Hayriye Yasemin Yay Kuşçu

Aim: The aim of this in vitro study was to evaluate and compare the void volumes at the dentin–post interface when glass fiber posts were bonded using different resin cements, as assessed by 3D micro-computed tomography (µCT). Methodology: For this investigation, thirty extracted human maxillary central incisors with a single root were chosen. The specimens were divided into three groups at random (n = 10) and restored with glass fiber posts that were cemented using Variolink N, Panavia F 2.0, and RelyX Unicem resin cements, respectively. A resolution of 13.7 µm was used for high-resolution µCT scanning to obtain detailed images of the specimens. The Kruskal–Wallis test (post hoc: Mann–Whitney U with Bonferroni correction), the Friedman test, and the Spearman rank correlation test (α = 0.05) were used for statistical evaluation. Results: µCT analysis revealed that the mean total void volume at the dentin–post interface was 1.67 ± 0.69 mm³ for the Variolink N group, 2.59 ± 1.75 mm³ for the Panavia F 2.0 group, and 3.28 ± 2.13 mm³ for the RelyX Unicem group. The differences between the groups were statistically significant (p < 0.05), with the lowest void volume in the Variolink N group and the highest in the RelyX Unicem group. Within each group, void formation was distributed homogeneously across root levels (p > 0.05), whereas specimens cemented with RelyX Unicem showed significantly higher void formation in the apical third than the other two cements (p < 0.05). No correlation was found between empty canal volume or empty canal surface area and void volume (p = 0.34 and p = 0.19, respectively). Conclusion: Post-cementation analysis revealed significant differences in total void volume among the resin cements, whereas within-group regional comparisons did not yield statistically significant differences. Decementation of fiber posts is frequently associated with voids within the luting cement layer, so the choice of resin cement and its delivery technique remains clinically relevant.

The remarkable advancement of dental materials, treatment techniques, and prosthesis manufacturing processes has elevated computer-aided design and manufacturing (CAD/CAM) systems to a new level of clinical capability. Since its introduction to dentistry in the 1980s—beginning with the chairside CEREC system and the Procera framework concept—CAD/CAM has reshaped contemporary practice by enabling aesthetic, durable, and reliably reproducible restorations while transforming the way laboratories design and fabricate both framework (substructure) and monolithic restorations. Because the production stages are tightly controlled and the material blocks are industrially processed, modern CAD/CAM materials also offer improved structural properties—reduced microporosity, greater homogeneity, and lower firing shrinkage—relative to conventionally processed ones, while reducing laboratory steps, working time, and the overall error rate. This narrative review examines the principal CAD/CAM restorative materials, the digital data-processing workflow, and restoration production methods, together with their influence on marginal fit. The main material classes are described—leucite- and lithium-disilicate-reinforced glass ceramics, yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) and monolithic zirconia, resin-matrix and nanoceramic blocks, composite blocks, and hybrid ceramics such as Vita Enamic—with their compositions, mechanical properties, indications, and limitations, including flexural strengths ranging from approximately 160 MPa for glass ceramics to substantially higher values for zirconia. The data-processing stage, comprising direct intraoral and indirect model scanning followed by computer-aided design of a virtual model, is reviewed, along with the two production routes: subtractive milling from prefabricated blocks and additive fabrication by selective laser sintering and 3D printing, which minimizes material waste. Marginal adaptation is discussed as a key determinant of restorative success, with reported clinically tolerable misfit values of 50 to 200 µm and CAD/CAM milling shown to provide superior marginal conformance to conventional techniques. Overall, CAD/CAM workflows offer measurable gains in material quality, accuracy, and efficiency over conventional methods, although optimal outcomes depend on correct material selection, appropriate indication, and proper tooth preparation.

In prosthetic dental treatments, obtaining the negative of the prepared area in the most accurate way directly affects the success of the restoration to be made. Therefore, it is necessary to give importance to the impression material and the impression technique used. Impression materials have undergone changes over the years in order to record the most accurate and sensitive detail. Studies have tried to improve many physical and chemical properties of the impression material. Despite this, it should not be forgotten that there are numerous external factors such as the skill of the clinician, environmental conditions, and storage conditions for the impression to be obtained. Developments in computer-aided design and design (CAD/CAM) technology have significantly increased the use of these systems in dentistry in recent years. In dentistry, many companies in the market aim to minimize the problems that may occur in the laboratory and clinical environment by adding intraoral or extraoral scanners to CAD/CAM systems. The first step of dental CAD-CAM systems is digital scanning with an intraoral or laboratory scanner. This step is followed by the construction phase of restorations with digital design and production devices on the computer. Therefore, the success of these restorations depends largely on the accuracy and precision of the scanning devices. This review will discuss CAD/CAM systems and intraoral scanners and software programs.

Aims: This study aimed to comparatively evaluate the performance of five contemporary large language models (LLMs) on prosthodontics questions of the dentistry specialization examination (DUS) between 2014 and 2024. Methods: A total of 167 prosthodontics questions from the DUS were analyzed. The questions were administered to five different LLMs: ChatGPT-5 (OpenAI Inc., USA), Claude 4 (Anthropic, USA), Gemini 1.5 Pro (Google LLC, USA), DeepSeek-V2 (DeepSeek AI, China), and Perplexity Pro (Perplexity AI, USA). The models’ responses were compared with the official answer keys provided by the Student Selection and Placement Center (OSYM), coded as correct or incorrect, and accuracy percentages were calculated. Statistical analyses included the Friedman test, correlation analysis, and frequency distributions. Subsection analyses were also performed to evaluate model performance across different content areas. Results: DeepSeek-V2 achieved the highest overall accuracy rate (70.06%). Perplexity Pro (53.89%) and Gemini 1.5 Pro (51.50%) demonstrated moderate performance, ChatGPT-5 (49.10%) performed close to human levels, while Claude 4 had the lowest accuracy (32.34%). Subsection analyses revealed high accuracy in standardized knowledge areas such as implantology and temporomandibular joint (TMJ) disorders (66.7-100%), whereas notable decreases were observed in occlusion and morphology questions (9.1-53.9%). Correlation analyses indicated significant relationships between certain models. Conclusion: The findings demonstrate heterogeneous performance of LLMs on DUS prosthodontics questions. While these models may serve as supplementary tools for exam preparation and dental education, their variable accuracy and potential for generating misinformation suggest they should not be used independently. Under expert supervision, LLMs may enhance dental education.

Mekanik özelliklerinin iyi olması, tatmin edici estetik kalitesi, biyolojik stabilitesi ile zirkonya diş hekimliği alanında sıklıkla kullanılan bir materyaldir. Tıbbi ve dental uygulamalarda, özellikle kişiselleştirilmiş üretim yapan cihazlarla entegre edildiğinde, zirkonya kullanılarak istenilen konfigürasyonda üretimler gerçekleştirilebilmektedir. 3D basım tekniği, zirkonya malzemenin kullanımında son yıllarda dikkat çekici ve tartışmalı bir yöntem olarak öne çıkmıştır. Eklemeli sistem (ES) ise, geleneksel sistemlerde elde edilemeyen çok sayıda üretim imkânını beraberinde getirmektedir. Bu derlemede, ES zirkonyanın fiziksel ve adeziv özellikleri, doğruluk, biyouyumluluk ve klinik uygulamaları incelenmiştir. Ayrıca, mevcut kısıtlamalar ile ES zirkonyanın gelişimine yönelik öngörüler ve öneriler sunulmaktadır.

This in vitro study investigates effects of different thicknesses (1 mm, 2 mm, 3 mm) and post-curing durations (20 and 25 min) on the translucency parameters (TP), color differences, and microhardness (HV) of NextDent 3D-printed provisional restorations. Fifty-four disk specimens (10 mm diameter) in three thicknesses (1 mm, 2 mm, 3 mm) were post-cured for 20–25 min, forming six groups (n = 9 per group). Color measurements were taken against white and black backgrounds to calculate TP and color differences. Microhardness was measured using a Vickers hardness tester (100 g load, 10 s). Data were analyzed with two-way ANOVA and pairwise comparisons were performed with LSD post-hoc tests (significance level: 0.05). Thickness significantly influenced TP, with 1 mm specimens showing the highest values (P < .05). Post-curing duration did not significantly affect TP or HV (P > .05). Vickers hardness was higher in 1 mm specimens than thicker samples (P < .05). No significant interaction was found between thickness and post-curing time. Thickness affects translucency and hardness in 3D-printed restorations, while post-curing times of 20 and 25 min had minimal impact. Clinicians should consider thickness based on esthetic and functional needs. Future studies should explore broader post-curing times and additional material properties.

Carbonated drinks are popular beverages among the general population, including dental students. These drinks, such as Coca-Cola, contain high levels of sugar and acidic components, which can contribute to tooth discoloration. This cross-sectional in vivo study was designed to measure the impact of cola consumption on the colour change of the upper anterior six teeth in dentistry students. The objective was to assess colour changes exclusively. This study aimed to evaluate the discoloration on the anterior surface of anterior teeth of dentistry university students after one month of Cola consumption in different consumption groups. A cross-sectional study was conducted among first and second-year dental students (N:64). The upper six anterior teeth, including both canines, of each of the 64 students were measured by spectrophotometer, with three measurements taken to record L, a, b, C, H values per tooth region and the averages recorded. After one month of Coca-Cola consumption, the color measurements of these teeth were repeated. Cola consumption significantly impacted tooth discoloration among dentistry students. Anterior teeth in high-consumption groups showed greater color changes (p < 0.05) across L, a, H, Delta L (ΔL), Delta a (Δa), Delta H (ΔH), Delta E (ΔE) and Delta E00 (ΔE00) values, with marked differences between groups. The findings suggest that Coca-Cola consumption is common among dental students and may be associated with tooth discoloration. This highlights the importance of oral health education and preventive measures among dental students to minimize the risk of tooth discoloration associated with carbonated drink consumption.

This study aims to investigate the bacterial adhesion effect of heat-curing acrylic resins modified with zirconia nanoparticles when interacting with vegan beverages using SEM and FTIR analyses. The bacterial adhesion of heat-cured acrylic resins from Imicryl and Procryla was investigated. The focus was on modified versions of Procryla containing 1 wt% and 3 wt% zirconia nanoparticles. A total of 192 specimens (n = 48 per group) were soaked in four different solutions: distilled water, mineral water, almond milk, and water kefir. Repeated measures ANOVA revealed statistically significant differences (P < .05) in bacterial adhesion among resin groups, beverage types, and immersion times. Specifically, the addition of 1% by weight zirconia to the specimens reduced bacterial adhesion in groups immersed in distilled water (P < .001). Similarly, 3 wt% zirconia reduced adhesion in mineral water (P < .001). However, in groups exposed to other beverages, including mineral water, almond milk, and water kefir, the incorporation of either 1 wt% or 3 wt% zirconia increased bacterial adhesion significantly (P < .001). SEM images corroborated these findings, showing varying patterns of bacterial adhesion on the surfaces of different resin groups under different environmental conditions. The findings indicate the importance of resin composition and beverage type in dictating bacterial interactions on acrylic surfaces. Notably, the addition of zirconia nanoparticles, particularly in Procryla 1Z, demonstrated a significant reduction in bacterial adhesion, highlighting its potential to enhance the antimicrobial properties of acrylic materials. Key points • Zirconia reduces bacterial adhesion in water. • Higher zirconia increases adhesion in vegan beverages. Graphical Abstract

Aim: This study investigates the purposes of social media usage of undergraduate students studying at the faculty of dentistry according to age, daily internet, social media usage, number, and type of social media used. Methods: The study was conducted with 380 undergraduate dental students studying at a university. Data were collected using the questionnaire method. The questionnaire has three parts. The first part has questions to understand people's social and demographic backgrounds, and the second part has questions to evaluate why people use social media. The third section uses the 'Social Media Addiction Scale (SMAS)' to assess social media addiction. The "Social Media Usage Purposes Scale" was used to collect the data. Percentages and frequencies of the scores obtained from the scales regarding various variables were calculated, and t-test and one-way ANOVA tests were performed for variance analyses. Results: The findings indicated no significant correlation between social media addiction and age. However, there was a variation in addiction levels based on the number of social media platforms used and daily internet usage duration. Conclusion: Students using social media for 3-5 hours per day exhibited higher addiction levels than those who used it for shorter or longer durations. How to cite: Görüş Z, Yay Kuşçu HY. Investigation of social media usage and affecting factors among dentistry students. Health Sci Mon 2024;2:e240391. https://doi.org/10.5577/hesmon.e240391