LUCIANO BACHMANN
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Resumo IPEN-doc 28119 Infrared absorption bands characterization of dentin tissue when irradiated by erbium laser2002 - ZEZELL, D.M.; BACHMANN, L.; DIEBOLDER, R.; HIBST, R.The erbium laser radiation is highly absorbed by water molecules present in hard tissues. Erbium laser irradiation effects can be classified in two different regimens: ablative, which produces material removal or sub-ablative, that produces a controlled heated process in the irradiated and adjacent regions. For the Er:YAG laser the ablative threshold is very low, around 1.5J/cm2. When dentin is irradiated bellow threshold, chemical and physical changes can occur. The objective of this work is to identify the infrared absorption changes at dentin tissue induced by the Er:YAG laser irradiation al 2.94 μm with sub-ablative energy densities. In this work it were used energy densities between 0.365 J/cm2 and 1.94 J/cm2 to irradiate 0.5mm slices of bovine dentin. For the infrared analysis a Fourier Transform Infrared spectrometer was used. The studied region was between 4000 cm-1 and 400cm-1 (2.5μm and 25μm). After the laser irradiation, two main changes were observed in the analyzed spectral region: loss of water and alteration in the structure of organic matrix. These alterations can be identified by intensity decrease of the water band between 3800cm-1 and 2800cm-1 and in those bands between 1400cm-1 and 1100cm-1. Only a partial reversion of the water band pattern was observed after 24 hours of hydration, suggesting that erbium laser produces an irreversible alteration in the structure of the organic matrix when irradiated with energy densities bellow the ablation threshold.Resumo IPEN-doc 14797 Changes in crystalline structure in dental enamel irradiated with Er,Cr:YSGG, Ho:YLF and Nd:YAG lasers2008 - ZEZELL, D.M.; ANA, P.A.; ROSA, K.; CRAIEVICH, A.; BACHMANN, L.Resumo IPEN-doc 14584 Effects of lasers on chemical composition of anamel and dentin2009 - ZEZELL, DENISE; ANA, PATRICIA; ALBERO, FELIPE; BACHMANN, LUCIANOBackground: Laser irradiation is a promising alternative for caries prevention due to the possibility of changing the microstructure of dental hard tissues. However, the chemical changes promoted by infrared lasers interaction with dental hard tissue are still unclear. This study investigated chemical and erystallographic changes on enamel and dentin after irradiation with Nd:YAG and Fr,Cr:YSGG lasers aiming caries prevention, Study: Thirty enamel and dentin slabs were obtained from bovine teeth, and wore randomly distributted into six groups: G1- unlased enamel; G2- unlased dentin; G3- enamel irradiated with Er,Cr:YSGG laser (o =2.78 ym) at 5.6 J/em? (25 mJ/pulse); Gd- dentin irradiated with Er,Cr:YSGG at 2.8 J/em? (12.5 mJ/ pulse); G5- enamel irradiated with Nd:YAG laser (> = 1.064 ym) at 84.9 J/em? (60 mJ/pulze), and G6- dentin irradiated with Nd:YAG at 84.9 J/em? (60 md/pulse). Sample surfaces were analyzed by micro-Fourier transform infrared spectroscopy (11-FTIR) at 4000-650 cm ' range and with 4 em”* resolution. After p-FTIR, samples were also evaluated by X-ray diffraction at a Synchrotron monochromatic X-ray beam (Cu-Ka, wavelength of 0.0954 nm). Results: Irradiation with Er,CAYSGG laser promoted the decrease on carbonate content of enamel. After Nd:YAG irradiation, it was observed a significant decrease (p < 0.05) of all organic content of enamel, Er,Cr:YSGG and Nd:YAG lasers promoted a significant decrease on the contents of amides 1 and carbonate of dentin. Both laser irradiations also promoted the formation of tricalcium and tetracalcium phosphates, and also a significant increase (p < 0.05) on the crystal growth of the apatite of enamel and dentin. Conclusion: In conclusion, high IR intensity laser irradiation changes mainly the organic and carbonate contents of both enamel and dentin, as well promotes an increase in crystallite sizes and the formation of new crystallographic phases. These changes can be correlated with the mechanism of the improved resistance of these tissues to demineralization observed in our previous studies.Resumo IPEN-doc 09219 Efeito da irradiacao de superficies radiculares com laser de Er:YAG e diodo - analise termica e morfologica2002 - THEODORO, L.H.; HAYPEK, P.; BACHMANN, L.; GARCIA, V.G.; ZEZELL, D.M.; SAMPAIO, J.E.C.Resumo IPEN-doc 09197 Analise do comportamento termico do laser de diodo no esmalte, dentina e cemento dental - estudo in vitro2002 - PELINO, J.E.P.; HAYPEK, P.; SOARES, S.C.G.; BACHMANN, L.; ZEZELL, D.M.; EDUARDO, C.P.Resumo IPEN-doc 17465 Mechanisms of high intensity lasers for caries prevention and erosion2011 - ANA, P.A.; BACHMANN, L.; BENETTI, C.; GOULART, V.P.; ZEZELL, D.M.Resumo IPEN-doc 10365 Formação de centros paramagnéticos em esmalte e dentina aquecidos2004 - BACHMANN, L.; ZEZELL, D.M.; OSWALDO, BAFRAAlém de radiações ionizantes outros agentes podem produzir centros paramagnéticos em esmalte e dentina: aquecimento, moagem, radiação solar e ultravioleta. Estes radicais apresentam sinais paramagnéticos com propriedades similares aos sinais dosimétricos e por esta razio podem introduzir erros nos espectros dos tecidos mineralizados irradiados. O objetivo deste trabalho é estudar o comportamento dos centros paramagnéticos formados em esmalte e dentina aquecidos entre 100 °C e 1000 °C. Utilizaram-se amostras de esmalte e dentina bovinos em forma de pé. Os experimentos de ressonância paramagnética eletrônica foram conduzidos num espectrômetro Varian E-4, com cavidade retangular TE-102 e operando na banda X (9 GHz). Os tratamentos térmicos foram conduzidos em fornos em atmosfera de ar, com temperaturas entre 100 °C e 1000 °C com tempo de aquecimento de 30 minutos. As amostras utilizadas não apresentaram sinal antes do aquecimento. O esmalte apresentou sinais paramagnéticos quando aquecido entre 300 °C e 1000 °C e a dentina entre 100 °C e 1000 °C. Os sinais observados na dentina aquecida entre 100 °C e 200 °C são reversíveis após seis meses de estocagem, enquanto que as demais amostras aquecidas acima de 200 °C e as amostras de esmalte não apresentaram variações na amplitude entre as medidas realizadas logo após o aquecimento com a amplitude determinada após seis meses de estocagem. Com a evolução do tratamento térmico ocorre a diminuição do valor de g e da largura dos sinais em ambos os tecidos. No esmalte aquecido estes valores apresentam uma repentina diminuição em torno de 500 ©C: o valor de g decresce de 2,0066 (300-500 °C) para 2,0057 (500-900 °C) e a largura decresce de 0,7 mT para 0,3 mT. Na dentina o valor de g decresce de 2,0074 (225 °C) para 2,0057 (950 °C) e a largura decresce de 1,2 mT (150 °C) para 0,35 mT (950 °C). Apesar da determinação da origem dos radicais paramagnéticos observados ainda não estar bem estabelecida, os processos responsáveis por estes sinais possivelmente são: eliminação da água adsorvida, alteração da estrutura do colágeno, degradação da matriz orgânica, formação de cianato, eliminação de água estrutural e formação de defeitos cristalinos.Resumo IPEN-doc 10360 Lasers in caries diagnosis and prevention2005 - ZEZELL, D.M.; ANA, P.A.; RIBEIRO, A.C.; FREITAS, A.Z.; ROCHA, R.M.; OLIVEIRA, M.E.; BACHMANN, L.Resumo IPEN-doc 10341 Formacao de centros paramagneticos em tecidos dentais apos tratamento termico2002 - BACHMANN, L.; ZEZELL, D.M.; SANTOS, A.B.; BELTRAME FILHO, O.Resumo IPEN-doc 10339 Estudo das alteracoes estruturais dos tecidos dentais quando irradiados com lasers emissores no infravermelho2001 - BACHMANN, L.; ZEZELL, D.M.; CRAIEVICH, A.F.
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