EDUARDO KAZUO KOHARA
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Resumo IPEN-doc 13052 Effects of 960nm diode laser irradiation and fluoride on calcium solubility of dental enamel in vitro2004 - KOHARA, E.K.; KATO, I.T.; WETTER, N.U.The aim of this study is to determine the effects of diode laser (?=960 nm) irradiation on calcium solubility of dental enamel. Sixty enamel specimens were prepared from human teeth and divided into four groups (control, fluoride, laser and fluoride plus laser). Prior to the irradiation a vegetable coal diluted in physiological solution was applied to the enamel surface and the specimens were irradiated using 6,5 W of peak power, 5 ms of pulse duration, 10 Hz of repetition rate, fluency of 3,7 J/cm2 and time exposure of 10 seconds. The acidulated phosphate fluoride was applied for 4 minutes. Next, the specimens were immersed in lactic acid for 24 hours at 37 °C. The calcium content in demineralization solution was evaluated with Inductively Coupled Plasma Atomic Emission Spectrometry. The results indicate an increase in calcium solubility (12%) after laser irradiation, however, not statistically significant. When associated with fluoride, the decrease in calcium solubility did not differ from the results obtained with fluoride only. It can be concluded that in this experiment diode laser irradiation did not increase acid resistance of dental enamel.Resumo IPEN-doc 13050 Microhardness of the dental enamel surface after irradiation with 960nm diode laser2004 - KOHARA, E.K.; WETTER, N.U.; RATTICHIERI, F.; KATO, I.T.Several authors analyzed laser irradiation of dental enamel in an attempt to increase acid resistance and achieve caries prevention. In some cases, the procedure has also been associated to the application of a layer of fluoride. Micro-hardness measurements are reliable tests used to determine the degree of resistance to demineralization. In this work micro-hardness values of superficial dental enamel have been measured before and after irradiation with a 960 nm diode laser, using tested laser parameters that are safe and cause no injuries to the adjacent tissue. Laser parameters were below the dental enamel ablation threshold. 60 enamel samples were used and divided into control group (GC), fluoride application (GF), laser irradiation (GL), fluoride application with subsequent laser irradiation (GFL) and laser with subsequent fluoride application (GLF). A solution containing coal was used on the enamel surface in order to absorb the laser radiation. A statistically significant loss of the micro-hardness value was obtained for all groups except for GL but also this group did not produce significant micro-hardness increase. Conclusion: at the current peak power and beam quality of standard diode laser bars, safe laser parameters do not produce higher micro-hardness values.Resumo IPEN-doc 11228 Effects of low-intensity laser therapy on the Orthodontic movement velocity of human teeth2004 - KOHARA, E.K.; CRUZ, D.R.; WETTER, N.U.; RIBEIRO, M.S.Low-intensity laser therapy (LILT) has been studied in many fields of Dentistry, but, to our knowledge, it is the first time that its effects on orthodontic movement velocity in humans are investigated. In our study, eleven patients were recruited for a two-month study. One half of the upper arcade was considered control group and received mechanical activation of the canine teeth every thirty days. The opposite half received the same mechanical activation and was also irradiated with a diode laser (?=780nm) on ten points around the root, during 10s with 20 mW, 5 J/cm2, on four days of each month. Data of the biometrical progress of both groups were statistically compared. All patients showed significant higher retraction velocity of the canines on the laser treated side when compared to the control. Conclusion: Our findings suggest that LILT does accelerate human teeth movement and could therefore considerably shorten the whole treatment duration.Dissertação IPEN-doc 11245 Estudo dos efeitos da irradiaçao com laser de diodo de 960 nm sobre esmalte de dentes decíduos2005 - KOHARA, EDUARDO K.Artigo IPEN-doc 10883 Effects of low-intensity laser therapy on the orthodontic movement velocity of human teeth: a preliminary study2004 - CRUZ, D.R.; KOHARA, E.K.; RIBEIRO, M.S.; WETTER, N.U.Artigo IPEN-doc 09567 Micromorfologia do esmalte de dentes deciduos apos irradiacao de laser de diodo de alta potencia em funcao do corante iniciador de absorcao2003 - KOHARA, E.K.; MYAKI, S.I.; WETTER, N.U.Artigo IPEN-doc 12917 A new in-vitro method of measuring intra-pulpal temperature2004 - KATO, ILKA T.; WETTER, NIKLAUS U.; KOHARA, EDUARDO K.Artigo IPEN-doc 11846 Effects of 960-nm diode laser irradiation on calcium solubility of dental enamel2006 - KATO, ILKA T.; KOHARA, EDUARDO K.; SARKIS, JORGE E.S.; WETTER, NIKLAUS U.Objective: The aim of this study was to investigate the effects of 960 nm diode laser and acidulated phosphate fluoride on calcium solubility of human dental enamel. Background Data: Interest in diode lasers has grown steadily since its invention due to its inherent advantages and its range of applications. Several other laser types have shown good results in caries prevention; however, there are few studies on dental tissue interactions using diode lasers. Methods: Acid resistance was evaluated using 65 enamel specimens, divided into five groups: control (C), fluoride (F), laser (L), laser + fluoride (LF), and fluoride + laser (FL). The laser was operated using the parameters of 6.5-W peak power, 5-msec pulse duration, 10-Hz repetition rate, and 33-mJ pulse energy. These parameters were previously tested regarding pulpal temperature rise and enamel morphology, and were determined to be safe. The amount of calcium lost during demineralisation was measured. Results: The calcium solubility of the laser group was 12% higher than of the control group (p > 0.05). Group F showed a 33.6% increase of acid resistance (p < 0.05). When laser was associated with fluoride, the calcium solubility increased significantly (p < 0.05) compared to both the control group and the laser group. Groups treated with fluoride showed the same results (p > 0.05). Conclusion: The 960-nm diode laser promoted a slight increase in calcium solubility. A statistically significant reduction on calcium solubility was achieved with the three treatments that involve fluoride (F, FL, and LF). The additional application of laser irradiation did not cause any significant increase or decrease in calcium solubility.