Yazar "Uslu, Gulsah" seçeneğine göre listele

Listeleniyor 1 - 8 / 8
  • [ X ]
    Öğe
    Effect of Sodium Hypochlorite and EDTA on Surface Roughness of HyFlex CM and HyFlex EDM Files
    (Wiley, 2018) Uslu, Gulsah; Ozyurek, Taha; Yilmaz, Koray
    The aim of the present study was to compare the effect of exposure to sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) on the surface topography and roughness of HyFlex controlled memory (CM) and HyFlex electrical discharge machining (EDM) using atomic force microscopy (AFM). Twenty HyFlex EDM (25/.08) and 20 HyFlex CM (25/.06) files were divided into five groups (n = 4). One group served as a negative control group. The files in the other groups were exposed to 5.25% NaOCl and 17% EDTA solutions at 37 degrees C for 5 and 10 min, respectively, and examined using AFM after each exposure. The data were analyzed using one-way ANOVA test. The lowest values were observed in the control group of HyFlex EDM files (p < .05). The highest values were observed in the HyFlex EDM and HyFlex CM files immersed in EDTA for 10 min (p < .05). In conclusion, the tested irrigants had a significant negative effect on the surface porosity of NiTi files. The immersion of NiTi files in irrigants during cleaning and sterilization procedures results in corrosion and surface deformation of the files, and this can lead to unexpected file fracture during clinical use. Thus, the investigation of effect of ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite (NaOCl) on surface topography of HyFlex files is important.
  • [ X ]
    Öğe
    Fracture strength of endodontically treated teeth restored with different fiber post and core systems
    (Springer, 2020) Ozyurek, Taha; Topkara, Can; Kocak, Imran; Yilmaz, Koray; Gundogar, Mustafa; Uslu, Gulsah
    The aim of this study was to investigate the effects of different post and core systems, CAD/CAM crown placement on fracture strength of endodontically treated mandibular premolar teeth. One hundred forty single-rooted premolar teeth were randomly divided into a control group and six experimental groups as follows: control group (Group 1); FiberSite post luting with Clearfil DC Core Plus (Group 2); RelyX Fiber post luting and core build up with Clearfil DC Core Plus (Group 3); RelyX Fiber post luting with Clearfil DC Core Plus and core build up with Filtek Bulk Fill Posterior (Group 4); specimens that received CAD/CAM crowns after the same procedures performed in Groups 2, 3, and 4, respectively (Groups 5, 6, and 7). Fracture strength tests were performed, and the failure modes were recorded. Data were statistically analyzed using one-way ANOVA and post hoc Tukey tests. The highest fracture resistance was observed in the control group and among the experimental groups in Group 4. Groups 3 and 5 showed similar fracture resistance followed by Group 2. The lowest fracture resistances were seen in the samples of Groups 6 and 7. While the fracture strength of Group 2 increased after the crown placement (Group 5), the fracture strength of Group 3 and Group 4 decreased (P < 0.05). While the specimens in Groups 1, 2, 3, and 4 predominantly showed favorable failure, unfavorable failure was more frequent in Groups 5, 6, and 7.
  • [ X ]
    Öğe
    How does endodontic access cavity design affect the biomechanics of a maxillary premolar?? a finite element analysis study
    (Bmc, 2025) Uslu, Gulsah; Arican, Burcin; Gundogar, Mustafa; Ozyurek, Taha
    BackgroundThe aim of this study was to evaluate the effect of different endodontic access cavity designs on biomechanical properties of endodontically treated maxillary premolars under various static loads by finite element analysis method.MethodsBased on cone beam computed tomography data of maxillary first premolar, the models of endodontically treated teeth with traditional access cavity (TEC-I), traditional access cavity with Class-II mesio-occlusal cavity design (TEC-II), conventional access cavity (CEC), ninja access cavity (NEC), caries-driven access cavity (Cd-EC), buccal access cavity (BEC) and bucco-occlusal access cavity (BOEC). Three different static loads which were single-point vertical load (Static I), multi-point vertical load (Static II) and multi-point oblique load (Static III) were applied. The stress distribution and maximum Von Misses stress values were recorded.ResultsFor the enamel surface, the stress concentration was seen around the central fossa in Static I, on the marginal edge and palatal tubercle in Static II, and on the palatal cusp tip in Static III loads. For the dentin surface, the stress concentration was observed on pericervical area and buccal root surface in Static I, on all around the root surface in Static II, and on buccal and palatal root surfaces and furcation area in Static III loads. While the minimum stress distribution was detected in control group, followed by NEC and CEC designs, the maximum stress distribution was generally monitored in Cd-EC and TEC-II cavity designs.ConclusionThe increased tissue loss in maxillary premolars due to endodontic access cavity preparation meant the higher stress distribution on the tooth surface.
  • [ X ]
    Öğe
    Impact of Biodentine Placement on Fracture Resistance and its Influence on Discoloration with Different Scaffolds
    (Elsevier Science Inc, 2025) Sariyilmaz, Evren; Sariyilmaz, Oznur; Carikcioglu, Burak; Uslu, Gulsah; Alan, Raif
    Introduction: This study aimed to investigate the fracture resistance of teeth that underwent ex vivo regenerative endodontic treatment using Biodentine placed either above or below the cemento-enamel junction (CEJ). Additionally, it examined the impact of different placement approaches, in combination with various scaffold materials (blood, platelet-rich fibrin [PRF], injectable PRF [i-PRF]), on tooth discoloration over time. Methods: Thirty-nine human maxillary incisors were divided into three groups. The control group consisted of intact teeth. In the two experimental groups, regenerative endodontic procedures were simulated, and Biodentine was placed above or below the CEJ. Fracture resistance was evaluated after thermal and mechanical aging using a chewing simulator. In the discoloration test, 96 human maxillary incisor teeth were selected. Roots were sectioned 10 mm apical to the CEJ and canal enlargement was performed Gates-Glidden burs. Teeth were grouped according to the placement level of Biodentine (above or below CEJ) and the type of scaffold materials used (blood, PRF, i-PRF, distilled water). Discoloration was assessed by using a spectrophotometer at baseline, 1 week, 1 month, and 6 months. Data were analyzed using one-way analysis of variance followed by Tukey post hoc tests independent t-tests were used to evaluate the effect of placement location on color change. Results: The fracture resistance of intact teeth was significantly higher than that of the group in which Biodentine was placed below the CEJ. Blood and blood-derived products resulted in greater discoloration compared to distilled water, whereas PRF induced less discoloration than blood. Furthermore, the placement of Biodentine above the CEJ led to significantly less discoloration at specific time points compared to its placement below the CEJ. Conclusions: Positioning Biodentine above the CEJ may offer clinical advantages by potentially improving structural integrity while minimizing aesthetic concerns. When PRF is used as the scaffold material and Biodentine is placed coronally, tooth discoloration is minimized. (J Endod 2025;51:1199-1206.)
  • [ X ]
    Öğe
    Mechanical Properties of the New Generation RACE EVO and R-Motion Nickel-Titanium Instruments
    (Mdpi, 2022) Basturk, Fatima Betul; Ozyurek, Taha; Uslu, Gulsah; Gundogar, Mustafa
    This study aimed to evaluate and compare the dynamic cyclic fatigue, torsional and bending resistance of two novel RACE EVO (FKG Dentaire SA, La Chaux de Fonds, Switzerland) and R-Motion (FKG) nickel-titanium instruments with traditional RaCe (FKG) instruments. RACE EVO, R-Motion and RaCe instruments with a size of 25 and taper of 0.06 were used. A dynamic cyclic fatigue test was used to assess the time to fracture. The fractured surfaces were further analyzed using scanning electron microscopy at x350 and x3000 magnifications. A torsional resistance test was performed to measure the maximum torsional strength and angle of rotation. Phase transformations with temperature were evaluated using differential scanning calorimetry. The results were statistically analyzed with a Kruskal-Wallis test at a 5% significance level. R-Motion had the highest time to fracture and the lowest torsional and bending resistance, whereas RaCe had the lowest time to fracture and the highest torsional and bending resistance (p < 0.05). In relation to the angle of rotation, RACE EVO instruments had the highest deformation capacity followed by R-Motion and RaCe instruments (p < 0.05). The greater cyclic fatigue resistance and lower torsional and bending resistance results indicate that the novel R-Motion and RACE EVO instruments are less rigid and more flexible than RaCe instruments.
  • [ X ]
    Öğe
    Micro-CT evaluation of MTA compaction techniques in 3D-printed teeth with simulated perforating internal root resorption: an in vitro study
    (Bmc, 2025) Sariyilmaz, Oznur; Sariyilmaz, Evren; Uslu, Gulsah; Keskin, Cangul; Keles, Ali
    Background This study aimed to compare the effectiveness of manual compaction, indirect ultrasonic activation, and a novel sonic-activated endomotor in reducing voids during MTA placement in perforated internal root resorption cavities (IRR). Methods Thirty standardized 3D-printed resin teeth with simulated perforating IRR cavities (4 mm in diameter, located 4 mm from the apex, with a 2 mm buccal perforation) were fabricated. The samples were randomly divided into 3 groups: Manual compaction: MTA was placed and compacted using hand pluggers. Ultrasonic activation: MTA was placed and indirectly activated with an ultrasonic device at 30% power for 3 cycles of 10 s each. Sonic-activated endomotor: MTA was placed and compacted using the 812 MT endomotor. Specimens were stored at 37 degrees C in 100% humidity for 1-week. Micro-computed tomography (micro-CT) was used to evaluate the void volume. Intergroup comparisons were conducted using the Kruskal-Wallis test at a 5% significance level. Results The mean void volumes were 6.49 mm(3) in the manual compaction group, 2.61 mm(3) in the ultrasonic activation group, and 3.89 mm(3) in sonic-activated endomotor group. Although the manual compaction group exhibited the highest void volume, the differences among the groups were not statistically significant (P > 0.05). Conclusions Within the limitations of this in vitro study, all three MTA compaction techniques demonstrated comparable outcomes in the compaction of MTA in perforating IRR cavities. These findings suggest that, in such cases, the choice of technique may be guided by operator preference and clinical circumstances rather than expected differences in void reduction.
  • [ X ]
    Öğe
    Postoperative pain after SWEEPS, PIPS, sonic and ultrasonic-assisted irrigation activation techniques: a randomized clinical trial
    (Springer, 2022) Erkan, Erhan; Gundogar, Mustafa; Uslu, Gulsah; Ozyurek, Taha
    To investigate the efficacy of a new laser irrigation activation system [shock wave-enhanced emission photo-acoustic streaming (SWEEPS)] in terms of postoperative pain after primary root canal treatment compared with other techniques, namely photon-induced photo-acoustic streaming (PIPS), sonic system with EDDY, passive ultrasonic system (PUI), and manual dynamic activation (MDA). Two hundred patients with symptomatic irreversible pulpitis in mandibular premolar teeth were enrolled and randomly allocated to five different irrigation activation groups (n = 40) after chemo-mechanical root canal preparation. For irrigation activation, the SWEEPS and PIPS tips were attached to the Er-YAG laser system in the respective groups, while the Irrisafe tip was used in the PUI group and the EDDY tip in the sonic group. In the MDA group, irrigation was agitated with the master gutta-percha cone. At postoperative hours 8, 24, and 48 and on day 7, pain intensity was evaluated using the 10-mm Visual Analog Scale (VAS) and analgesic intake was recorded. The Kruskal-Wallis test was used to analyze the VAS scores, and pain prevalence and analgesic intake were examined with the Pearson's chi-square test at the 5% significance level. The PIPS and SWEEPS groups had the lowest level and prevalence of pain when compared to the remaining groups (P < 0.001). The PUI, sonic and MDA groups did not differ in terms of pain scores at hours 8 and 48 (P > 0.05). On day 7, the highest score and pain prevalence were recorded in the MDA group (P < 0.001). There was no difference between the groups in terms of analgesic intake (P > 0.05). Laser-activated irrigation systems provided lower postoperative pain scores and levels compared to the other activation systems. The MDA group had the highest pain scores and incidence at the end of the seventh day.
  • [ X ]
    Öğe
    Pull-out Retentive Resistance of Fiber Posts Restored with Different Core Materials
    (Galenos Publ House, 2022) Topkara, Can; Yilmaz, Koray; Gundogar, Mustafa; Uslu, Gulsah; Ozyurek, Taha
    Objective: This study aimed to assess the pull-out bonding resistance of FiberSite and RelyX Fiber posts constructed from core structures using various resin cement. Materials and Methods: Sixty mandibular premolar teeth were horizontally sectioned to create a root canal length of 15 +/- 1 mm. Up to size #40, samples were prepared and obturated with gutta-percha and root canal sealer. Three groups of specimens (n=20) were formed. FiberSite posts were luted and built-up using Clearfil DC Core Plus in Group 1, RelyX Fiber posts were luted and built-up using Clearfil DC Core Plus in Group 2, and RelyX Fiber Posts were luted and built-up using Filtek Bulk Fill Posterior in Group 3. Each specimen was vertically positioned in a universal testing machine and rotated at 0.5 mm/min until it dislodged. Oneway ANOVA and post hoc tests were used to evaluate the data. Results: The bonding strength of FiberSite posts was higher than that of RelyX Fiber posts (p<0.05). Clearfil DC Core Plus-built RelyX Fiber Posts exhibited higher bond strength than Filtek Bulk Fill Posterior-built posts (p<0.05). Conclusion: FiberSite posts provide better root canal dentin retention than RelyX Fiber posts with different core materials.