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.

Finite element analysis has been widely applied in restorative dentistry, but there is limited evidence directly comparing the biomechanical behavior of amalgam and bulk-fill composite resins in standardized cavity designs. This study aimed to evaluate the stress distribution in enamel, dentin, and restorative materials under different cavity configurations and filling materials. A 3D model of a maxillary molar was reconstructed from dental tomography using Geomagic Design X 2020. Four cavity models were created with Solidworks 2013: Class I (occlusal, Group A), Class II disto-occlusal (Group B), Class II mesio-occlusal (Group C), and Class II mesio-occluso-distal (Group D) cavities. Each model was restored with either amalgam or bulk-fill composite and a 600 N occlusal force was applied. Maximum principal stresses were analyzed with ABAQUS software. The highest stress was observed in the bulk-fill composite restoration of the Class II MO cavity (231 Mpa), whereas the lowest stress occurred in amalgam restoration of Class I cavity. Overall, amalgam restorations showed lower stress concentrations than bulk-fill composites, especially in complex cavity designs. These results suggest that cavity configuration and restorative material selection influence stress distribution and may impact the long-term biomechanical stability of restored teeth.

Using a three-dimensional finite element analysis, this study aimed to evaluate the effect of different cements’ thicknesses and Poisson’s ratios on the stress distribution in enamel, dentin, restoration, and resin cement in a computer-aided design of a class II disto-occlusal cavity. Dental tomography was used to scan the maxillary first molar, creating a three-dimensional tooth model. A cavity was created with a 95 degree cavity edge angle. Resin cement with varying Poisson’s ratios (V1: 0.35 and V2: 0.24) was used under the amalgam. The simulated groups’ thicknesses ranged from 50 µm to 150 µm. A load of 600 N was applied to the chewing area. The finite element method was used to assess the stress distribution in the enamel, dentin, restorations, and resin cement. The stress in the restoration increased with the use of a 100 µm resin cement thickness and decreased with the use of a 150 µm resin cement thickness. For the V1 and V2 groups, the cement thickness with the maximum stress value for the enamel and dentin was 150 µm, while the cement thickness with the lowest stress value was 50 µm. The greatest stress values for V1 and V2 were obtained at a 150 µm cement thickness, while the lowest stress values were observed at a 100 µm cement thickness. Using resin cement with a low Poisson’s ratio under amalgam may reduce stress on enamel and restorations.

Patients with physical and/or mental disabilities exhibit higher caries activity and more treatment needs compared with the general population. Thus, the number of patients awaiting dental treatment under general anesthesia (GA) is far from negligible. Factors such as disabilities, presence of comorbidities, underlying medical conditions, and potential drug interactions render these patients a high-risk group for GA. Consequently, meticulous planning is essential when scheduling dental treatment under GA. The objective of the present research was to gather the opinions of anesthesiologists and dentists regarding the prompt treatment of dental patients requiring GA in institutions that offer optimal conditions for patient safety. Data were collected using a 28-item questionnaire developed by the researchers based on a literature review and interviews with both dentists and anesthesiologists involved in dental procedures under GA. The survey was administered online via Google Forms. Nearly all respondents (95.0%) believed that having an in-house operating room would increase their work efficiency and such a facility would meet their expectations. When asked why having an in-house operating room would enhance efficiency, the most common reasons cited were the ability to schedule more surgery days, better communication from working with the same anesthesia team, and the elimination of time lost due to transfers between hospitals. Anesthesiologists stated that the most frequently encountered issues when admitting patients in operating rooms within the faculty of dentistry were the absence of another anesthesiologist in emergencies (46.7%) and difficulty in reaching a consultant physician when needed (20.0%). Furthermore, 79.2% of anesthesiologists expressed that they would not prefer to work in an operating room dedicated solely to dental patients. As a result, dentists and anesthesiologists, the two most important members of the team performing dental treatments within GA, prefer to perform the procedures within their own institutions. Considering the high number of patients waiting for dental treatment under GA, the establishment of operating rooms within dentistry can make a positive contribution to the health system by eliminating the hesitations of anesthesiologists.

Aim: This study examines dental faculty students' ethical sensitivity and attitudes toward ethical decision-making in healthcare. Despite frequent ethical dilemmas among dentists, there's limited research on dental students' experiences. This study aims to fill this gap by assessing dental students’ ethical sensitivity. Methods: Conducted between June and July 2021 with 436 voluntary participants from 1st to 5th grade students at a Faculty of Dentistry. Data were collected using a sociodemographic form and "Moral Sensitivity Questionnaire" (MSQ), 30-item tool with six sub-dimensions: autonomy, benefit, holistic approach, conflict, implementation, and orientation. Reliability analysis used Cronbach's Alpha, statistical analyses were performed. Results: Study found that 61.9% of participants were women, with an average age of 21.64 years. The overall reliability value of the MSQ scale was 0.920. The highest agreement among survey items was with "I often experience contradictions about how to approach the patient" (4.49±1.69). Significant differences were found in autonomy and application sub-dimensions based on students' grade levels (p=0.002). There was no significant gender difference in moral sensitivity (p>0.05), and no significant correlation was found between age and moral sensitivity. Conclusion: Findings highlight the importance of developing and protecting dental students' moral and ethical sensitivities for their professional success and public health. They underscore the need for enhanced ethics education in dental curricula and stronger hospital ethics committees to support healthcare professionals in ethical decision-making. This research offers valuable insights into the ethical challenges faced by dental students and emphasizes the necessity for further studies in this area.

Background: The deep margin elevation (DME) technique provides advantages for root canal treatment, but the impact of applied irrigation protocols on bonding for subsequent restorations is a significant concern. The aim of this in vitro study was to test the bond strength of a flowable resin material used in DME restorations after composite restorations were exposed to different irrigation protocols. Methods: Standard composite samples (G-aenial^® Universal Injectable) were divided into nine groups according to irrigation protocols. Untreated composite sample were used as control. The group A were kept in 5.25% sodium hypochlorite (NaOCl) and the group B were kept in 3.5% chlorine dioxide (ClO₂) for 30 min. Then, the following treatment protocols were applied to the subgroups, respectively. Group1A/B: 17%EDTA + 5.25%NaOCl + Distilled Water + 2%CHX, Group2A/B: 18%HEDP + 5.25%NaOCl + Distilled Water + 2%CHX, Group3A/B: 17%EDTA + 3.5%ClO₂ + Distilled Water + 2%CHX, Group4A/B: 18%HEDP + 3.5%ClO₂ + Distilled Water + 2%CHX. After irrigation procedures, samples were washed with distilled water and sandblasted. G-Premio Bond and composite restorations (G–aenial^® A’CHORD) were applied. The samples were then cut perpendicular to the interface with an IsoMet^® low speed diamond saw under water. For the microtensile bond strength test, rectangular sticks with an average cross-sectional area of ∼1 mm² will be obtained. The first section with 1-mm thickness was excluded to prevent its possible confounding effect on the results. Three sections were obtained of each sample (n = 15) and tested for microtensile bond strength. The analysis of the data collected in accordance with the purpose of the study was performed with One-way ANOVA (n = 15). For multiple comparisons between groups, it was evaluated with Tukey HSD test. Results: Groups A1 and A2, immersed in NaOCl for 30 min, showed statistically significantly lower bond strength compared to Group B3, immersed in ClO₂ for 30 min, and the control group (P < 0.05). The use of ClO₂ irrigation is recommended due to its positive effects on bond strength. Conclusion: Prolonged NaOCl irrigation may adversely affect the bond strength of flowable composites used for deep margin elevation.