Endoscopic ultrasound-guided biliary drainage for distal malignant biliary obstruction: a prospective 3-year multicenter Egyptian study.

Background/Aim: Malignant biliary obstruction (MBO) is often diagnosed at late stages with mostly unresectable lesions. Recently, EUS-guided biliary drainage (EUS-BD) has gained wide acceptance and appears to be a feasible and safe backup option after ERCP failure in such patients. Herein, we aimed to represent a 3-year multi-center Egyptian experience in the application of this challenging procedure for distal MBO as a salvage technique after failed ERCP. Patients and methods: This was a prospective multi-center study of patients underwent EUS-BD for distal MBO in the duration between December 2018 and December 2021, after ERCP failure. Results: Ninety-one patients (59 males, median age: 61 years) were included in the study. EUS-guided extrahepatic approach including choledocho-duodenostomy (CDS) was done for 48 patients (52.8%), followed by choledecho-antrostomy (CAS) in 4 patients (4.4%). The intrahepatic approach included hepaticogastrostomy (HGS) for 35 patients (38.5%) and antegrade stenting (AG) stenting in 2 patients (2.2%), while Rendezvous (RV) approach was performed in 2 patients (2.2%). Technical and Clinical success were achieved in the majority of cases; 93.4% and 94.1% respectively. Adverse events occurred in 13.2% of patients which were mostly mild (8.2%) to moderate (2.4%). Only one patient died within 48h after the procedure with progression of preceding sepsis and organ failure. Conclusion: EUS-BD is a feasible option, even in developing countries, after a failed ERCP, and it is a relatively safe option in patients with MBO once experienced team and resources were present. Majority of cases in our study have achieved technical and clinical success with relatively low incidence of adverse events.

The effect of the dissolution process of hydroxyapatite added to conventional dental porcelain on its mechanical strength.

The use of phosphates in dental glasses and ceramics for the application as biomaterial is merging. Hydroxy apatite is characterized by its solubility in the oral fluids. Studying the effect of the dissolution process of hydroxy apatite added to conventional dental porcelain on its mechanical strength was our aim in this work. Five formulations were prepared from Egyptian raw materials and the mechanical strength of each investigated formulation was measured. It is found that addition of bone ash in amounts not exceeding 10% raised the tensile strength of the investigated dental porcelain. The rate of dissolution of dental porcelain containing bone ash increases with percentage of bone ash added, as the values of mechanical strength were lowered. The pH of the solution was affected by time of immersion. Calcium ions released from the dissolution of tricalcium phosphate readily react with silicon ions giving calcium silicate which render the solution alkaline.

Corrosion and metallurgical study of some porcelain fused to metal alloys.

In order to evaluate the corrosion behaviour of some dental alloys to be applied as base-metal for PFM, electrochemical technique and metallurgical investigation were used. Potentiodynamic and potentiostatic tests were carried out under deaerated and aerated conditions in 1% NaCl solution. The results have shown that Ni-Cr alloy has a superior corrosion resistance under deaerated conditions, whereas Co-Cr alloy has a stronger tendency to passivation under aerated conditions. Fe-Cr alloy has demonstrated a poor performance. The results were analyzed on compositional and microstructural bases.

Assessment of three different methods of tissue dilation for ceramometal restoration.

Tissue dilation is one of the key factors in obtaining accurate duplication of subgingival finishing lines and hence excellent marginal adaptation of the restoration. Elastic impression materials do not displace the tissue. Therefore, the tissue must be displaced away from the prepared teeth or a small ribbon of the free gingiva must be removed to expose the finishing line before making the impression.