In this study, it was aimed to use a finite element stress analysis method to determine the amount of stress on enamel, dentin, restoration, resin cement and glass ionomer cement in amalgam class II disto-occlusal (DO) cavities by using two different cements with different thicknesses and amalgams with different Young’ s modulus values, respectively. Methods: A three-dimensional tooth model was obtained by scanning an extracted human maxillary first molar with dental tomography. A class II DO cavity including 95-degree cavity margin angles was created. Resin cement (RC) and glass ionomer (GI) cement with different Young’ s modulus measures (RC: 7.7 GPa, GI: 10.8 GPa) were used in amalgam. Different thickness combination groups were simulated: 50 μm, 100 μm and 150 μm. Additionally, amalgams with different Young’ s modulus values were used with the same thickness of different cements (Amalgam Young’s modulus: 35 GPa and 50 GPa). A load of 600 N was delivered to the chewing area. The stress distributions on enamel, dentin, restoration, resin cement and class ionomer cement were then analyzed using finite element analysis. Results: The most stress accumulation was observed in the enamel tissue across all groups where resin cement or glass ionomer cement were used in different thicknesses and where amalgam restorations were used with different Young’s modulus values. The least stress accumulation was observed in the cement itself. Conclusion: According to the results obtained, there was no difference between the two cement types in terms of stress accumulations in the models. However, when the same cements with different thicknesses were evaluated, it was concluded that the presence of both glass ionomer and resin cement with a thickness of 150 μm causes less stress on the restoration surface. Furthermore, when the cements were combined with different thicknesses and with different amalgam Young’ s modulus values, it was concluded that 50 GPa causes less stress on restoration surface.

Amaç: Nazopalatin kanalın (NPK) farklı morfolojik tipleri bulunmaktadır. Bu çalışmanın amacı; NPK morfolojisinin konik ışınlı bilgisayarlı tomografi (KIBT) görüntüleri üzerinden morfolojik olarak değerlendirmektir. Gereç ve Yöntemler: Rastgele seçilen 500 hastanın KIBT görüntüleri retrospektif olarak taranmıştır. Sagittal kesit üzerinde yapılan incelemede hastaların yaş ve cinsiyetlerine göre NPK morfolojik tipleri (silindirik, ağaç dalı, kum saati, huni, muz ve konik) incelenmiştir. Bulgular: Bu çalışmada 269’u kadın, 231’i erkek olmak üzere toplam 500 kişinin KIBT görüntüsünde NPK incelenmiştir. Beş yüz bireyin 127’sinin silindirik (%25.4), 87’sinin huni (%17.4), 72’si kum saati (%14.4), 60’ı (%12) muz şeklinde ve 27’si (% 5.4) ağaç dalı şeklinde NPK formuna sahip olduğu tespit edilmiştir. Yirmi ve altı yaş grubunda yer alan kadınlarda muz tipi görülmezken %36.4 ile en yüksek oranda konik tip NPK izlenmiştir. Üçüncü dekatta ise kadınlarda (%32.5) ve erkeklerde (%27.5) en çok silindirik tip NPK izlenmektedir. Dördüncü dekatta ise kadınlarda %2.94 oran ile muz tipi, erkeklerde ise ağaç dalı ve huni tipi %7.84 ile en az oranda görülmektedir. Beşinci dekatta kadınlarda ve erkeklerde en çok silindirik ve huni tip görülmüş ve ağaç dalı formunda NPK her iki cinsiyette de görülmemiştir. Altıncı dekatta ise huni formda NPK her iki cinsiyette de görülmemiştir. Sonuç: Maksilla anterior bölgede cerrahi operasyonlar öncesinde, anatomik ve morfometrik açıdan NPK tiplerinin KIBT ile incelenmesi önemlidir. Her iki cinsiyette de silindir ve konik tip NPK fazladır.

Bu çalışmada panoramik görüntülerde dişlerin farklı özelliklerine göre pulpa kalsifikasyonları arasındaki ilişki ve pulpa kalsifikasyonlarının sıklığının belirlenmesi amaçlanmaktadır. Gereç ve Yöntem: Necmettin Erbakan Üniversitesi Diş Hekimliği Fakültesi Ağız Diş Çene Radyolojisi Bölümüne Ocak 2020-Eylül 2021 tarihleri arasında başvuran 178 hastanın panoramik görüntüleri çalışmada kullanılmıştır. Dişler diş kuronunun durumuna göre (restorasyonlu, restorasyonlu ve çürüklü, ''çürüklü'', sağlıklı), dişin yer aldığı arkın tarafına göre (sağ, sol) ve dişin bulunduğu çeneye göre (alt, üst) olarak gruplandırılarak pulpa kalsifikasyonunun varlığı değerlendirilmiştir. Elde edilen veriler betimsel istatistikler ve Ki-kare testleri kullanılarak analiz edilmiştir(p<0,05). Bulgular: 660 sağlam dişin 212'sinde (%32,2), 210 çürüklü dişin 90'ında (%42,8), 432 dolgulu dişin 218'inde (%50,5) ve 84 dolgulu ve çürüklü dişin 44'ünde (%52,4) pulpa kalsifikasyonu görülmüştür. Pulpa kalsifikasyonlarının görülmesinde çeneler ve yaş grupları arasında anlamlı bir fark mevcutken cinsiyet ve arkın tarafları arasında anlamlı bir fark gözlenmemiştir. Sonuç: Pulpa kalsifikasyonu incelenen popülasyonda %64,6 oranında, en çok dolgulu dişlerde, en az ise dolgulu ve çürüklü dişlerde izlenmiştir.

Objectives: the aim of this study was to examine the stress distribution of enamel, dentin, and restorative materials in sound first molar teeth with restored cavities with conventional resin composites and bulk–fill composites, as well as to determine their fracture lifetimes by using the three-dimensional finite element stress analysis method. Materials and Methods: an extracted sound number 26 tooth was scanned with a dental tomography device and recorded. Images were obtained as dicom files, and these files were transferred to the Mimics 12.00 program. In this program, different masks were created for each tooth tissue, and the density thresholds were adjusted manually to create a three-dimensional image of the tooth, and these were converted to a STL file. The obtained STL files were transferred to the Geomagic Design X program, and some necessary adjustments, such as smoothing, were made, and STP files were created. Cavity preparation and adhesive material layers were created by transferring STP files to the Solidworks program. Finally, a FE model was created in the ABAQUS program, and stress distributions were analyzed. Results: when the bulk–fill composite and conventional resin composite materials were used in the restoration of the cavity, the structures that were exposed to the most stress as a result of occlusal forces on the tooth were enamel, dentin, restorative material, and adhesive material. When the bulk–fill composite material was used in restoration, while the restorative material had the longest fracture life as a result of stresses, the enamel tissue had the shortest fracture life. When the conventional resin composite material was used as the restorative material, it had the longest fracture life, followed by dentin and enamel. Conclusion: when the bulk–fill composite material was used instead of the conventional resin composite material in the cavity, the stress values on enamel, dentin, and adhesive material increased as a result of occlusal forces, while the amount of stress on the restorative material decreased. In the fracture analysis, when the bulk–fill composite material was used instead of the conventional resin composite material, a decrease in the number of cycles required for the fracture of enamel, dentin, and restorative materials was observed as a result of the forces generated in the oral cavity.

The aim of this study was to investigate the types and thicknesses of adhesive materials used in restorative treatment in dentistry in class I occlusal and class II disto-occlusal cavities and to examine the effects of stress distribution on enamel, dentin, restoration material, and adhesive material using the finite element stress analysis method. A 3-dimensional geometry of the tooth was obtained by scanning the extracted 26 numbered upper molar tooth with dental tomography. The 3D geometry obtained by using the Geomagic Design X 2020.0 software was divided into surfaces, and necessary arrangements were made. With the Solidworks 2013 software, 2 different cavity modeling, class I occlusal and class II disto-occlusal, with a cavity angle of 95 degrees on the 3D model, as well as 10, 30, and 50 micrometers thick, four types of adhesive materials and the modeling of the bulk-fill composite material on it were made. With finite element stress analysis, the stress distribution was analyzed using the Abaqus software. The materials used in the study are included in the simulation as isotropic linear elastic. Periodontal ligament and jawbone were not included in the analysis. A total of 600 N pressure was applied on the models. In our study, it was observed that the amount of stress on the tooth structures changed when the thickness, elastic modulus, and Poisson ratios of the adhesive material were changed. In addition, when all models are examined, it is seen that when the thickness is increased, more stress is placed on the adhesive material compared to the restoration, while when 50-micrometer-thick adhesive material is used, more stress is placed on the restoration compared to the adhesive material.