Purpose: This study evaluated biomechanical behavior of endocrown and post-core restorations produced from computer aided design/computer aided manufacturing (CAD/CAM) and traditional materials in severely damaged teeth that lack a ferrule and assessed the associated failure risk of resin cement.Methods: A phantom maxillary central incisor and mandibular second premolar were trimmed 1 mm coronally to the cemento-enamel junction, the root canals were enlarged, and the teeth were scanned. Data were transferred to a solid modeling software. Twenty-two models were constructed, including endocrowns (hybrid ceramic, lithium disilicate, and polyetheretherketone [PEEK]) and post-cores (glass-fiber post/composite core; glass-fiber single-piece post-core; PEEK single-piece post-core; gold single-piece post-core). Hybrid ceramic and lithium disilicate crowns were modeled on the post-cores. Loads of 100 N for the central incisor and 300 N for the premolar were applied in a 45° oblique direction. von Mises stresses were analyzed on both root dentin and restorations, and the failure risks for the resin cement were calculated.Results: The highest stresses were found at the roots of the PEEK endocrown (37.6 MPa) for the central incisor and of the lithium disilicate endocrown for the premolar (40.0 MPa) among endocrown groups. PEEK endocrowns had the lowest stress within the restoration and presented a higher risk of cement failure. The glass-fiber post/composite core groups demonstrated the highest adhesive and cohesive failure risks for post cement.Conclusions: For the central incisor and mandibular premolar, lithium disilicate and PEEK endocrowns, respectively, generated less stress at the root. However, PEEK endocrowns had a higher risk of cement failure.

Amaç: Bruksizm ile ilgili bilgi kaynağı olarak YouTube™ videolarının içeriğinin ve kalitelerinin değerlendirilmesidir. Gereç ve Yöntem: YouTube™ videolarında “diş sıkma, bruksizm” kelimeleri ile Türkçe videolarda arama yapıldı ve ilk sırada yer alan videoların URL’leri kaydedilerek iki araştırmacı tarafından tüm videolar incelendi. Videolara ait tanımlayıcı istatistikler kaydedildi ve verilerin minimum, maksimum, ortalama, standart sapması hesaplandı. Elde edilen değerler, istatistiksel olarak incelendi ve sürekli değişkenler Kruskal-Wallis testi ile analiz edildi (p<0.05). Bulgular: Toplam 250 video değerlendirmeye alındı. Bu videolardan değerlendirme kriterlerine uyan 68 video çalışmaya dahil edildi. Değerlendirmeyi yapan iki gözlemci arasında istatistiksel olarak anlamlı seviyede yeterli uyum vardı (Kappa=0.754, p0.05). Sonuç: Bruksizm ile ilgili YouTube™’da yer alan videoların çoğu az yararlıdır. Alanında uzman hekimler ve akademisyenler, YouTube™’a daha yararlı ve bilgilendirici videolar ile katkı sağlayabilirler, bireylerin doğru bilgiye ulaşmasına ve toplum sağlığına faydalı olabilirler.

Artificial intelligence (AI) chatbots are increasingly used in healthcare to provide health-related information and answer patient questions. However, their reliability in specialized dental fields such as restorative dentistry remains insufficiently evaluated. This study aimed to evaluate and compare the accuracy and consistency of responses generated by five artificial intelligence chatbot systems-ChatGPT-3.5 and ChatGPT-4 (OpenAI), Bing Chat (Microsoft), Gemini (Google), and Claude-Instant (Anthropic)-regarding dental bleaching. Fifteen frequently asked questions about dental bleaching, identified by restorative dentistry specialists, were categorized as undergraduate-or specialist-level questions. All questions were submitted to five artificial intelligence chatbots in both Turkish and English. Each question was asked three times per day over three consecutive days using standardized prompts. Responses were independently evaluated by two experts using a five-point Likert scale, and mean scores were calculated. A three-way ANOVA was conducted to assess the effects of chatbot type, knowledge level, and question language on response accuracy. Inter-rater agreement between evaluators was assessed using Cohen's kappa coefficient. Statistical significance was set at p < 0.05. Chatbot type had a significant effect on response accuracy (p < 0.001, η² = 0.405). ChatGPT-4 showed the highest accuracy, followed by Claude-Instant and GPT-3.5, whereas Gemini and especially Bing Chat demonstrated significantly lower performance (p < 0.001). Question language and knowledge level showed no significant main effects (p > 0.05). Significant interactions were observed between chatbot type and knowledge level and between chatbot type and language (p < 0.001). No significant differences were observed across days or time periods (p > 0.05). The accuracy of chatbot-generated information regarding dental bleaching depends strongly on the specific AI model used. Advanced large language models, particularly ChatGPT-4, generate more accurate and consistent responses than other evaluated systems. AI chatbots should therefore not be considered interchangeable sources of clinical information, and their outputs should be interpreted cautiously and verified with professional guidance. These findings highlight the importance of critically evaluating AI-generated health information and emphasize that chatbot responses should not replace professional clinical consultation.

Amaç: Bu çalışmanın amacı üç farklı ışık cihazı ile polimerize edilen bulk-fill kompozitlerde, kalınlığın artışının mikrosertlik üzerine etkisinin incelenmesidir. Gereç ve Yöntemler:İki farklı bulk-fill kompozit (Tetric Evo Ceram Bulk Fill, X-trafil) ve bir adet akışkan bulk-fill kompozit (SDR) kullanıldı. Kompozitler 1mm derinliğinde 5 mm çapında, dört metal kalıba yerleştirilerek iki farklı LED ışık cihazı (Blue Phase and Valo) ve bir adet halojen ışık cihazı (Hilux) ile polimerize edildi. Örnekler 24 saat 37°C’de %100 nemli ortamda bekletildi. Vickers sertlik ölçümleri 5 saniye 100 gr kuvvet uygulanarak yapıldı. Her örneğin hem üst hem de alt yüzeyinden 3 ölçüm yapıldı. Elde edilen veriler 0.05 istatistik seviyede analiz edildi. Bulgular:Hem üst hemde alt yüzeylerde bütün ışık cihazları ile polimerize edilen X-tra fill diğer gruplara göre belirgin düzeyde yüksek sertlik değerleri göstermiştir (p0.05). Sadece SDR, Blue phase ile polimerize edildiğinde diğer ışık cihazlarına göre daha düşük sertik değerleri göstermiştir (p<0.05). Kompozit tabakaları ile sertlik arasındaki ilişki incelendiğinde, halojen ile polimerize edilen Tetric Evo Ceram ve X-trafill kompozitlerin 1. ve 4. mm’de sertlikte belirgin düzeyde fark gözlenmiştir (p0.05).Sonuçlar: Kompozitlerin sertlikleri materyal, ışık cihazı ve derinliğe bağlı olarak değişmektedirAnahtar Kelimeler: kompozit rezin, dental ışık cihazları, sertlik testi

Background/aim: This study aimed to evaluate the relationship between the impaction level and angulation of third molars and the incidence of caries in the adjacent second molars. Materials and methods: A total of 690 panoramic radiographs obtained from patients at Ankara Yıldırım Beyazıt University between May 2022 and January 2024 were retrospectively analyzed. Third molars were classified based on their eruption status using the Pell and Gregory classification (levels A, B, and C), and angulation (mesioangular, distoangular, vertical, horizontal, and inverted). The presence of caries in adjacent second molars was assessed using the international caries detection and assessment system/international caries classification and management system. The association between third molar position and the presence of caries in second molars was statistically evaluated. Results: Among the 1164 third molars assessed, 52.9% were located in the mandible, and 75.2% were in a vertical position. Carious lesions were identified in 22.3% of third molars. Adjacent mandibular second molars had caries in 53.2% of cases, compared to 35.6% in the maxilla. According to the Pell and Gregory classification, class I, level A mandibular third molars were associated with the highest incidence of caries in adjacent second molars (159 out of 616). Furthermore, when only impacted teeth were considered, mesioangular impactions were associated with the highest prevalence of caries, observed in 41.1% of cases (51 out of 123). Conclusion: The findings indicate that the position and angulation of third molars play an important role in the risk of caries development in adjacent second molars. In the mandible, level A third molars in vertical (65.2%) and mesioangular (41.1%) positions had the greatest risk for caries development in adjacent second molars, whereas in the maxilla, the highest risk was found in vertical (47.3%) and mesioangular (25.7%) impactions. These results underscore the importance of early clinical evaluation and the implementation of preventive strategies to minimize caries risk in second molars associated with impacted third molars.