Yazar "Çelik E.U." seçeneğine göre listele

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    Bactericidal effect of Er,Cr:YSGG laser on Streptococcus mutans
    (2006) Türkün M.; Türkün L.Ş.; Çelik E.U.; Ateş M.
    The aim of this study was to compare the antibacterial activities of Er,Cr:YSGG laser with two different power outputs against a chlorhexidine gluconate-based cavity disinfectant. A cavity tooth model test was used to determine the antibacterial activity. Four cylindrical cavities were prepared on the dentin surface of 10 bovine incisors and left in contact with Streptococcus mutans for 72 hours to allow bacterial invasion. Following which, Er,Cr:YSGG laser with 0.75 W and 1 W power outputs and a chlorhexidine gluconate-based cavity disinfectant were applied separately on one of the three infected cavities, whereas the fourth was left untreated for control. Standardized amounts of dentin chips were obtained from the cavity walls, and the number of bacteria recovered was counted. Statistical analysis was carried out using one-way ANOVA and Dunnett's C test (p = 0.05). No significant differences were observed among the data obtained from the chlorhexidine gluconate-based cavity disinfectant and the two Er,Cr:YSGG laser groups (p>0.05). However, when compared to the control group, both Er,Cr:YSGG laser groups and the chlorhexidine gluconate-based cavity disinfectant resulted in significantly less bacterial recovery (p<0.05). In conclusion, the antibacterial activity on S. mutans demonstrated by Er.Cr:YSGG laser with both energy outputs was similar to that of the tested chlorhexidine gluconate-based cavity disinfectant.
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    Effect of different laser devices on the composition and microhardness of dentin
    (2008) Çelik E.U.; Ergücü Z.; Türkün L.S.; Türkün M.
    This study determined the compositional changes and microhardness of the cavity floor prepared by Er,Cr:YSGG and Er:YAG lasers and compared the results with the conventional method of bur preparation. Fifteen non-carious human molars were used in this study. On the buccal and lingual surfaces of each tooth, two cavities (mesio-distal 3 mm, inciso-gingival 3 mm, depth 2 mm) were prepared with two different laser devices (Er,Cr:YSGG laser; Waterlase MD and Er:YAG laser; KaVo Key Laser 3) and a high-speed turbine. The teeth were embedded into polyester resin and cross-sectioned. The microhardness measurements from the floor of each half cavity were recorded with the Vickers surface hardness tester. The remaining halves of the cavities were subjected to SEM-EDS atomic analysis. The results were statistically evaluated by one-way ANOVA and Kruskal Wallis tests (p=0.05). No significant differences were observed among the microhardness values, quantities of Ca (Ca weight %), P (P weight %) and Ca/P ratio of the lased and conventionally prepared cavities (p>0.05). The cavity preparation techniques and differences in laser devices did not significantly alter the composition and microhardness of dentin tissue. Both laser devices used in this study were observed to lead to minimal thermal damage in the dentin tissue and minimal thermally-induced changes in dentinal compositions. © Operative Dentistry, 2008.
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    Noncarious class V lesions restored with a polyacid modified resin composite and a nanocomposite: A two-year clinical trial
    (2008) Türkün L.Ş.; Çelik E.U.
    Purpose: The purpose of this study was to compare the clinical performance of a polyacid modified resin composite and a nanocomposite applied with an antibacterial adhesive system over a period of 2 years in noncarious Class V lesions. Materials and Methods: Twenty-four patients with at least two noncarious cervical lesions were enrolled in the study. The teeth were restored with a polyacid modified resin composite (Dyract eXtra, Dentsply DeTrey) or a nanocomposite (Filtek Supreme, 3M/ESPE). Fifty restorations of each material were placed with no marginal bevels and no mechanical retentions using an antibacterial self-etching adhesive system (Clearfil Protect Bond, Kuraray). All lesions were evaluated at baseline, 6, 12, and 24 months periods using the USPHS criteria for color match, marginal discoloration, marginal adaptation, caries formation, anatomic form, postoperative sensitivity, surface roughness, and retention. The changes across the four time points were assessed using Friedman and Wilcoxon Signed Ranks tests. The two restorative materials were compared in the same recall period for each of the criteria using chi-square test (p = 0.05). Results: Dyract eXtra restorations exhibited a significantly better color match than Filtek Supreme restorations; however, all restorations in both groups were clinically acceptable. Filtek Supreme's retention rate (100%) was found to be significantly better than that of Dyract eXtra (96%). Two Dyract eXtra restorations were completely lost while one was partially fractured (p ? 0.05). Significant differences were observed in marginal adaptation and color match of Filtek Supreme restorations and marginal discoloration of Dyract eXtra and Filtek Supreme restorations between the baseline and the 2-year scores (p ? 0.05). Conclusion: Both restorative materials showed acceptable clinical performance in Class V noncarious lesions after 2 years of clinical service.
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    One-year clinical evaluation of the efficacy of a new daytime at-home bleaching technique
    (2010) Türkün M.; Çelik E.U.; Alada A.; GÖkay N.
    The aim of this study was to compare the clinical efficacy and side effects of a new daytime at-home bleaching technique (28% carbamide peroxide [CP] gel) with the overnight application of 10% CP and to determine the change of tooth color 1-year post-treatment. Twenty healthy volunteers were assigned to one of two sample groups of 10. All participants employed one of the two at-home bleaching systems: (1) the new daytime at-home bleaching system including 28% CP gel with a non-custom-fit tray (Meta Tray, Remedent, Deurle, Belgium) for 20 minutes, and (b) the conventional overnight at-home bleaching system with a 10% CP gel and a custom-fit tray (Opalescence PF, Ultradent, South Jordan, UT, USA) for 6 to 8 hours. Digital images and CIE (International Commission on Illumination) L*, a*, and b* spectrophotometric measurements were taken at baseline, after the bleaching treatment and 1-year post-treatment. Tooth and gingival sensitivity was measured with a specially designed 4-point scale. Significant differences were found in L*, a*, and b* values, between initial and post-treatment, for both bleaching systems (p < 0.05). However, no significant difference was detected between post-treatment and 1-year follow-up. The bleaching effectiveness of Opalescence PF was found to be superior to that of Meta Tray, considering the color parameter of ?E (p < 0.05). Meta Tray provoked less tooth sensitivity (p < 0.05), however gingival sensitivity appeared more in this group (p < 0.05). Within the limitations of this study, it can be concluded that the new daytime at-home bleaching system tested (Meta Tray) produced significant bleaching effects. However, the clinical efficacy of the overnight bleaching system was found to be superior to the daytime at-home bleaching system evaluated in this study. The whitening effect remained similar 1-year after the bleaching treatment for both at-home bleaching systems. CLINICAL SIGNIFICANCE Although the new daytime at-home bleaching system tested exhibited significant bleaching effects, overnight bleaching with a 10% CP gel resulted in a higher bleaching effectiveness than this new system. Although the participants using the new bleaching system exhibited less tooth sensitivity probably because of the reduced contact time of bleaching gel with tooth surfaces, the application of the bleaching agent with a non-customized tray provoked more gingival sensitivity in this group. © 2010, Wiley Periodicals, Inc.
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    Oxygen release of tetra acetyl ethylene diamine (TAED) and sodium perborate combination
    (2008) Çelik E.U.; Türkün M.; Yapar A.G.D.
    Aim: To evaluate the effect of tetra acetyl ethylene diamine (TAED) on oxygen release from sodium perborate and to compare it with sodium perborate-hydrogen peroxide (H2O2) and sodium perborate-distilled water mixtures. Methodology: Six groups were evaluated: control groups (groups I-III), sodium perborate was mixed with distilled water or 3% or 30% H2O2; experimental groups (groups IV-VI), sodium perborate was mixed with TAED in different ratios and then distilled water was added to these mixtures. The amount of oxygen released from the samples was measured with a digital oxygen meter at room temperature (25°C) and body temperature (37°C) after 1 min, 1-6 h and 12 h and on each day up to 1 week. The results were statistically evaluated by one-way analysis of variance and post hoc Tukey's tests. Results: The TAED groups demonstrated significantly higher amounts of released oxygen after 1 min and 1 h at 25°C and 1 min at 37°C (P < 0.05). At all other measurement times, the amount of TAED in each mixture did not alter the amount or speed of oxygen release (P > 0.05). Conclusions: Tetra acetyl ethylene diamine groups achieved their maximum oxygen release 2 h earlier at 25°C and 1 h earlier at 37°C than the other groups. Thus, TAED accelerated oxygen release from sodium perborate-distilled water mixtures regardless of its proportions up to 24 h. © 2008 International Endodontic Journal.
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    Shear bond strength of different adhesives to Er:YAG laser-prepared dentin
    (2006) Çelik E.U.; Ergücü Z.; Türkün L.S.; Türkün M.
    Purpose: The aim of this study was to examine the influence of Er:YAG laser on the shear bond strength of three different adhesives to lased dentin. Materials and Methods: Seventy specimens obtained from 35 extracted human molars were embedded in polyester resin and ground with silicon carbide papers. The samples were divided into seven groups. 1. Er:YAG laser (Key Laser 3, KaVo) + Clearfil Protect Bond (Kuraray); 2. Er:YAG laser + Clearfil tri-S Bond (Kuraray); 3. Er:YAG laser + 37% H3PO4 + Single Bond 2 (3M-ESPE); 4. Er:YAG laser + Single Bond 2; 5. conventional method + Clearfil Protect Bond; 6. conventional method + Clearfil tri-S Bond; 7. conventional method + 37% H3PO4 + Single Bond 2. The samples were subjected to shear bond testing 24 h after bonding. Statistical analyses were carried out by two-way ANOVA, t-test, one-way ANOVA, post-hoc Tukey's and Dunnett C test (p = 0.05). Results: Only the Er:YAG laser + Clearfil tri-S Bond group demonstrated significantly higher bond strengths vs conventionally prepared specimens (p < 0.05). There were no significant differences between the shear bond strengths of Single Bond 2 adhesive applied to laser- vs bur-treated specimens (p > 0.05). In laser prepared samples, Clearfil Protect Bond showed the highest scores (p < 0.05), whereas in conventionally prepared groups, no statistical differences were observed between Clearfil Protect Bond and Clearfil tri-S Bond (p > 0.05). Conclusion: Er:YAG laser irradiation did not adversely affect the shear bond strength of Single Bond 2 and Clearfil Protect Bond to dentin, whereas it increased the shear bond strength values of Clearfil tri-S Bond.