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Now showing 1 - 10 of 35
  • PublicationOpen Access
    Effect of polymerization time and home bleaching agent on the microhardness and surface roughness of bulk-fill composites: A scanning electron microscopy study
    Objective: The aim of this study is to evaluate the microhardness and surface roughness of two different bulk-fill composites polymerized with light-curing unit (LCU) with different polymerization times before and after the application of a home bleaching agent. Materials-methods: For both microhardness and surface roughness tests, 6 groups were prepared with bulk-fill materials (SonicFill, Filtek Bulk Fill) according to different polymerization times (10, 20, and 30 s). 102 specimens were prepared using Teflon molds (4 mm depth and 5 mm diameter) and polymerized with LCU. 30 specimens (n = 5) were assessed for microhardness. Before home bleaching agent application, the bottom/top (B/T) microhardness ratio was evaluated. After bleaching agent application, the microhardness measurements were performed on top surfaces. Roughness measurements were performed in 72 specimens (n = 12) before and after bleaching application. Additionally, for SEM analyses, two specimens from all tested groups were prepared before and after bleaching agent application. The data B/T microhardness ratio before bleaching was analyzed by two-way ANOVA and Tukey's HSD test. The data from the top surface of specimens' microhardness before and after bleaching were analyzed using Wilcoxon signed-rank test, Kruskal-Wallis, Mann-Whitney U tests. The data from surface roughness tests were statistically analyzed by multivariate analysis of variance and Bonferroni test (p < 0.05). Results: The B/T microhardness ratio results revealed no significant differences between groups (p > 0.05). Comparing the microhardness values of the composites' top surfaces before and after bleaching, a significant decrease was observed exclusively in FB30s (p < 0.05). No significant differences in surface roughness values were observed when the groups were compared based on bulk-fill materials (p > 0.05) while the polymerization time affected the surface roughness of the SF20s and SF30s groups (p < 0.05). After bleaching, surface roughness values were significantly increased in the SF20s and SF30s groups (p < 0.05). Conclusion: The clinicians should adhere to the polymerization time recommended by the manufacturer to ensure the durability of the composite material in the oral environment.
  • PublicationOpen Access
    Impact of a Surface Sealant Application on the Color Stability of a Nano-hybrid Composite Resin
    (2021-12-01T00:00:00Z) Sarıalioğlu Güngör, Ayça; Dönmez, Nazmiye; Kahya, Deniz Selin; Hergüner Siso, Şeyda; SARIALİOĞLU GÜNGÖR, AYÇA; DÖNMEZ, NAZMİYE
    Objective: Mouthwashes containing chlorhexidine can cause discoloration in restorative materials when used for the long-term. To prevent staining of a restorative material, several protective materials are used. The aim of this in vitro study was to evaluate the impact of a surface sealant on the color stability of a nano-hybrid composite resin material immersed in different mouthwashes. Methods: A total of 42 composite resin discs (10x2 mm) were prepared with a nano-hybrid composite resin (Herculite XRV Ultra) using Teflon moulds. The composite specimens were first divided into two groups (with or without a surface sealant) then into three subgroups (n=7) according to the mouthwashes (Gengigel, Oderol, and Chlorhex). After SS application to 21 specimens, all the discs were subjected to baseline color measurements using a spectrophotometer according to the Commission Internationale de l’Eclairage L*a*b* system. The specimens underwent thermal cycling. Following immersion in different mouthwashes for 24 hours, the color measurements were repeated. The ∆E data were assessed using Kruskal-Wallis one-way ANOVA. Mann-Whitney U test was performed for different immersion mouthwashes (p<0.5). Results: Statistically significant differences (p<0.5) were found between the unsealed composite specimens immersed in Chlorhex and the other mouthwashes in terms of ∆E values. The Chlorhex appeared to be associated with the most severe alteration in color (5.14±0.83), followed by Gengigel (2.21±1.46) and Oderol (1.94±1.75). There were no statistically significant differences (p>0.05) between the sealed and unsealed composite specimens in terms of the color changes. Conclusion: The application of a low viscosity liquid surface sealant material did not show the expected effect on the color stability of a nano-hybrid composite resin in terms of three different mouthwashes.
  • PublicationOpen Access
    Perceptions of dental students towards online education during the COVID-19 pandemic
    (2021-12-01T00:00:00Z) Sarıalioğlu Güngör, Ayça; Şeşen Uslu, Yeşim; SARIALİOĞLU GÜNGÖR, AYÇA; DÖNMEZ, NAZMİYE
    Purpose: This study evaluated the usage habits, attitudes, and perceptions of undergraduate dental students toward distance (online) learning and identified variables related to those attitudes. Materials and methods: The study included 1,605 undergraduate dental students who participated voluntarily. The data collection tool consisted of a distance learning attitude scale, a questionnaire on personal information, and open-ended questions. The perceptions of dental students to distance education according to the year and type of dental school they attended were evaluated. Results: Most students expressed that distance learning in dental courses was not as effective as traditional face-to-face education (59.1%, n=949). While students studying at state universities had a more negative view of distance education, the satisfaction scores of the first-year students were found to be significantly lower than the other students (p<0.05). Conclusion: Dental students were generally unhappy with the interruption of traditional education caused by COVID-19 and having to continue their education online. However, under the circumstances, they saw it as an advantage allowing them to continue their education and avoid a complete suspension.
  • PublicationMetadata only
    Effect of thermal cycling on micro-tensile bond strength of composite restorations bonded with multimode adhesive
    (2015-04-18) Donmez, NAZMİYE; Siso, Seyda Herguner; ÜŞÜMEZ, Aslihan; Bayrak, Isil; DÖNMEZ, NAZMİYE
    Objective: The purpose of this in vitro study was to evaluate the effect of thermal cycling on the micro-tensile bond strength (Mtbs) of multimode adhesive agents. Materials and methods: Eight freshly extracted caries-free human third molars were used. The flat dentin surfaces were prepared and polished with 600-grit SiC abrasive paper for standard smear layer formation. The teeth were restored using Single Bond Universal Adhesive [(total etch (G1, G2)/self etch (G3, G4)] + Filtek Z550 and All-Bond Universal Adhesive [(total etch (G5, G6)/self etch (G7, G8)] + Aelite all-purpose. The specimens in groups G1, G3, G5, and G7 were subjected to thermal cycling (1000 cycles at 5-55 degrees C, for a 30 s dwell time), while the specimens in other groups were not exposed to an aging procedure. The Mtbs test was determined in all procedures. Data were submitted to three-way ANOVA and post hoc tests. The significance level was set at = 0.05. Results: Group five was highly affected by the thermal cycling following the total etch procedure, while group one was not significantly affected. Group seven was highly affected by thermal cycling, while group three was not significantly affected after the self etch procedure. Group eight exhibited a higher mean Mtbs value after the thermal cycling procedure. Conclusion: The bond strength of multimode (universal) adhesives was found to be material dependent. The total etch procedure showed a higher Mtbs value than the self etch procedure.
  • PublicationOpen Access
    Reactions of Subcutaneous Connective Tissue to Mineral Trioxide Aggregate, Biodentine (R), and a Newly Developed BioACTIVE Base/Liner
    (2020-05-01T00:00:00Z) Karabulut, Baris; DÖNMEZ, NAZMİYE; Goret, Ceren Canbey; Atas, Cafer; Kuzu, Ozlem; DÖNMEZ, NAZMİYE
    Aim. There is an increasing interest in the application of BioACTIVE materials to achieve hard tissue formation and maintain pulp vitality. Mineral trioxide aggregate (MTA) and Biodentine (R) are BioACTIVE materials used for pulp capping. Recently, dental researchers have produced BioACTIVE glass-incorporated light-curable pulp capping material. The study is aimed at evaluating the subcutaneous connective tissue reactions to MTA, Biodentine (R), ACTIVA BioACTIVE Base/Liner. These materials were placed in polyethylene tubes and implanted into the dorsal connective tissue of Sprague Dawley rats. The presence of inflammation, predominant cell type, calcification, and thickness of fibrous connective tissue was recorded by histological examination 7, 30, and 60 days after the implantation procedure. Scores were defined as follows: 0 = none or few inflammatory cells, no reaction; 1 = = 125 cells, severe reaction. Fibrous capsule thickness, necrosis, and formation of calcification were recorded. ANOVA and post hoc Dunnett-s tests were used for statistically analyses (p<0.05). Results. In terms of oedema, inflammation, fibrous capsule, and necrosis, no significant differences were found in any time period for any material. MTA and Biodentine (R) showed higher calcification than in the ACTIVA BioACTIVE on day 30, and the difference was statistically significant (p<0.05). After 60 days, while calcification was not seen in the control group, it was observed in the test groups. There was a statistically significant difference between the control and the others. Conclusion. All materials were well tolerated by the tissues in the 60-day evaluation period. One notable finding is the presence of dystrophic calcification in the connective tissue adjacent to the newly developed BioACTIVE Base/Liner material. Therefore, this new BioACTIVE Base/Liner material may be safely recommended to clinicians as a pulp capping material.
  • PublicationMetadata only
    Twelve-month Clinical Performance Evaluation of a Glass Carbomer Restorative System
    (2022-07-01T00:00:00Z) Kaynar, Zeynep Buket; Dönmez, Nazmiye; DÖNMEZ, NAZMİYE
  • PublicationMetadata only
    Bir Üniversitenin Girişimsel Olmayan Araştırmalar Etik Kuruluna Yapılan Başvurularda Eksiklikler ve Sıklıkla Yapılan Hatalar
    (2019-08-01) Meral, İsmail; Aştı, Türkinaz; Soysal, Ömer; Yıldırım, Nuran; Özçelik, Semra; Aydın, Teoman; Akbaş, Fahri; Temel, Binnur; Özder, Aclan; Büyükpınarbaşılı, Nur; Dönmez, Nazmiye; Alkaya, Mustafa Fırat; MERAL, İSMAİL; AŞTI, TÜRKINAZ; SOYSAL, ÖMER; YILDIRIM, NURAN; ÖZÇELİK, SEMRA; AYDIN, TEOMAN; AKBAŞ, FAHRİ; TEMEL, BİNNUR; ÖZDER, ACLAN; BÜYÜKPINARBAŞILI, NUR; DÖNMEZ, NAZMİYE
    Girişimsel olmayan araştırmalarda, ilgili etik kurulun onayını almadan çalışmalara başlamak mümkün değildir. Dünya Sağlık Örgütü-nün kurallarına göre, gerekli tüm belgeleri içeren başvuru dosyası ilgili Etik Kurula eksiksiz sunulmalıdır. Araştırmacıların başvuru dosyasındaki belgeleri eksiksiz tamamlamadaki isteksizliği, Etik Kurulların çalışma sürecini yavaşlatmakta ve hatta Etik Kurul ile araştırmacılar arasında tartışmaya bile neden olabilmektedir. Bu nedenle bu çalışma, bir üniversitenin Girişimsel Olmayan Araştırmalar Etik Kuruluna gönderilen proje başvuru dosyalarındaki eksiklikleri ve en çok yapılan hataları göstermek ve araştırmacılar için bir rehber oluşturmak amacıyla yapıldı. 24 Mart 2016 ve 30 Haziran 2018 tarihleri arasında Girişimsel Olmayan Araştırmalar Etik Kurula gönderilen başvuru dosyaları ve kararları ilgili etik kurulun veri tabanından analiz edildi. Başvuru dosyalarının revizyonuna neden olan en önemli gerekçeler, projenin amacının ilgili referanslar eşliğinde yeterince açıklanamaması ve özellikle iyi yazılamamış yöntem kısmı gibi başvuru formundaki eksikliklerdi. Araştırmacıları proje başvuru dosyası hazırlarken en çok yapılan hatalar hakkında eğitmek, Üniversite Etik Kurullarının gözden geçirme sürecinin verimliliğini ve hızını artıracaktır.
  • PublicationOpen Access
    Characterisationand microleakage of a new hydrophilic fissure sealent-Ultraseal XT®hydro™.
    sealant, UltraSeal XT® hydro™ (Ultradent Products, USA), and to investigate its in vitro resistance to microleakage after placement on conventionally acid etched and sequentially lased and acid etched molars. Material and Methods: The sealant was characterised by Fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and Vickers indentation test. Occlusal surfaces of extracted human molars were either conventionally acid etched (n=10), or sequentially acid etched and laser irradiated (n=10). UltraSeal XT® hydro™ was applied to both groups of teeth which were then subjected to 2,500 thermocycles between 5 and 55°C prior to microleakage assessment by fuchsin dye penetration. Results: UltraSeal XT® hydro™ is an acrylate-based sealant that achieved a degree of conversion of 50.6±2.2% and a Vickers microhardness of 24.2±1.5 under standard light curing (1,000 mWcm-2 for 20 s). Fluoride ion release is negligible within a 14-day period. SEM and EDX analyses indicated that the sealant comprises irregular submicron and nano-sized silicon-, barium-, and aluminium-bearing reduce microleakage (Mann-Whitney U test, p<0.001). The lased teeth presented enhanced
  • PublicationOpen Access
    Knowledge, stress levels, and clinical practice modifications of Turkish dentists due to COVID-19: a survey study
    (2021-03-01T00:00:00Z) Sarıalioğlu Güngör, Ayça; Dönmez, Nazmiye; Uslu, Yeşim Şeşen; SARIALİOĞLU GÜNGÖR, AYÇA; DÖNMEZ, NAZMİYE
    Dentists are exposed to the highest risk of occupational respiratory and droplet infections by working face-to-face with patients. The aim of this study was to investigate the knowledge of symptoms and modes of transmission of COVID-19, stress levels and clinical practice modifications of Turkish dentists during the COVID-19 pandemic. An online survey (15 questions) was sent to Turkish dentists from May 5 to 12 May, 2020. The survey comprised questions about dentists’ demographic characteristics, their knowledge about COVID-19, stress levels and the measures taken in dental clinics against COVID-19. This study included a total of 1,095 Turkish dentists. The data were expressed as frequency with percentage values for overall variables. Dentists were most familiar with high fever among the symptoms of COVID-19 (99.4%) and 99.2% of them reported that COVID-19 was transmitted with eye, mouth and nasal mucosa contact on surfaces contaminated with the droplets of infected persons. While the stress levels of females were higher than males, the stress levels of dentists with more than 20 years of professional experience were found to be lower. Regarding the precautions to be taken as a preventive measure when working again, 86.6% of the dentists took precautions by increasing daily patient care intervals and only 38.4% of the dentists wore an N95 mask. During this pandemic, knowing the conditions about when the treatments can be applied and the precautions to be taken will shed light on dentistry staff. Current recommendations of national authorities about the coronavirus should be followed.
  • PublicationMetadata only
    Çürük risk gruplarının belirlenmesinde beslenme alışkanlıklarının ve diyet kayıt analizlerinin rolü