Effect of finish line design on stress distribution in bilayer and monolithic zirconia crowns: a three‐dimensional finite element analysis study

This study evaluated the influence of different finish line designs and abutment materials on the stress distribution of bilayer and monolithic zirconia crowns using three‐dimensional finite element analysis (FEA). Three‐dimensional models of two types of zirconia premolars – a yttria‐stabilized zirconia framework with veneering ceramic and a monolithic zirconia ceramic – were used in the analysis. Cylindrical models with the finish line design of the crown abutments were prepared with three types of margin curvature radius (CR): CR = 0 (CR0; shoulder margin), CR = 0.5 (CR0.5; rounded shoulder margin), and CR = 1.0 (CR1.0; deep chamfer margin). Two abutment materials (dentin and brass) were analyzed. In the FEA model, 1 N was loaded perpendicular to the occlusal surface at the center of the crown, and linear static analysis was performed. For all crowns, stress was localized to the occlusal loading area as well as to the axial walls of the proximal region. The lowest maximum principal stress values were observed when the dentin abutment with CR0.5 was used under a monolithic zirconia crown. These results suggest that the rounded shoulder margin and deep chamfer margin, in combination with a monolithic zirconia crown, potentially have optimal geometry to minimize occlusal stress.     

Diffusion tensor imaging of normal brain development

Diffusion tensor imaging (DTI) is an MRI technique that can measure the macroscopic structural organization in brain tissues. DTI has been shown to provide information complementary to relaxation-based MRI about the changes in the brain’s microstructure. In the pediatric population, DTI enables quantitative observation of the maturation process of white matter structures. Its ability to delineate various brain structures during developmental stages makes it an effective tool with which to characterize both the normal and abnormal anatomy of the developing brain. This review will highlight the advantages, as well as the common technical pitfalls of pediatric DTI. In addition, image quantification strategies for various DTI-derived parameters and the normal brain developmental changes associated with these parameters are discussed.     

Multi-Center Analysis of Liver Transplantation for Combined Hepatocellular Carcinoma-Cholangiocarcinoma Liver Tumors

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Imbalance of coagulation and fibrinolysis can predict vascular access failure in patients on hemodialysis after vascular access intervention

Objective

For patients with end-stage renal disease on hemodialysis, the durability of vascular access (VA) is still far from optimal, and access survival after intervention for access failure is an important aspect. Procoagulant status is a leading cause of access failure. Coagulation-fibrinolysis imbalance can occur in hemodialyzed patients, but the influence of the imbalance has not been fully elucidated.

Endoscopic submucosal resection with an endoscopic variceal ligation device for the treatment of rectal neuroendocrine tumors

Background

Endoscopic resection is recommended for rectal neuroendocrine tumors <?1 cm in diameter; the three techniques (mucosal resection, submucosal dissection, and mucosal resection with variceal ligation device) of endoscopic resection of neuroendocrine tumor were reported; however, the optimal endoscopic technique remains unclear.

Purpose

We compared the efficacy and safety of three endoscopic rectal neuroendocrine tumor resection methods.

Methods

We retrospectively enrolled 52 patients with rectal neuroendocrine tumors treated by endoscopy at Aichi Medical University Hospital and Nagoya City University Hospital between May 2003 and June 2017. We compared clinical outcomes in three groups based on the endoscopic treatment method.

Results

Fifty-two patients underwent endoscopic rectal neuroendocrine tumor treatment (mucosal resection, 14; submucosal dissection, 19; mucosal resection with an endoscopic variceal ligation device, 19). In the endoscopic mucosal resection, submucosal dissection, and mucosal resection with variceal ligation device groups, R0 resection occurred in 50.0, 94.7, and 89.5%, respectively (mucosal resection vs. mucosal resection with variceal ligation device, p <?0.05; mucosal resection vs. submucosal dissection, p <?0.01), while the median procedure times were 6.5, 43, and 6.0 min, respectively (submucosal dissection vs. mucosal resection with variceal ligation device procedure times, p?<?0.01; mucosal resection vs. submucosal resection procedure times, p <?0.01). Postoperative bleeding occurred after endoscopic mucosal resection (1/14) and endoscopic submucosal dissection (4/19), but not after endoscopic mucosal resection with a ligation device.

Conclusion

Endoscopic mucosal resection with an endoscopic variceal ligation device was a safe, effective treatment for rectal neuroendocrine tumors.