LUCIANO BACHMANN
27 resultados
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Resumo IPEN-doc 09172 Effects of the diode laser irradiation on root surfaces2004 - HAYPEK, P.; THEODORO, L.H.; BACHMANN, L.; EDUARDO, C.P.; SAMPAIO, J.E.C.; ZEZELL, D.M.The purpose of this study was to evaluate the temperature rising inside the pulpar cavity during the diode laser irradiation on the root surface. Twelve single root teeth were used and their mesial and distal surfaces were irradiated (808 nm, 400 m, 30 s), in a continuous mode (CW) and in an switched mode (SW) (10 Hz). The temperature rise was evaluated deppending with the power used (0.4 W to 2.2 W). The temperature was monitorated with a termopar (T) fixed inside de pulpar cavity during the irradiation. In a second step two parameters was used in a SW (10 Hz). The safety temperature was keep using the power: Group A - 0.9 W (mesial ) and Group B - 1.08 W (distal). The results showed the termal pulpar events (T) during the irradiation, based in an specific relation with the power (P), like T= -0.4+3.7P in a CW and T= -0.2+2P in a SW. The temperature rising during the irradiation was 3.4±0.4ºC on Group A and 4.0±1.0ºC on Group B. The irradiation mode and the power are much important to temperature rise inside the pulpar cavity and the 0.9 W and 1.08 W radiation on the root surfaces were safety.Resumo IPEN-doc 08431 Chemical Modification of bovine dental enamel irradiated with holmiun laser2004 - EDUARDO, P.L.P.; BACHMANN, L.; SALVADOR, V.L.; ZEZELL, D.M.This study investigated Ho:YLF (2,065 mm) effects on dental enamel with regards to the thermal variations in the pulp chamber during irradiation and resistance to demineralization. Twenty samples of bovine enamel were divided: 1) control- acidulated phosphate fluoride (APF) topic application followed by demineralization treatment with lactic acid; 2) Ho:YLF irradiation (100J/cm2) followed by APF and demineralization; 3) Ho:YLF irradiation (350J/cm2) followed by APF and demineralization; 4) Ho:YLF irradiation (450J/cm2) followed by APF and demineralization. All samples were quantified according to their calcium and phosphorous atoms relative concentrations before and after the treatments. X-Ray fluorescence spectrochemical analysis showed an increase on the calcium and phosphorous atoms concentration ratio and therefore the enamel demineralization reduction as a result of the lactic acid treatment in the samples irradiated with the holmium laser followed by the APF (ANOVA, Tukey p<0,01). To evaluate the feasibility of this study for clinical purposes, surfaces morphology were analyzed. Modifications were characterized by melted and re-solidified regions of the enamel, which can changes its permeability and solubility. Temperature changes of ten human pre-molars teeth irradiated with 350 J/cm2 and 450 J/cm2 were also monitored in the pulp chamber in real time. Temperature increases were limited to 4,2° C.Resumo IPEN-doc 01531 Changes in chemical composition and collagen structure of dentin tissue after erbium laser irradiation2004 - BACHMANN, L.; DIEBOLDER, R.; HIBST, R.; ZEZELL, D.M.The erbium laser light has a great affinity to the water molecule, which is present in great quantity in biological hard tissues. The objective of this work is to identify chemical changes by infrared spectroscopy of irradiated dentin by an Er:YAG - 2.94μm laser. The irradiation was performed with fluences between 0.365 J/cm2 and 1.94 J/cm2. For the infrared analysis a Fourier transform infrared spectrometer was used. After the irradiation were observed: loss of water, alteration of the structure and composition of the collagen and increase of the OH- radical. These alterations can be identified by a decrease of the water and OH- band between 3800-2800 cm-1, bands ascribed to collagen structure between 1400-1100 cm-1. The results show that the erbium laser changes the structure and composition of the organic matrix, OHradical and the water composition in the irradiated dentin.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.Artigo IPEN-doc 22516 Infrared spectroscopy of dentin irradiated by erbium laser2003 - BACHMANN, LUCIANO; DIEBOLDER, ROLF; HIBST, RAIMUND; ZEZELL, DENISE M.Livro IPEN-doc 11291 Estrutura e composição do esmalte e da dentina: Irradiação laser e tratamento térmico2005 - BACHMANN, LUCIANO; ZEZELL, DENISE M.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 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 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 10341 Formacao de centros paramagneticos em tecidos dentais apos tratamento termico2002 - BACHMANN, L.; ZEZELL, D.M.; SANTOS, A.B.; BELTRAME FILHO, O.
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