Objectives The aim of the study was to analyze the occurrence of stress on teeth with abfraction lesions restored with six different restorative materials, and by introducing the tensile strength parameters to calculate the safety factor of the material under the load (ratio between the strength of the material and the maximum stress). Materials and Methods Three-dimensional models of the mandibular premolar are created from a microcomputed tomography images. An abfraction lesion is modeled on the tooth. The stress of the dental tissues and six restorative materials under functional and nonfunctional occlusal loading of 200 (N) are analyzed by finite element method. Statistical Analysis CTAn program 1.10 and ANSYS Workbench (version 14.0) were used for analysis. Results are presented in von Mises stress. Results Oblique loads caused ≈ four times higher stress in restorative materials than the axial ones. It is noticeable that high values of von Mises stress are measured at the bottom of the sharp lesion, even up to 240 MPa, that are significantly reduced after the restoration. The highest stresses at the restorative material are present at the lower (gingival) margin of the restoration. The highest stresses under both types of loads are measured in nanohybrid composite (Tetric EvoCeram, Ivoclar Vivadent). The lowest values of the stress are measured in the flowable composite (Tetric Flow, Ivoclar Vivadent), but at the same time, the highest value of the stress is measured in the surrounding dental tissues on the tooth restored with the flowable composite. The microhybrid composite (Herculite XR, Kerr), with the highest safety factor, is the material that best withstands the stresses it is exposed to. The obtained safety factor did not exceed the critical limit, except for the glass ionomer cement, with the safety factor lower than 1. Conclusion The type of tooth loading has the greatest influence on the intensity of stress. The value of the obtained stresses in the restorative material and dental tissues differ due to the different mechanical properties of the materials. Restoration of noncarious lesions significantly reduces extremely high stress values at their bottom.

Introduction: Axial-loaded magnetic resonance imaging (MRI), which can simulate an upright position of the patient may cause a significant reduction of the dural sac cross-sectional area (DCSA) compared with standard MRI, thus providing valuable information in the assessment of the lumbar spinal canal. The purpose of this study was to investigate excessiveness of the change in DCSA and depth of lateral recesses (DLRs) before and after axial-loaded imaging in relation to body mass index (BMI) of the subjects.Methods: Twenty patients were scanned to evaluate DCSA and DLR at three consecutive lumbar spine intervertebral disc levels (L3/4, L4/5, and L5/S1) on conventional-recumbent MRI, and after axial loading were applied.Results: Axial-loaded MRI demonstrates a significant difference of DSCA in comparison to conventional MRI. Furthermore, results show a significant correlation between the DCSA and BMI on level L3/L4, both before and after axial loading MRI. With axial loading, there is a reduction of DSCA of 12.2%, 12.1%, and 2.1% at the levels L3/L4, L4/L5, and L5/S1, respectively. After axial loading has been applied, the depth of the neural foramen has been reduced by an average of 10.1%.Conclusion: Axial-loaded MRI reduces DCSA and DLRs in comparison to standard MRI. Information obtained in this way may be useful to explain the patient’s symptomatology and may provide an additional insight that can influence the treatment decision plan accordingly.

Background: The development of novel medical imaging technologies and treatment procedures hinges on the availability of accurate and versatile phantoms. This paper presents a cost-effective approach for creating anthropomorphic abdominal phantoms. Methods: This study proposes a cost-effective method using 3D printing and readily available materials (beeswax, plaster, and epoxy resin) to create high-fidelity anthropomorphic abdominal phantoms. The three-dimensionally printed phantoms exhibited X-ray attenuation properties closely matching those of human tissues, with measured Hounsfield unit (HU) values of −115.41 ± 20.29 HU for fat, 65.61 ± 18.06 HU for muscle, and 510 ± 131.2 HU for bone. These values were compared against patient images and a commercially available phantom, and no statistically significant difference was observed in fat tissue simulation (p = 0.428). Differences were observed for muscle and bone tissues, in which the 3D-printed phantom demonstrated higher HU values compared with patient images (p < 0.001). The 3D-printed phantom’s bone simulation was statistically like that of the commercially available phantom (p = 0.063). Conclusion: This method offers a cost-effective, accessible, and customizable alternative for abdominal phantoms. This innovation has the potential to accelerate advancements in abdominal imaging research, leading to improved diagnostic tools and treatment options for patients. These phantoms could be used to develop and test new imaging techniques with high accuracy.

Introduction: The main purpose of root canal filling materials is to provide an apical sealing that prevents the movement of bacteria and the diffusion of their metabolic products from the root canal system to periapical tissue. The aim of this study was to evaluate the apical sealing ability of mineral trioxide aggregate’s (MTA), epoxy resin, and zinc oxide eugenol- based sealer with single cone obturation techniques using the dye extraction leakage method. Methods: Seventy-five extracted human single-rooted teeth were instrumented using the crown-down technique with the Mtwo rotary file system to file 25/6. The teeth were randomly divided into five experimental groups (n = 15); Group 1 obturated with AH plus, Group 2 obturated with MTA BIOSEAL, Group 3 obturated with Endoseal, Group 4 positive control (POS CTRL) root canals are processed but not obturated, and negative control- apex of teeth completely covered with nail varnish, canals are not treated or obturated. In the first three groups, the single cone obturation technique with gutta-percha 25/6 was used. Apical microleakage was assessed with the dye extraction method, where the absorbance of 2% methylene blue was measured using a spectrophotometer. Results: The mean dye concentration values were MTA 22.79, AH plus 31.16, Endoseal 36.67, POS CTRL 280.15, negative control 9.01. Analysis of variance and pairwise comparisons indicated a significant difference in apical microleakage between the investigated groups (F = 3448, p < 0.001). The MTA BIOSEAL showed significantly less apical microleakage than the AH plus and Endoseal. The AH plus showed less apical microleakage than the Endoseal, although there was no significant difference between these two sealers. Conclusion: With the limitation of the study, it was concluded that MTA sealers show statistically less apical leakage than AH Plus and Endoseal.