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Öğe Antibacterial effect of dental cements evaluated using agar diffusion test(Taylor & Francis Ltd, 2015) Dündar, Ayşe; Karaçam, Nejla; Yavuz, Tevfik; Öztürk, Nilgün; Pınarkara, YaseminPurpose: Secondary caries can occur around the restoration, fixed prosthesis, and orthodontic band margins because of cariogenic bacteria. Long-lasting antibacterial effectiveness of dental cements used contemporarily can reduce this phenomenon. The purpose of this study was to examine the antibacterial activities of nine dental cements (BisCem((R)), Super-Bond C&B, Rely X-TM, Panavia(TM) F 2.0, Variolink((R)) II, Unitek(TM) Multi Cure, Multilink((R)) Automix, Clearfil(TM) Esthetic Cement, Transbond(TM) LR) using agar diffusion test. Materials and methods: The test materials were inserted into the wells of Muller Hinton agar plates inoculated with Streptococcus mutans and Streptococcus salivarious. The diameters of the inhibition zones produced around the materials were measured after 24h of incubation. Two-Way ANOVA, the Kruskal-Wallis, and the Mann-Whitney U tests at a significance level of pResults: Unitek Multi Cure cement exhibited a significant difference from the control group against both S. mutans and S. salivarious (p<0.05). While the zone of inhibition of Unitek Multi Cure cement was shorter (8.50 +/- 1.77) than the control group (12.63 +/- 1.30), Unitek Multi Cure had antibacterial effect against S. mutans and S. salivarious (p<0.05). S. mutans displayed a significantly lower resistance to Unitek Multi Cure, BisCem, and Superbond C&B than S. salivarious (p<0.05). Conclusion: Conventional glass ionomer cement, Unitek Multi Cure, exhibited greatest in vitro antibacterial activity against both S. mutans and S. salivarious. Formation of dental caries had been suppressed by the fluoride-releasing GICs.Öğe Bond strength of resin composite to light activated bleached enamel(Wolters Kluwer Medknow Publications, 2016) Yavuz, Tevfik; Özyılmaz, Özgün Yusuf; Öztürk, Atiye Nilgün; Aykent, FilizObjectives: This study evaluated the microtensile bond strength (mu TBS) of a resin composite bonded to bleached enamel as a function of bleaching conditions. Materials and Methods: The whiteness hydrogen peroxide (HP) bleaching agent containing 35% HP was applied to the central incisors' facial enamel surface and irradiated as follows: No treatment (G1; control); no light (G2); light-emitting diode, the 40s (G3); diode laser, the 20s (G4); and neodymium: yttrium aluminum garnet laser, 20s (G5). A Variolink II resin composite structure was then built up incrementally on the surface. The teeth were sectioned into three 1.2 mm x 1.2 mm wide "I"-shaped sections. The specimens were then subjected to microtensile testing at a crosshead speed of 1 mm/min. Data were analyzed using one-way ANOVA (alpha = 0.05) followed by the Tukey Honestly Significant Difference post-hoc test. The fractured surfaces were observed with a stereomicroscope at x 100 magnification. Results: One-way ANOVA revealed no statistical differences among the groups (P > 0.05). No differences appeared between the groups bonded 14 days after bleaching (P > 0.05). Mean mu TBS values (MPa) were as follows: 22.05 +/- 5.01 (G1); 19.6 +/- 5.6 (G2); 19.3 +/- 5.4 (G3); 20.08 +/- 2.08 (G4); and 18.1 +/- 4.8 (G5). Many adhesive failures occurred at the bleached and irradiated enamel surfaces. Conclusion: The various irradiation treatments following the application of the whiteness HP bleaching agent to enamel did not significantly reduce the mu TBS within a 14-day period.Öğe Doksisiklin-streptomisin tedavisi sonrası nükseden Brucella abortus'a bağlı brusella hepatiti(2007) Özdemir, Dvut; Küçükbayrak, Abdülkadir; Arabaci, Hakan; Yavuz, Tevfik; Şahin, Idris; Yildirim, Mustafa; Şencan, Irfan-Öğe Effect of different denture adhesives on retention of complete dentures: an in vivo study(Taylor & Francis Ltd, 2017) Yeğin, Elif; Akpınar, Yusuf Ziya; Yavuz, Tevfik; Aslan, Muhammed AliThe increase in prevalence of tooth loss with the effect of population aging produces the growing need for complete dentures. The success and acceptance of complete dentures by the patient depends on sufficient retention and stability. Therefore, denture adhesives are regularly used by denture wearers to improve the function of complete denture. We evaluated the effect of three different denture adhesives (Corega, Protefix, Fittydent) on the retention of maxillary complete denture (MCD) using with digital dynamometer (DD). For this purpose, denture adhesives were applied on MCDs of 30 participants. After chewing procedure, the force was applied at 45 degrees to the palatal surface of denture by DD. Dislodgement force was recorded by means of Newton. There were four measurements on each patient including; group of control: Group C; Group CR: Corega; Group F: Fittydent; Group P: Protefix. The result of the study was statistically evaluated by using analysis of variance (ANOVA) and Tukey HSD test. Statistics of ANOVA showed a significant difference among all the four groups (p=0.00, <0.05). Tukey HSD test indicated that there was a statistical difference between Group F and the other groups, but there was not a significant difference between the other groups. The highest adhesive strength value was observed in group F, the lowest in group C. Use of denture adhesives improved the retentive strength of complete denture.Öğe Effect of different surface shapes formed by femtosecond laser on zirconia-resin cement shear bond strength(Taylor & Francis Ltd, 2015) Akpınar, Yusuf Ziya; Yavuz, Tevfik; Aslan, Muhammed Ali; Kepceoğlu, Abdullah; Kılıç, Hamdi ŞükürObjective: The purpose of this study was to evaluate the effect of different surface shapes formed by femtosecond (FS) laser on zirconia (Y-TZP)-resin cement shear bond strength (SBS). Background data: All ceramic restoration is used as an alternative to metal-ceramic restorations, due to its better aesthetics, strength, and toughness properties. However, bond strength of restoration to tooth and other materials is effective to long term success of the restoration, and to achieve it surface treatment is required on ceramic surface. Materials and methods: Forty square-shaped zirconia samples were prepared and assigned to four groups of 10. The details of the groups are as follows: Group A, square-shaped recessed surface; Group B, square-shaped projection surface; Group C, circular-shaped recessed surface; Group D, circular-shaped projection surface. The SBSs values were performed with a universal testing machine at a crosshead speed of 1mm/min. The data were analyzed statistically using analysis of variance (ANOVA) and Tukey HSD multiple comparisons tests. Results: The one-way ANOVA results on SBSs of the zirconia material bonded with resin cement revealed significant differences among the groups (p<0.05). The Tukey HSD test results revealed that Group B and D had significantly higher SBS values than other groups (p<0.05), but there were no significant differences between each other (p>0.05). Additionally, Group A and C had significantly lower values than other groups (p<0.05). Conclusions: Different surface shapes formed by FS laser provided a significant increase in SBSs. The SBS values of projection surfaces of circular and square-shapes are greater than that of recessed surfaces of circular and square-shapes.Öğe Effect of different surface treatments on porcelain-resin bond strength(Wiley, 2017) Yavuz, Tevfik; Özyılmaz, Özgün Yusuf; Dilber, Erhan; Tobi, Elif Sümeyye; Kılıç, Hamdi ŞükürPurpose:The aim of this study was to evaluate the effects of various surface treatments on the surface structure and shear bond strength (SBS) of different ceramics. Materials and Methods: total of 192 disk-shaped cores were prepared using two all-ceramic systems, of which 168 were submitted to SBS tests, and 24 were investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The ceramics used were IPS Empress e.max (EX) lithium glass-ceramic and Vita In-Ceram Zirconia glass-infiltrated zirconia (ICZ). The specimens were randomly divided into seven groups (n = 12) on the basis of the surface treatment used: control; SB-sandblasting with 50 mu m Al2O3 particles; CJ-chairside silica coating with 30 mu m SiO2 particles and silanization (Clearfil Porcelain Bond Activator); HF-etching in 5% hydrofluoric acid and silanization; ER-etching with an Er:YAG laser (10 W); ND-Nd:YAG laser etching (0.8 W); and FS-etching with a femtosecond laser (860 mW). A luting cement (Clearfil Esthetic) was photopolymerized on each treated ceramic disk. After subjecting the specimens to thermocycling (1000 cycles, 5 degrees C to 55 degrees C), SBS tests were performed using a universal testing machine. The data were analyzed with two-way ANOVA and Tukey's tests using a significance limit of 5%. Results: ong the EX ceramics, the CJ (29.10 MPa) and HF (26.07 MPa) specimens had statistically higher SBS values. For the ICZ ceramics, the highest value (28.08 MPa) was obtained for the CJ specimens. Conclusions: lanization after coating with silica improves the bond strengths of both EX and ICZ specimens, while HF etching is favorable only for the EX specimens.Öğe Effect of femtosecond laser beam angle on bond strength of zirconia-resin cement(Springer London Ltd, 2015) Akpınar, Yusuf Ziya; Kepçeoğlu, Abdullah; Yavuz, Tevfik; Aslan, Muhammed Ali; Demirtağ, ZülfikarYttrium-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramic is widely used as an all-ceramic core material because of its enhanced mechanical and aesthetic properties. The bond strength of Y-TZP restorations affects long-term success; hence, surface treatment is required on ceramic boundaries. This study evaluated the effect of different laser beam angles on Y-TZP-resin cement shear bond strength (SBS). Forty plates of Y-TZP ceramics were randomly assigned to four groups (n = 10). A femtosecond amplifier laser pulse was applied on Y-TZP surface with different incidence angles (90A degrees, 75A degrees, 60A degrees, 45A degrees). The resin cement was adhered onto the zirconia surfaces. The SBS of each sample was measured using universal testing machine at crosshead speed of 1 mm/min. The SBS was analyzed through one-way analysis of variance (ANOVA)/Tukey tests. The results showed that the degree of laser beam angle affects the SBS of resin cement to Y-TZP. The laser beam was applied to a surface with a 45A degrees angle which resulted in significantly higher SBS (18.2 A +/- 1.43 MPa) than other groups (at 90A degrees angulation (10.79 A +/- 1.8 MPa), at 75A degrees (13.48 A +/- 1.2 MPa) and at 60A degrees (15.85 A +/- 0.81 MPa); p < 0.001). This study shows that decreasing of the angle between the ceramic surface and the laser beam increased the SBS between the resin cement and the ceramic material, as well as the orifice.Öğe Effect of femtosecond laser treatment on the shear bond strength of a metal bracket to prepared porcelain surface(Mary Ann Liebert, Inc, 2015) Akpınar, Yusuf Ziya; Irgın, Celal; Yavuz, Tevfik; Aslan, Muhammed Ali; Kılıç, Hamdi Şükür; Üşümez, AslıhanObjective: The aim of this study was to investigate the effects of femtosecond laser treatment (Group FS) on the shear bond strength (SBS) of a metal bracket to prepared porcelain surface, and to compare it with other surface treatment techniques [50 mu m Al2O3 sandblasting (Group SB), 9.6% hydrofluoric acid gel (Group HF), and neodymium-doped yttrium aluminium garnet (Nd:YAG laser) (Group NY)]. Background data: Because of the increasing number of adult patients in current orthodontic practice, achieving sufficient bond strength of composite resin to porcelain restorations without bond failure during the treatment is a challenge for orthodontists. Methods: In total, 80 glazed feldspathic porcelain samples were prepared and randomly assigned to four groups of 20. Treated surfaces were treated with a silane agent. Brackets were bonded to porcelain samples. The specimens were stored in distilled water for 24 h and then thermocycled for 500 cycles between 5 degrees and 55 degrees C. The SBS of the brackets was tested with a universal testing machine at a crosshead speed of 1 mm/min, until bonding failure occurred. The data were analyzed statistically using analysis of variance (ANOVA) and Tamhane multiple comparisons tests. The results of ANOVA indicated that the SBS values varied according to the surface treatment method (p<0.001). Results: Results of the Tamhane post-hoc tests indicated that the bond strength in Group NY (5.11 +/- 1.53) was significantly lower than the other groups (p<0.05). There were no statistically significant differences among Groups SB (9.07 +/- 3.76), HF (9.09 +/- 3.51), and FS (11.58 +/- 4.16) (p=0.28). Conclusions: The results of this study showed that FS treatment produced high SBS of the processes assessed; therefore, it appears to be an effective method for bonding orthodontic metal brackets to prepared porcelain surfaces.Öğe The effect of silane applied to glass ceramics on surface structure and bonding strength at different temperatures(Korean Acad Prosthodontics, 2016) Yavuz, Tevfik; Eraslan, OğuzPURPOSE. To evaluate the effect of various surface treatments on the surface structure and shear bond strength (SBS) of different ceramics. MATERIALS AND METHODS. 288 specimens (lithium-disilicate, leucite-reinforced, and glass infiltrated zirconia) were first divided into two groups according to the resin cement used, and were later divided into four groups according to the given surface treatments: G1 (hydrofluoric acid (HF)+silane), G2 (silane alone-no heat-treatment), G3 (silane alone-then dried with 60 degrees C heat-treatment), and G4 (silane alone then dried with 100 degrees C heat-treatment). Two different adhesive luting systems were applied onto the ceramic discs in all groups. SBS (in MPa) was calculated from the failure load per bonded area (in N/mm(2)). Subsequently, one specimen from each group was prepared for SEM evaluation of the separated-resin ceramic interface. RESULTS. SBS values of G1 were significantly higher than those of the other groups in the lithium disilicate ceramic and leucite reinforced ceramic, and the SBS values of G4 and G1 were significantly higher than those of G2 and G3 in glass infiltrated zirconia. The three-way ANOVA revealed that the SBS values were significantly affected by the type of resin cement (P<.001). FIN ceramics had the highest rate of cohesive failure on the ceramic surfaces than other ceramic groups. AFM images showed that the surface treatment groups exhibited similar topographies, except the group treated with HF. CONCLUSION. The heat treatment was not sufficient to achieve high SBS values as compared with HF acid etching. The surface topography of ceramics was affected by surface treatments.Öğe Effects of different demineralization-inhibiting methods on the shear bond strength of glass-ceramics(Wiley, 2015) Dilber, Erhan; Akın, Mehmet; Yavuz, Tevfik; Erdem, AliPurposeThis in vitro study was undertaken to evaluate the effects of different demineralization-inhibiting methods on the shear bond strength (SBS) of glass-ceramics. Materials and MethodsNinety extracted intact human mandibular lateral insicors were randomly divided into six equal groups. Group C was left untreated, while enamel subsurface demineralization was induced in the other groups. In group D, porcelain discs (3 mm in diameter) were cemented to demineralized enamel by using total-etch photopolymerizing luting composite resin without pretreatment. Demineralized specimens in groups F, CA, M, and I were pretreated with fluoride gel, CPP-ACP paste, microabrasion, and resin infiltration, respectively, and then porcelain discs were cemented. SBS (MPa) was calculated from the failure load (N) per bonded area (mm(2)). Fracture types were examined by optical microscopy (40x magnification). Data were analyzed with ANOVA, Tukey's test, and G-test. ResultsANOVA revealed significant intergroup differences (p < 0.01). No significant differences in SBS (MPa) were found between groups C (19.48 2.0) and I (20.02 +/- 1.6). Lower SBS values were recorded in groups D (7.93 +/- 0.8), F (12.51 +/- 1.5), CA (17.08 +/- 1.3), and M (14.84 +/- 1.4). Mixed and cohesive failures were the most prevalent in groups M and I, respectively. ConclusionResin infiltration enhanced the SBS of porcelain discs bonded to demineralized enamel when compared with the other demineralization-inhibiting methods. Clinical Relevance: Resin infiltration could be useful to enhance adhesion of glass-ceramics to teeth with white spot lesions.Öğe Effects of melatonin on Candida sepsis in an experimental rat model(Springer, 2007) Yavuz, Tevfik; Kaya, Demet; Behçet, Mustafa; Öztürk, Elif; Yavuz, ÖzlemAs an immunomodulator, melatonin reportedly exhibits protective effects in severe sepsis/shock induced by bacterial lipopolysaccharides in animal models. The present study was conducted to evaluate the possible protective effects of melatonin against experimental Cindida sepsis in rats. A total of 40 adult male Wistar rats were randomly assigned to 4 groups: control, melatonin-treated control, septic, and melatonin-treated septic. Melatonin (200 mu g/kg/d, intraperitoneally) injections were begun a week prior to sepsis induction and were continued daily for 3 wk until the end of the study. Cyclophosphamide was administered to animals in all groups as an immunosuppressive agent as a single dose 4 d prior to yeast inoculation. To cause sepsis, the Candida albicans (ATCC 10259) strain was administered intravenously. Amphotericin B was given as an antimycotic therapeutic agent as a single dose to septic rats. Plasma levels of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), vascular cell adhesion molecule-1, and E-selectin were measured on the first and 15th days of sepsis. L-6, TNF-alpha, vascular cell adhesion molecule-1, and E-selectin levels of septic rats were higher than those of controls. Melatonin reduced IL-6 levels and shortened time to improvement in animals with Candida sepsis. Levels of TNF-alpha and adhesion molecules in melatonin-treated septic rats were decreased compared with those in septic rats, but this difference was not statistically significant. In light of the current results, investigators conclude that melatonin may have therapeutic benefits in Candida sepsis and in classic antimycotic treatment because of its immune regulatory effects.Öğe Etiologic agents of cervicovaginitis in Turkish women(Saudi Med J, 2006) Öztürk, Cihadiye E.; Özdemir, İsmail; Yavuz, Tevfik; Kaya, Demet; Behçet, MustafaObjective: To investigate the distribution of microbiologic agents causing cervicovaginitis. Methods: We conducted the study between October 2002 and December 2004 in Abant Izzet Baysal University, Duzce School of Medicine Hospital, Turkey. The samples were obtained from the posterior vaginal fornix and cervix by swabs in 828 patients. Direct microscopic examination, culture and enzyme immune assay (EIA) methods were performed in all patients for diagnosis of microbiologic agents. Results: Gardnerella vaginalis (G. vaginalis) were diagnosed in 254 (30.7%) patients, Candida albicans (C. albicans) in 152 (18.4%), Candida glabrata (C. glabrata) in 36 (4.3%), Candida species in 52 (6.3%), Staphylococcus aureus (S. aureus) in 62 (7.5%), Streptococcus group B in 28 (3.4%), Escherichia coli (E. coli) in 42 (5.1%), Klebsiella species in 24 (2.9%), and Streptococcus group D in 8 (1%) patients in culture. Less frequent enterobacteria in 30 (3.6%) were: Pseudomonas species, Proteus species Enterobacter species, Hafnia alvei and Nonfermenter species. Neisseria gonorrheae (N. gonorrheae) was detected in one patient (0.1%) in culture. The Chlamydia trachomatis (C. trachomatis) antigen was detected by EIA methods in 130 (15.7%) patients and Trichomonas vaginalis (T vaginalis) was observed in 8 (1%) patients by direct microscopic examination. Conclusion: Performing the etiologic diagnosis of cervicovaginitis is necessary in order to take appropriate therapeutic and preventive measures. Therefore, we recommend G. vaginalis, C. albicans and C. trachoniatis should be investigated in patients having a diagnosis of cervicovaginitis in our population, since these were detected in a considerable number of cases. Additionally, C. glabrata and T vaginalis should be kept in mind as possible pathogens.Öğe An evaluation of the apical seal in oval-shaped root canals prepared with either self- adjusting files or protaper files(2014) Helvacıoğlu, Dilek Yiğit; Oruçoğlu, Hasan; Yavuz, Tevfik; Yavuz, Cavit Işık; Yılmaz, Ayça; Kaba, Yusuf Nuri; Özden, SametObjectives: This study aimed to evaluate the apical seal obtained with lateral compaction of gutta-percha in oval-shaped root canals prepared with either self-adjusting files or ProTaper Universal rotary files. Materials and Methods: Twelve pairs of extracted mandibular premolars with oval-shaped root canals were randomly divided into two groups. The first group was biomechanically prepared with ProTaper Universal files, while the self-adjusting file system was used in the second group. The roots were better filled using cold lateral compaction of gutta-percha. Apical microleakage was measured with the computerized fluid filtration method. The results were analyzed statistically using the Mann-Whitney U test. Results: All of the roots in both groups showed leakage. Group 1 demonstrated significantly less microleakage (p<0.05). Conclusions: Instrumentation of oval-shaped canals using a self-adjusting file system with cold lateral compaction of gutta-percha demonstrated significantly greater apical microleakage when compared to ProTaper Universal. The apical leakage with different filling techniques, combined with self-adjusting files, should be evaluated in further studies.Öğe An evaluation of the apical seal in oval-shaped root canals prepared with either selfadjusting files or protaper files(Cumhuriyet University Faculty of Dentistry, 2014) Yigit, Dilek Helvacioglu; Orucoglu, Hasan; Yavuz, Tevfik; Yavuz, Cavit Isik; Yilmaz, Ayca; Kaba, Yusuf Nuri; Ozden, SametObjectives: This study aimed to evaluate the apical seal obtained with lateral compaction of gutta-percha in oval-shaped root canals prepared with either self-adjusting files or ProTaper Universal rotary files. Materials and Methods: Twelve pairs of extracted mandibular premolars with oval-shaped root canals were randomly divided into two groups. The first group was biomechanically prepared with ProTaper Universal files, while the self-adjusting file system was used in the second group. The roots were better filled using cold lateral compaction of gutta-percha. Apical microleakage was measured with the computerized fluid filtration method. The results were analyzed statistically using the Mann-Whitney U test. Results: All of the roots in both groups showed leakage. Group 1 demonstrated significantly less microleakage (p<0.05). Conclusions: Instrumentation of oval-shaped canals using a self-adjusting file system with cold lateral compaction of gutta-percha demonstrated significantly greater apical microleakage when compared to ProTaper Universal. The apical leakage with different filling techniques, combined with self-adjusting files, should be evaluated in further studies.Öğe In vivo evaluation of teicoplanin- and calcium sulfate-loaded PMMA bone cement in preventing implant-related osteomyelitis in rats(Esift Srl, 2006) Tüzüner, Tolga; Şencan, İrfan; Özdemir, Davut; Alper, Murat; Duman, Seçkin; Yavuz, Tevfik; Yıldırım, MustafaThe objective of this study was to evaluate the efficacy of teicoplanin- and calcium sulphate-loaded polymethylmethacrylate (PMMA) bone cements in preventing experimental implant-related osteomyelitis in rats. Four groups of antibiotic-loaded rods were prepared and were implanted into the lateral condylus of the rat femur after inoculation of Staphylococcus aureus. The effectiveness of these were assessed microbiologically, radiographically, and histopathologically. Radiographic evaluation revealed a significant reduction of periostal reaction and osteolysis in rats that received calcium sulphate- and teicoplanin-loaded rods. Histopathological evaluation confirmed these results. Acute infection and bone necrosis were found to be significantly lower in rats that had received calcium sulphate- and teicoplanin-loaded rods. The addition of calcium sulfate to teicoplanin-loaded PMMA bone cement appeared satisfactory as an antibiotic-carrying system for prophylaxis of experimental implant-related osteomyelitis, but further investigations are needed to reach definitive statements for clinical applications.Öğe Porcelain laminate veneer conditioning for orthodontic bonding: SEM-EDX analysis(Springer London Ltd, 2015) Aksakallı, Sertaç; İleri, Zehra; Yavuz, Tevfik; Malkoç, Meral Arslan; Öztürk, NilgünThe purpose of this in vitro study was to evaluate and compare the effects of different surface treatments and laser irradiation on the bond strength of brackets bonded to porcelain laminate veneer. Porcelain laminate veneer specimens were embedded in the centers of acrylic resin blocks. Thirty-nine teeth were used for shear bond strength testing and the remaining three (one tooth for each group) were used for evaluation of the debonded bracket interface. Specimens were randomly divided into three groups, each containing 13 specimens. The details of the groups are as follows: Group SB, sandblasting with alumina particles (50 mu m); Group HFA, 9.6 % hydrofluoric acid etching; Group ER, erbium-doped yttrium-aluminum-garnet (Er: YAG) irradiation (from 1 mm distance, 2 W, 10 Hz for 10 s). After conditioning, the upper central brackets were bonded to the porcelain surfaces. Porcelain laminate veneers were examined under stereomicroscope for adhesive remnant index and surface damage after debonding. The highest shear bond strength values were obtained with Group HFA (10.8 +/- 3.8 MPa) and Group ER (9.3 +/- 1.5 MPa), whereas Group SB revealed the lowest values. Scanning electron microscopy energy-dispersive X-ray (SEM-EDX) analysis revealed that the silicon level in the porcelain decreased after debonding in all groups. The sandblasting method did not demonstrate any ideal bond strength values; however, the 9.6 % hydrofluoric acid etching and Er: YAG laser did. There were no significant differences among all groups in terms of laminate surface damages. The Er: YAG laser therefore can be selected for ideal bond strength and minimal damage to porcelain laminates.Öğe Pseudomonas aeruginosa izolatlarının antibiyotiklere direnç oranlarının yıllar içinde değişimlerinin izlenmesi(2006) Yücel, Muhterem; Yavuz, Tevfik; Kaya, Demet; Behçet, Mustafa; Öztürk, C.Elif; Şahin, İdrisHastane infeksiyonu etkenlerinden olan Pseudomonas aeruginosa birçok antibiyotiğe karşı hızla geliştirdikleri çoğul ilaç direnci ile güncel bir sorun olarak önemlerini sürdüren mikroorganizmalardır. Bu retrospektif çalışmada servis ve yoğun bakım hastalarının çeşitli örneklerinden son üç yılda elde edilen, infeksiyon etkeni ya da kolonizan olarak düşünülen toplam 265 P.aeruginosa suşunun antibiyotiklere direnç oranlarının irdelenmesi amaçlanmıştır. P.aeruginosa suşları API ID32 GN (BioMerieux, Fransa) kiti kullanılarak tanımlanmıştır. İzole edilen suşların antibiyotik duyarlılıkları CLSI (eski adı:NCCLS) kurallarına uygun olarak Kirby-Bauer disk difüzyon yöntemiyle araştırılmıştır. İstatistiksel değerlendirme X2 (Chi-square) testi ile yapılmıştır. Suşların tümünde; % 26 amikasin, % 42 gentamisin, % 40 seftazidim, % 34 sefepim, % 31 imipenem, % 35 aztreonam, % 29 piperasilin/tazobaktam ve % 30 siprofloksasin direnci gözlenmiştir. Çalışma sonuçlarımıza göre 2005 yılında amikasine karşı direnç oranı azalırken, seftazidim, sefepim, piperasilin/tazobaktam, aztreonam ve siprofloksasin için direnç oranlarında 2003 yılına göre artışlar saptanmış ve bu farklar istatistiksel olarak anlamlı bulunmuştur (p<0.05-0.001).Öğe Push-out bonding strengths of four different dowel systems luted with two different adhesive systems(Taylor & Francis Ltd, 2014) Oruçoğlu, Hasan; Yavuz, Tevfik; Demir, Necla; Öztürk, Nilgün; Öztürk, BoraThis in vitro study investigates the bonding capacity of resin cements to dowels, using the push-out bonding strength of four different dowel systems, namely, stainless steel dowels (SSD), resin-supported polyethylene fiber dowels (RSPFD), zirconia dowels (ZD), and superpost glass fiber dowels (GFD), luted in root canals, using two different resin cements, namely, Multilink Automix Cement and Clearfil Esthetic Cement. Ninety-six maxillary central incisor teeth were sectioned below the cementoenamel junction, and the roots were treated endodontically. Then the roots were placed into four groups, based on the dowel systems used. The roots were further placed into two subgroups, based on the cement type used as subgroup A and subgroup B. Push-out bonding tests were performed on the bonded specimens, which were cut into 1mm thick sections. A two-way ANOVA test and Tukey's HSD tests were performed. The push-out bonding strength values for SSD, ZD, and RSPFD were not significantly different (p>0.05). The means for GFD were significantly higher than the means for ZD (p<0.05) when Multilink Automix Cement was used. However, when Clearfil Esthetic Cement was used, the means for RSPFD were significantly higher (p<0.001) than the means for the other systems. When Clearfil Esthetic Cement was used, the RSPF dowel system provided significantly higher bonding strength values than the other systems.Öğe Seroprevalence of varicella, measles and hepatitis B among female health care workers of childbearing age(Natl Inst Infectious Diseases, 2005) Yavuz, Tevfik; Özdemir, İsmail; Şencan, İrfan; Arbak, Peri; Behçet, Mustafa; Sert, ErhanTo evaluate the relation between infectious agents and reproductive health hazards for health care workers (HCWs), a cross-sectional study consisting of 73 HCWs and 65 bureau workers was conducted. The reproductive health problems of both groups were compared using a questionnaire, and serologic examinations for measles, varicella and hepatitis B were performed. There were no differences between the two groups according to the rate of seropositivity of measles and varicella (P > 0.05). The prevalence of anti-HBc seropositivity was significantly higher among HCWs than controls (31.5 versus 16.9%). There were no differences between seropositive and seronegative subgroups of measles, varicella and hepatitis B regarding the rates of normal delivery time, preterm and postterm delivery and stillbirth. Subjects seropositive for anti-HBc showed a higher spontaneous abortion rate than those who were seronegative (38.2 versus 16.3, P = 0.009). Although these data showed that HCWs had a high rate of anti-HBc seropositivity and that the rate of spontaneous abortion was associated with past hepatitis B virus infection, further studies including larger populations are needed. We considered that it should be strongly recommended that all HCWs be vaccinated against this virus, and future studies should be focused on the relationship between infectious diseases and reproductive health problems in HCWs.Öğe Temperature rises during tooth bleaching with different light-curing units(Taylor & Francis Ltd, 2015) Özyılmaz, Özgün Yusuf; Yavuz, Tevfik; Sarı, Tuğrul; Aykent, Filiz; Öztürk, Atiye NilgünThe aim of this study was to evaluate the influence of three different light-curing units on the temperature rise induced in the pulpal cavity, when bleached with 35% hydrogen peroxide (HP). Forty extracted maxillary central incisors were randomly divided into four groups according to photoactivation procedure (n=10). Whiteness HP (WHP) bleaching agent which contains 35% HP bleach was placed on the facial tooth surface and no photoactivation device was used (control); an blue light-emitting diode (LED, 40s), a diode laser (4W, Continous mode, 20s), and Nd:YAG laser (4W, 60Hz frequency, 20s). Temperature rise in the pulpal chamber was measured with a J-type thermocouple wire that was connected to a data logger before and immediately after each 20-40s application. One tooth of each group was selected for scanning electron microscope analysis. Data were analyzed using one-way ANOVA followed by the Games Howell post hoc test at a preset alpha of 0.05. One-way ANOVA revealed that there was a significant difference among the light-curing units (p<0.05) and between control group and light-curing units (p<0.05). The Nd:YAG induced significantly, which resulted in higher temperature increase than other light-curing units (10.7 degrees C). The LED unit produced the lowest temperature changes (3.2 degrees C) among the light-curing units. The presence of the bleaching gel did not cause a temperature increase in control group (0 degrees C). The results suggested that using light-curing units caused temperature changes in the intrapulpal cavity during tooth bleaching. The use of LED will be more safer for pulpal health when assisted with WHP bleaching gel.
