İstanbul Kent Üniversitesi Araştırma ve Akademik Performans Sistemi
DSpace@Kent, İstanbul Kent Üniversitesi’nin bilimsel araştırma ve akademik performansını izleme, analiz etme ve raporlama süreçlerini tek çatı altında buluşturan bütünleşik bilgi sistemidir.
Güncel Gönderiler
Öğe Türü:Öğe, Evaluation of the middle and inner ear functions of pregnant women(Türkiye Klinikleri, 2026) Türe, Leyla; Çağlar, Tuğçe Gül; Kaya, MesutObjective: Women’s’ daily lives may be affected during pregnancy. To ensure that this issue is not overlooked, hearing tests should be included in routine pregnancy check-ups at certain stages. This study aimed to investigate the effects of hormonal changes occurring during the 1st, 2nd, and 3rd trimesters of pregnancy on the middle and inner ear auditory system. Material and Methods: A total of 43 pregnant and 27 healthy non pregnant women were included in the study. After an otorhinolaryngology examination, all participants underwent pure tone audiometry between 125 8,000 Hz, acoustic immitance, and Transient Evoked-Otoacoustic Emission (TE-OAE) testing at 1,000-4,000 Hz. Results: In pure tone audiometry eval uations, bilateral hearing thresholds at 125, 250, and 500 Hz were found to be elevated in pregnant women across all trimesters compared with healthy controls. Additionally, the TE-OAE amplitude values decreased at 2,000, 3,000, and 4,000 Hz from the 1st to the 3rd trimester. This slight increase in low-frequency hearing thresholds resembles cochlear hearing loss and may be attributed to hormonal changes during pregnancy. Furthermore, the otoa coustic emission values at 2,000, 3,000, and 4,000 Hz were lower in preg nant women than in healthy women. Conclusion: On the basis of these results, normal findings regarding middle ear functions during pregnancy were observed, while physiological changes were noted in cochlear func tions.Öğe Türü:Öğe, Surface hardness ratios and surface roughness of bulk-fill resin composites following different heating protocols(Mosher and Linder, 2026) Kopuz, Dilan; Erçin, Özlem; Kocuk, Merve; Alkan, Elif; Korkut, Bora; Tağtekin, Dilek; Yanıkoğlu, FundaPurpose: To evaluate the impact of preheating on the physical properties of bulk-fill resin composites, with a particular focus on microhardness and surface roughness. Methods: In this study, seven bulk-fill resin composites (SonicFill 3, Opus Bulk-Fill Flow, Opus Bulk-Fill, Metafil Bulk-Fill, Tetric PowerFlow, Tetric N-Ceram, and Estelite Bulk-Fill Flow) and one conventional resin composite (Filtek Z250) were tested. Specimens were divided into two main groups: Group 1 (preheated 68°C for 10 minutes) and Group 2 (stored at room temperature). For each group, five disc-shaped resin composites (4 mm thickness x 5 mm diameter) were prepared. Each bulk-fill resin composite was applied in a single increment, whereas Filtek Z250 was placed in the molds in 2 mm layers. To complete the polymerization, the samples were kept in distilled water at 37°C for 24 hours. Then, the surfaces of the samples were polished with Twist Dia (Clearfil) polishing discs to imitate the finishing and polishing processes. Baseline microhardness and surface roughness values were measured. Subsequently, specimens underwent artificial aging simulating 2 years of clinical use (10,000 brushing cycles + 1,200 thermal cycles). Post-aging measurements were repeated, and statistical analyses were conducted. Results: Significant differences in microhardness values were observed among the experimental groups for all restorative materials, except for Estelite Bulk-Fill Flow (P> 0.05). The highest bottom-to-top hardness ratio was found in both preheated and non-preheated Opus Bulk-Fill Flow, while the lowest was observed in preheated Tetric PowerFlow. Microhardness generally decreased with depth, and the impact of preheating varied among materials. Post-aging surface roughness increased in all groups. Preheated Metafil Bulk-Fill exhibited the highest surface roughness, whereas Estelite Bulk-Fill Flow (both preheated and non-preheated) showed the lowest. Preheating reduced viscosity and enhanced microhardness in certain resin composites but also increased surface roughness over time. The effects of preheating are material-dependent due to compositional differences.Öğe Türü:Öğe, Effect of pre-diagnostic stain removal on the detection of occlusal fissure caries: A laboratory study(Mosher and Linder, 2026) Kocuk, Merve; Kopuz, Dilan; Alp, Şemsi; Kanar, Özlem; Erçin, Özlem; Korkut, Bora; Yılmaz Atalı, Pınar; Tağtekin, Dilek; Yanıkoğlu, FundaPurpose: To evaluate the laboratory cleaning efficacy of six commonly used non-invasive methods for removing stains from occlusal fissures before caries diagnosis. Methods: 60 extracted, caries-free permanent molars with visible occlusal staining were divided into six groups (n= 10): AquaCare air abrasion, Kerr prophylactic paste, Whiteness HP (35% H₂O₂), HealOzone, oxygenated water + pumice, and Opalustre. All samples were analyzed pre- and post-treatment using a dental microscope, Diagnodent Pen, QLF imaging (Qraypen), 3D Geomagic Control X software for volumetric evaluation and photo editing software for pixel evaluation. Statistical analyses were performed with Kruskal-Wallis and the Friedman’s two-way ANOVA test (P< 0.05). Results: All methods significantly reduced surface discoloration (P< 0.05). AquaCare showed the least residual staining, while HealOzone had the highest (P= 0.043). Volumetric analysis revealed no intergroup enamel loss (P> 0.05), although a significant change was noted in the Whiteness HP group (P= 0.017). QLF parameters (ΔF and ΔQ) improved significantly in Aquacare, HealOzone, and Opalustre (P< 0.05). Diagnodent Pen readings decreased significantly in the Aquacare, Kerr paste, HealOzone, and oxygenated water + pumice groups (P< 0.05). All tested methods effectively removed fissure stains without causing measurable enamel loss. HealOzone, Aquacare, and Opalustre demonstrated the most balanced performance, combining high cleaning efficacy with minimal surface alteration. The findings emphasize the value of multimodal, minimally invasive approaches for optimizing diagnostic accuracy in occlusal fissure caries detection.Öğe Türü:Öğe, Effects of hardness and surface pretreatment on the bond strength of a polyvinylsiloxane attachment matrix to denture base resin(Elsevier, 2026) Gürel, Anıl; Kaffaf, Mehmet Berk; Gençel, Burç İhsan; Şakar, OlcayPolyvinylsiloxane (PVS) matrices are used in implant-supported overdentures; however, detachment from the denture base remains a common complication. This in- vitro study evaluated the effects of matrix hardness and surface pretreatment on the tensile bond strength of a PVS matrix to denture base resin. A total of 144 specimens were prepared using a PVS attachment-matrix system in 3 different Shore A hardness (SH) values (SH25, SH50, and SH65) and 3 acrylic resin surface pretreatment (phosphoric acid etching, monomer application, and combined acid–monomer) and control groups. Specimens were fabricated using a computer numerical control (CNC)–milled brass mold. Bonding surfaces were grit-blasted with 110 μ primer, and subjected to 1000 thermocycles between 5 ◦ C and 55 ◦ m aluminum oxide particles, treated with a manufacturer-recommended C. Tensile bond strength was measured using a universal testing machine, and failure modes were classified as adhesive, cohesive, or mixed. Data were analyzed using two-way ANOVA and Tukey HSD post hoc test ( α = 0.05). Both matrix hardness and surface pretreatment significantly affected bond strength (P < 0.05). The SH50 group demonstrated the highest bond strength, whereas the SH25 group showed the lowest values. Phosphoric acid significantly increased bond strength only for the SH25 group, while monomer application improved bond strength across all hardness groups. In contrast, the combined acid–monomer pretreatment significantly reduced bond strength in all groups. These findings suggest that bond strength is not directly proportional to matrix hardness and suggest an optimal hardness range, highlighting the influence of matrix hardness–surface pretreatment interactions.Öğe Türü:Öğe, Development and psychometric evaluation of chronic obstructive pulmonary disease empowerment scale (COPD-ES)(Springer Publishing Company, 2026) Aksoy, Zahide; Erol, Saime; Oruç, ÖzlemBackground and Purpose Patient empowerment is essential for effective self-management and person-centered care in chronic obstructive pulmonary disease (COPD). However, disease-specific instruments for assessing empowerment remain limited. This study aimed to develop the Chronic Obstructive Pulmonary Disease Empowerment Scale (COPD-ES) and evaluate its psychometric properties. Methods A cross-sectional study was conducted with 275 individuals with COPD. Content validity was assessed using expert evaluation. Construct validity was examined through exploratory and confirmatory factor analyses. Internal consistency and test–retest reliability were evaluated to determine the reliability of the scale. Results The final scale consisted of 24 items across five factors (awareness, knowledge, partnership, choice, and self-efficacy), explaining 61.78% of the total variance. Confirmatory factor analysis indicated acceptable model fit (χ²/df = 1.81, RMSEA = 0.055, CFI = 0.93, NFI = 0.92, SRMR = 0.06). The overall Cronbach’s alpha coefficient was 0.90, and subscale alpha values ranged from 0.69 to 0.93. Test–retest reliability was strong (ICC = 0.85). Conclusions The COPD-ES is a valid and reliable disease-specific instrument for assessing empowerment in individuals with COPD. It may support nurses in identifying domain-specific empowerment needs and guiding tailored, person-centered interventions.
