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ePaper created 2016-04-05, 13:01:42 | version 1.38.0
| research 20 laser 1 2016 of 0.75 to 4.5 Watts with frequencies of 20 to 50 Hertz, an air percentage of 10% and water cooling percentageof50to90witharadiationtimeranged from 20 to 180 seconds. Before radiation on each cavity, the other cavities were covered with alumi- num paper. Radiation was commenced by locating the laser fibre in each cavity. Time was also mea- sured by watch on the basis of different settings. Laser radiation was accompanied with water spray as abolisher. Samples of the control group were also rinsed with tab water using a 10cc syringe af- ter drilling the related cavities. SEM imaging For provision of the SEM images, initially all cavities were cut in half and prepared according to the study conducted by Freitas et al.18 In summary, after cutting the cavities, samples were submersed in 2.5% glutaraldehyde solution in combination with 0.1 molar sodium cacodylate buffer solution with acidity degree of 7.4 for 12 hours and at a temperature of 4°C. Then all samples were dehydrated using 25% to 100% ethanol solu- tion; hexamethyldilslazane solution was used for 10 minutes for drying the samples. Paper filters were used at the time of airbrushing the samples; then samples were mounted in aluminum tubes using a silver-gold colloid adhesive. Cavities were imaged using SEM before and after exposure to ra- diation to evaluate the condition of smear layer qualitatively. Statistical analysis The data were qualified according to presence/ absence of smear layer which were analysed using Mann-Whitney U-Test and SPSS 17 software. Findings The SEM images captured from cavities exposed to 16 settings of Er,Cr:YSGG laser are presented in Figs. 1–6. The images are captured from four set- tings after 100% removal of smear layer.1 Images are demonstrated on the basis of different settings. Series (a) of images are taken prior to application of radiation and series (b) show the results of ap- plication. Among the mentioned 16 settings, only the numbers 13 to 16 (Figs. 1–6) revealed an ap- propriate removal of smear layer. SEM images of settings 13 to 16 and control group are illustrated here. Discussion The main objective of this study is to evaluate the bactericidal effect of various settings of Er,Cr:YSGG laser radiation. According to the findings of the research, from a total of 16 set- tings, 1.5 and 3 Watt radiation condition, fre- quencies of 15 and 30Hz and time of 20 and 40 seconds, a smear layer removal efficiency of up to 100% was achieved in comparison to the control group. Figs. 1–6: SEM images of settings 13 to 16 and control group before intervention. Fig. 1 Fig. 4 Fig. 2 Fig. 5 Fig. 3 Fig. 6 12016