Evaluation of stresses on mandible bone and prosthetic parts in fixed prosthesis by utilizing CFR-PEEK, PEKK and PEEK frameworks.

Fixed prostheses are appropriate treatment solutions for edentulous patients. In fixed prostheses, following "All on four", titanium frameworks are commonly used to support the implants. However, the limitations of titanium have prompted researchers to search for alternative materials (e.g. polymers). This study applied finite element investigation to evaluate the stress distribution in the parts of fixed prosthesis and the surrounding bone tissue, using polymeric frameworks in place of titanium, and different densities of spongy bone. As, the success of fixed prosthesis was predicted to be influenced also by bone quality, particularly spongy bone density. Fixed prosthesis was constructed on edentulous mandible, then different frameworks (CFR-PEEK 60%, CFR-PEEK 30%, PEKK, and PEEK) were stimulated instead of titanium, under 300N unilateral and bilateral forces. Three densities of spongy bone were stimulated which are normal, low and high. The choice of framework material depended on the density of spongy bone. Moreover, PEEK framework showed the lowest stress values on bone tissues and the highest stress values on mucosa. All frameworks could be used in the fixed prosthesis, in the cases of normal and high densities of spongy bone. In low-density case, soft frameworks (PEKK and PEEK) were recommended to reduce the stresses generated on bone tissues.

Synthesis and characterization of berberine-loaded chitosan nanoparticles for the protection of urethane-induced lung cancer.

Lung cancer is one of the most common types of malignant tumors of the respiratory system and has the highest rates of incidence and mortality of malignant tumors. This study aimed to synthesize and characterize berberine-loaded chitosan nanoparticles (BBR-COSNPs) and to evaluate their protective effects against urethane-induced lung cancer. Forty male albino mice were divided into four groups, with the first serving as a negative control and the other three groups were injected intraperitoneally with urethane (1 mg/kg b.w) each other day for 1 week then group 2 was served as a positive control, however, groups 3 and 4 were treated orally with a daily dose of BBR or BBR-COSNPs (75 mg/kg b.w) for 10 consecutive weeks. Blood and lung tissue samples are collected for laboratory assay. The BBR-COSNPs were spherical, with an average particle size of 45.56 nm and zeta potential of 39.82 1.82 mV. The in vivo data demonstrated that mice given urethane alone had a significant increase in MDA, NO, NF-κB level, HIF1-α, and COX-2-positive expression in the lung tissue and serum VEGFR2, ALT, AST, urea, and creatinine accompanied with a significant decrease in GSH, SOD, caspase 9 in the lung tissue and serum BAX. Co-treatment with BBR-COSNPs suppressed lung cancer growth and promoted apoptosis by modulating serum BAX and lung caspase 9 gene expressions. In addition, BBR-COSNPs inhibited tumor angiogenesis by reduction in levels of serum VEGFR2 and lung HIF 1 gene expression. It is possible to conclude that BBR-COSNPs can be used in oral administration formulations for lunganticancer therapy.