Resistance fracture of minimally prepared endocrowns made by three types of restorative materials: a 3D finite element analysis

A thin endocrown restoration was often applied in endodontically treated teeth with vertical bite height loss or inadequate clinical crown length. A model of mandibular molars made by endocrown restoration with 1 mm thickness and 2 mm depth of pulp chamber was constructed and imported into FEA ANSYS v18.0 software. The three CAD/CAM materials, feldspathic (Mark2), lithium disilicate (EMAX), and lava ultimate (LU), were assigned, and the five load indenters were loaded on the full occlusal (FO), occlusal center (OC), central fossa (CF), buccal groove (BG), and mesiobuccal cusp (MC) of restoration in the model. The MinPS and MaxPS of the thin endocrown were significantly higher than those of tooth tissue in five types of loads except for the LU endocrown loaded in the FO group. The smaller the contact surface of the load was, the higher MaxPS and MinPS were. MaxPS and MinPS of the MC were the highest, followed by the BG and CF in the restoration. In the stress distribution of tooth tissue, MaxPS in the LU endocrown accumulated at the external edge of enamel and was significantly higher than MaxPS in Mark2 and EMAX endocrown concentrated on the chamber wall of dentin under OC, CF and BG loads. Within the limitations of this FEA study, the LU endocrown transferred more stress to tooth tissue than Mark2 and EMAX, and the maximum principal stress on endocrown restoration and tooth tissue at the mesiobuccal cusp load was higher than that at the central fossa and buccal groove load.

Resistance Fracture of Minimally Prepared Endocrowns Made By Three Types of Restorative Materials: A 3D Finite Element Analysis

A thin endocrown restoration was often applied in endodontically treated teeth with vertical bite height loss or inadequate clinical crown length. A model of mandibular molars made by endocrown restoration with 1 mm thickness and 2 mm depth of pulp chamber was constructed and imported into FEA ANSYS v18.0 software. The three CAD/CAM materials, feldspathic (Mark2), lithium disilicate (EMAX) and lava ultimate (LU), were assigned, and the five load indenters were loaded on the full occlusal (FO), occlusal center (OC), central fossa (CF), buccal groove (BG) and mesiobuccal cusp (MC) of restoration in the model. The MinPS and MaxPS of the thin endocrown were significantly higher than those of tooth tissue in five types of loads except for the LU endocrown loaded in the FO group. The smaller the contact surface of the load was, the higher MaxPS and MinPS were. MaxPS and MinPS of the MC were the highest, followed by the BG and CF in the restoration. In the stress distribution of tooth tissue, MaxPS in the LU endocrown accumulated at the external edge of enamel and was significantly higher than MaxPS in Mark2 and EMAX endocrown concentrated on the chamber wall of dentin under OC, CF and BG loads. Within the limitations of this FEA study, the LU endocrown transferred more stress to tooth tissue than Mark2 and EMAX, and the maximum principal stress on endocrown restoration and tooth tissue at the mesiobuccal cusp load was higher than that at the central fossa and buccal groove load.

Ultrasonic Image Diagnosis of Liver and Spleen Injury Based on a Double-Channel Convolutional Neural Network

Automatic and accurate diagnosis of liver and spleen injury in ultrasonic images is of great significance for the development of automatic clinical diagnosis. In order to realize more accurate ultrasonic image diagnosis of liver and spleen injury, an algorithm of ultrasonic image classification diagnosis of liver and spleen injury based on double-channel convolutional neural network was proposed. Firstly, the anisotropic diffusion denoising model is used to realize data preprocessing of ultrasonic images of the liver and spleen to improve the image quality of ultrasonic images. Secondly, the external edge of the lesion location was detected to obtain the characteristics of the external edge. Then, the rotation invariant local binary mode feature of the extracted image is taken as the inner texture feature of the image. Finally, the external edge feature and internal texture feature are used as two input channels of the convolutional neural network, respectively, to classify and identify ultrasonic images of liver and spleen injury. The experimental results show that the proposed method diagnoses liver and spleen injury more accurately.

Anatomy of Rouviere’s Sulcus and Its Association with Complication of Laparoscopic Cholecystectomy

Background and Objective(s). Rouviere’s sulcus (RS) is an important anatomical landmark. The aim of this study was to find the distribution of anatomical characteristics of RS seen during laparoscopic cholecystectomy in the population of our part of the world and its association with complications. Methods. This is a prospective observational study involving patients of age ≥16 years who underwent laparoscopic cholecystectomy for uncomplicated gall stone at BPKIHS between May and July 2019. Result. 230 cases were analyzed, and RS was present in 90.4%. Open sulcus type was the commonest (54%), followed by scar type (22.9%), closed sulcus type (12.5%), and slit type (10.6%), respectively. In 59.1% of cases, it was oblique to the anterior, inferior, and external edge of the liver, while in the remaining cases, it was transverse. The mean ± SD values for operative time and duration of hospital stay in the RS visible and the RS not visible groups were 29.16 ± 8.736 and 42.9 ± 23.646 minutes, and 1.26 ± 0.440 and 1.90 ± 0.910 days, respectively (p value ≤0.001). One minor complication occurred in each group: RS initially visible group and RS visible on the adhesion release group, while 3 minor complications occurred in the RS not visible group. Only one major complication occurred in the RS not visible group. Conclusion. Identification of RS by operating surgeons is a predictor of safe laparoscopic cholecystectomy.

Stability of boundary layer flow based on energy gradient theory

The flow of the laminar boundary layer on a flat plate is studied with the simulation of Navier–Stokes equations. The mechanisms of flow instability at external edge of the boundary layer and near the wall are analyzed using the energy gradient theory. The simulation results show that there is an overshoot on the velocity profile at the external edge of the boundary layer. At this overshoot, the energy gradient function is very large which results in instability according to the energy gradient theory. It is found that the transverse gradient of the total mechanical energy is responsible for the instability at the external edge of the boundary layer, which induces the entrainment of external flow into the boundary layer. Within the boundary layer, there is a maximum of the energy gradient function near the wall, which leads to intensive flow instability near the wall and contributes to the generation of turbulence.

Evaluation of Classical Models for Thermal and Moisture Transport in Stone Walls of Historical Buildings

This paper concerns the evaluation and the validation of a heat and moisture transfer models in stone walls using in situ measurements on an instrumented wall. Firstly, a pure thermal (respectively moisture) diffusion problems are considerate, then this problem was combined with convection on the external edge of model. It is found that, despite of an uncoupled approach, the nonlinear thermal diffusive model performs quite well and reproduces perfectly the measured temperatures. It is the same for the convective-diffusive thermal problem, where the temperature on the surface wall is also reproduced quite well. An improvement of this second type problem results could be expected by taking into account the radiation. Otherwise, the both cases of moisture transfer problem (purely diffusive or diffusive-convective problem) are ill-simulated by the Kunzel’s model.

Biostratigraphical and sedimentological study of an Upper Cretaceous succession in the Sami area (central area of Kefallinia, W. Greece)

On the island of Kefallinia, which lies at the external edge of the Hellenides fold and thrust system, appear the Paxi and the Ionian Zones. In this study, an Upper Cretaceous carbonate succession, which is a part of the Paxi Zone, cropping out near the area of Sami (central area of Kefallinia), is discussed in detail with regard to its depositional facies, microfacies, biostratigraphy and palaeoenviroments. Detailed sedimentological and palaeontological investigations have been carried out on seven sections and petrographic analysis of thin-sections that led to the recognition of a number of microfacies types grouped into four facies zones. There was recorded a supratidal- intertidal (restricted)-intertidal (open lagoon)- subtidal (or shallow subtidal) vertical transition. Supratidal facies are characterized by fenestral and peloidal wackestone / packstone, intertidal (restricted) facies are represented by bioclastic wackestone and bindstone, whereas intertidal (open lagoon) facies are indicated by bioclastic packstone. Finally subtidal facies are dominated by bioclastic floatstone and grainstone. Benthic foraminifera are especially abundant and along with calcareous algae are the most important fossils used for age determination. The benthic foraminiferal genera that were identified (Cuneolina sp., Quinqueloculina sp., Nezzazata sp., Pseudonummoloculina sp., Dicyclina sp.), in addition with the observed calcareous algae, rudist and gastropods provide significant data for the depositional environments and the paleoecology of the Paxi Zone during the Upper Cretaceous.

The Oscar Ramirez Procedure, a Solution for Treating Incisional Hernias with Big Abdominal Wall Defect

Background: Incisional hernias are important complications of abdominal surgery. Normally they are followed by the growth of the hernia sac and an increase of the abdominal wall defect with loss of domain of the herniated organs. Case report: We report a case of a 51 year old female, admitted in the 1st Surgical Clinic of the County Emergency Clinical Hospital of Tîrgu Mureș with a large median reducible incisional hernia and a wall defect of 10/12 cm. The abdominoplasty was performed using the Oscar Ramirez technique, which consists of a longitudinal incision along the aponeurosis of the external oblique muscle, at approximately 1-2 cm from the external edge of the rectus abdominis. This procedure allows the abdominal wall closure. This case is part of a lot of 4 patients who received this treatment using the aforementioned procedure in the past 2 months. Postoperative recovery was favorable, bowel movements were present on the second day after the surgery, the subcutaneous drains were shortened on the fifth day and removed on the sixth. There were no immediate postoperative complications or up to a month after the surgery. The patient was discharged on the seventh day. Conclusions: This technique can be used alone in case of large abdominal wall defects, or prequeling an on-lay mesh procedure addressed to a weak abdominal wall, case in which the functional result is superior to a substitutional mesh.

Cumulative Effect of Pressing and Drying on Stress Generation within a Green Ceramic Compact

The internal stress field induced by uniaxial pressing and subsequent convective drying of a green ceramic powder was simulated by the finite element method. A density dependent elastoplastic constitutive law was used for the mechanical modeling of the compaction. A diffusive water transfer equation and a purely elastic behavior with imposed hydrostrain involving shrinkage were applied for the modeling of the drying process. The key material properties (hydrodiffusivity, hydrocontraction coefficient, Young’s modulus, Poisson’s ratio, and yield surface parameters) had been experimentally measured and introduced as functions of material density and water content. If residual stresses due to the compaction operation were taken into account, the maximum value of the tensile stress at the top external edge of the wheel and at the beginning of the drying process was two times higher than for a stress free green ceramic compact. Beyond the residual stress onset, the compaction operation induced density heterogeneities which had important consequences on the mechanical behavior of the compact.