Background/Aim: Mechanical properties, most significantly flexural strength of cold polymerized acrylic dental materials, used for denture reparation are lower compared to the equivalent hot polymerized materials. This paradox can be rectified by the aplication of alumina nanoparticles, which is the aim of this work. Methods: The liquid component of the commercial autopolimerized denture reline resin was modified with 0.05 %, 0.2 % and 1.5 wt. % 13 nm hydrophobic Al 2 O 3. These mixtures, along with the unmodified liquid, were mixed with the powder component to form test specimens. Flexural modulus and strength were tested, while the results were stastistically evaluated by one way ANOVA analysis followed by Tukey's test. Differential scanning calorimetry, scaning electron microscopy and energy dispersive x-ray analysis analyses were performed to assess the heat and fracture surface features. Results: Statistically significant increase in flexural modulus was obtained only for 0.2 % nanoparticle content, while flexural strength was significantly increased for specimens modified with 0.05 and 0.2 % nanoparticles. The rise of nanoparticle content to 1.5 % contributes to the formation of agglomerates, giving unsatisfactory mechanical properties. Also, the rise in glass transition temperature was noted for the most effective 0.05 and 0.2 % Al 2 O 3 contents. Conclusions: 0.2 % 13 nm Al 2 O 3 loading is the most effective in imropving the tested mechanical properties of cold polimerized poly(methyl methacrylate) reline resin.
Introduction. A percutaneous transhepatic approach has been used to place tunneled catheters for hemodialysis in the inferior vena cava. This route through the suprahepatic vein could be used to place a tunnelled catheter for permanent hemodialysis without complications and with an excellent permeability rate. Case report. From 2011 to 2020 at the Military Medical Academy, we treated 4 patients with the transhepatic central venous catheter for hemodialysis. All of them had exhausted approaches during the period of hemodialysis. Arterio-venous fistulas thrombosed on the arms, subclavian vein thrombosis bilaterally or superior and inferior vena cava thrombosis, as well as bilateral iliac and femoral vein thrombosis were present as complications of longterm hemodialysis through femoral catheters. Peritoneal dialysis was not possible. One patient needed a scroll catheter since the hemodialysis did not have a good outcome, and one patient needed a thrombolysis of catheter due to its malfunction. The other two patients have been on hemodialysis without complications for 300 and 1,650 days, respectively. Conclusion. Transhepatic venous access under ultrasound and radioscopic guidance is a simple and safe method. It is an acceptable alternative for permanent hemodialysis catheters when other venous accesses are exhausted and when it is performed by a well-trained team.
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