DAISA DE LIMA PEREIRA

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Effect of Nd:YAG laser on caries prevention of dental enamel by optical attenuation coefficient with optical coherence tomography (OCT)
2018 - MORAES, MARCIA C.D.; PEREIRA, DAISA L.; ZAMATARO, CLAUDIA B.; ZEZELL, DENISE M.; FREITAS, ANDERSON Z.
Caries is a multifactorial disease, caused by the continuing loss of hydroxyapatite crystals. The association of topical acidulated phosphate fluoride application (APF) and high intensity lasers has the potencial to increase the resistance to demineralization of dental tissues. The Nd:YAG laser, specially associated to a photoabsorber over the dental surface, may induce thermal changes in order to increase the resistance to demineralization. Optical Coherence Tomography (OCT) is a non-ionizing radiation imaging technique that can be performed in real time in vivo and can detect early changes in the optical properties of t issues. This study aimed to characterize the effectiveness of the association of Nd:YAG la ser and APF gel in the prevention of caries lesions in human dental enamel in vitro, due to structural changes in function of the pH cycling, the treatments performed as well as to evaluate the potential of OCT to diagnose early demineralization. 160 human enamel samples were divided in four groups and submitted to pH cycling during 20 days, after the following treatments: G1- untreated; G2- treated with APF gel (1.23% F-, 4min); G3- irradiated with Nd:YAG (1064nm, 84.9J/ cm2, 10Hz) followed by APF application and G4- APF application before Nd:YAG laser irradiation (same conditions of G3). OCT (930 nm) analysis were performed before and after the treatments, 5th, 10th, 15th and 20th day of pH cycling. The optical attenuation coefficient decreased significantly (p<0.05) as demineralization increased over time and better results were achieved in group G4. OCT technique can diagnose early demineralization in enamel.
Assessment of the preventive effects of Nd:YAG laser associated with fluoride on enamel caries using optical coherence tomography and FTIR spectroscopy
2021 - 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.
Uso da tomografia por coerência óptica no monitoramento de lesões de erosão e abrasão em dentina
2016 - PEREIRA, D.L.; FREITAS, A.Z.; ZEZELL, D.M.; ANA, P.A.
O objetivo deste trabalho foi avaliar o potencial da tomografia por coerência óptica (OCT) para o diagnóstico precoce e monitoramento de lesões de erosão e abrasão em dentina. Para isso, foi realizado um estudo in vitro com 192 blocos de dentina radicular bovina de 8 mm2, distribuídos aleatoriamente em quatro grupos experimentais (n = 48): G1- sem tratamento; G2- tratamento com flúor fosfato acidulado (FFA, 1,23% F-, pH = 3,3–3,9); G3- irradiação com laser de Nd:YAG (1064nm, 0,6W, 10Hz, 84,9J/cm2); G4- aplicação de FFA, seguida de irradiação com laser de Nd:YAG. Após os tratamentos, as amostras foram submetidas a um desafio de erosão e abrasão por escovação (Sprite Zero, pH=2,6, 90s, 4x/dia) e remineralização (saliva artificial, pH=7) durante 15 dias, sendo avaliadas por OCT em 5 momentos distintos: antes e após os tratamentos, e após 5, 10 e 15 dias de desafio. Foi possível observar o desenvolvimento e evolução das lesões de erosão/abrasão e também foi possível relacionar a desmineralização do tecido decorrente do processo de erosão/abrasão com o coeficiente de atenuação óptica.
Optical attenuation coefficients obtained through OCT correlates to microhardness in dental human enamel irradiated with Nd: YAG and submitted to demineralization in vitro
2019 - MORAES, MARCIA C.D.; PEREIRA, DAISA L.; ANA, PATRICIA A. da; FREITAS, ANDERSON Z. de; ZEZELL, DENISE M.
This work aims was to correlate the changes in the optical attenuation coefficients obtained through the OCT technique with the values obtained in Knoop sectional microhardness tests over time in dental human enamel samples irradiated with the Nd: YAG laser and Acid Phosphate Fluoride (APF), aiming the prevention of caries lesions in vitro. After Ethical Committee approval, 160 enamel samples, obtained from 40 human tooth molars, were divided into 4 groups: Control group (where no treatment was performed); Fluoride group (APF - fluoride phosphate acidulated for 4 minutes); Fluoride-Laser group: APF followed by irradiation with Nd:YAG laser (DE = 84.9 J/cm2, contact mode, with the use of carbon paste as photoabsorver); Laser-fluoride group (irradiation with Nd:YAG laser followed by APF). The samples of all groups were subjected to pH cycling during 20 days. On days 5, 10, 15 and 20, 10 samples from each group were removed from the cycling for the Knoop sectional microhardness test. Two samples of each group, at each time, were randomly selected for the analysis with FTIR-ATR (Fourier transform infrared spectroscopy associated with attenuated total reflection technique). The analysis by ATR-FTIR showed changes in the chemical composition of the samples of the irradiated groups in relation to Control and Fluoride group. There was correlation between the values of sectional microhardness tests and the measured optical attenuation coefficient by OCT in irradiated dental enamel, showing that the association between fluoride application and Nd:YAG laser irradiation is an important tool for the prevention of tooth enamel demineralization.
Variation on molecular structure, crystallinity, and optical properties of dentin due to Nd:YAG laser and fluoride aimed at tooth erosion prevention
2018 - PEREIRA, DAISA L.; FREITAS, ANDERSON Z.; BACHMANN, LUCIANO; BENETTI, CAROLINA; ZEZELL, DENISE M.; ANA, PATRICIA A.
This in vitro study evaluated the compositional, crystalline, and morphological effects promoted by Nd:YAG laser on root dentin, and verified the effects of laser and topical acidulated phosphate fluoride application (APF-gel) on dentin erosion. 180 bovine dentin slabs were randomized into 4 groups (n = 45): G1–untreated, G2–APF-gel (1.23% F−, 4 min), G3–Nd:YAG (1064 nm, 84.9 J/cm2, 10 Hz), and G4–APF-gel application followed by Nd:YAG laser irradiation. The compositional, crystalline, and morphological effects promoted by treatments were investigated on five samples of each experimental group. The other samples were submitted to a 5-day, 10-day, or 15-day erosive and abrasive demineralization and remineralization cycling in order to create erosion lesions. The area and depth of lesions, as well as the optical attenuation coefficient, were assessed, and all data were statistically analysed (p < 0.05). Nd:YAG laser promoted the reduction of carbonate, the formation of tetracalcium phosphate, as well as the melting and recrystallization of the dentin surface. Laser significantly decreased the area and depth of erosion lesions and altered the optical attenuation coefficient when compared to untreated and APF-gel groups, but the association of APF-gel and laser did not promote an additional effect. Nd:YAG laser irradiation can be a promissory treatment to prevent dentin erosion and the abrasion process.
The use of Nd:YAG laser as an alternative to prevent dentin wear
2016 - PEREIRA, D.L.; ZAMATARO, C.B.; ZEZELL, D.M.; FREITAS, A.Z.; ANA, P.A.
The aim of this study is to verify the potential of Nd:YAG laser and topical acidulated phosphate fluoride application (APF) on preventing dentin wear using the optical coherence tomography (OCT) on monitoring this process.