal health after treatment, and it was able to regenerate supportive periodontal tissue.Resumo IPEN-doc 24482 New method for depth analysis of Y-TZP t-m phase transformation2017 - ARATA, A.; PRETTO, L.R. de; USSUI, V.; LIMA, N.B.; FREITAS, A.Z.; MACHADO, J.P.B.; TANGO, R.N.; SOUZA, G.M. de; LAZAR, D.R.R.Purpose/aim: The aim of this studywas to validate the optical coherence tomography (OCT) as a nondestructive method of analysis to evaluate the depth of tetragonal to monoclinic (t-m) transformed zone and to calculate the kinetics of phase transformation of a monolithic Y-TZP after hydrothermal aging. Specifically, to compare the activation energy of t-m transformation calculated by the depth of the transformed zone using scanning electron microscopy (SEM) and OCT. Materials and methods: Fully sintered (1450 ◦C/2 h) discs of dentalY-TZP (LAVAPLUS, 3M-ESPE)were aged in hydrothermal pressurized reactor to follow the phase transformation kinetics at 120 to 150 ◦C. Four samples per aging time were analyzed by OCT (OCP930SR, Thorlabs Inc.), = 930 nm, spectral bandwidth (FWHM) of 100 nm, nominal resolution of 6 m (lateral and axial) in air, declared digital resolution 3.09 m (axial). Three areas of 3mm (lateral) were observed to calculate the phase transformation depth (Image J). X-ray diffraction analysis (XRD) were performed, Cu-K , 20◦ to 80◦, 2 . The data were refined using the Rietveld method (GSAS). The transversal section of one specimen of each group was submitted to backscattered SEM analysis to calculate the phase transformation depth (Image J). The speed of the transformation zone front was determined plotting the phase transformation depth versus aging time. Results: XRD results indicated that Y-TZP that 66% is the maximum value of monoclinic phase concentration for all aged Y-TZP. The activation energy for the monolithic Y-TZP was 107.53 kJ/mol. One year and 5 years of hydrothermal aging at 37 ◦C will present approximately 4.21% and 15% of monoclinic phase, respectively. The comparison of the depth of the transformed zone using SEM and OCT were similar, showing a linear behavior and providing information that the opaque layer observed by OCT is related to the depth of the transformed zone (Fig. 1), any difference among the results could be a result of the refraction index correction. The energy of activation calculated by SEM and OCT were 114 kJ/mol and 100 kJ/mol, respectively. The speed calculated for the phase transformation into the bulk of the transformed zone estimated for 37 ◦C was 0.04 m/year (SEM) and 0.16 m/year (OCT). Conclusions: The results indicate that activation energy values determined by SEM and OCT observations were similar allowing the use of the OCT as a tool for monolithic Y-TZP t-m phase transformation kinetic evaluation. Moreover, OCT method has the advantage of a shorter analysis time, without the need of sample preparation steps.Resumo IPEN-doc 23549 Y-TZP low temperature degradation: a sigmoidal or a linear behavior?2016 - ARATA, A.; PRETTO, L.R. de; USSUI, V.; LIMA, N.B.; FREITAS, A.Z.; MACHADO, J.P.B.; TANGO, R.N.; SOUZA, G.M.D. de; LAZAR, D.R.R.