The parameters of abrasive blasting process directly affect the condition of the metal surface, changing the degree of surface roughness and wettability, depending on the size of the used particle, the pressure or type of abrasive. The aim of this study was to analyze the condition of Ni-Cr alloy surface after abrasive blasting using various process variants. The samples were blasted by Al 2 O 3 abrasive using various particle sizes and pressures of the process. Basic and specific roughness parameters were investigated, and a surface wettability test was performed, and the percentage share of abrasive particles penetrated in the surface after abrasive blasting was also examined. The most considerable differences in the condition of the surface were observed with the change in the particle size of Al 2 O 3. Statistical analysis confirmed the statistical significance of all these relationships.

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Purpose: A review regarding the mechanisms of metal-ceramic join is presented. Design/methodology/approach: The impact of the air-abrasion parameters on the mechanical bond strength of the ceramic crowns was discussed. The presence of opaque on the chemical bond was analysed. Research of the influence of the difference in the coefficient of thermal expansion values on the metal-ceramic bond was included. The methods of testing the bond strength were analysed. Findings: The metal substructure-dental ceramic bond strength is affected by all types of bond. In bond strength, 3-point bending test and shear test are mainly used. Created samples simulate the ceramic crowns veneered on one side. The role of physical bond on ceramic crowns veneered around metal substructure is unknown. Research limitations/implications: The prosthetic restorations with the ceramic surrounding whole the metal substructure are commonly used. The impact of shrinkage in the cylindrical deposition of the ceramic on metal substructure should be analysed. Practical implications: Numerical analysis and FEM simulation can be helpful in the analysis of the physical bond between the metal substructure and the dental ceramic around it. Originality/value: The impact of the type of the bond to metal-ceramic bond strength is presented, taking into account the cognitive gap in the influence of the coefficient of thermal expansion on the cylindrical placement of ceramic on the substructure.

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Summary Background Hybrid manicure is now a popular method of nail care and nail art, which is associated with its durability. Unfortunately, it has an adverse effect on pH, TOWL and overall nail plates condition and has not been investigated in detail so far. Aims The aim of this study was to compare the pH and TOWL of the hand nails after using different primers. The effect of application time, breaks between applications and the method of curing and removal on those parameters and overall nail plates condition were evaluated. Patients/Methods An evaluation survey was conducted among 116 women. pH and TOWL measurements of the nail plate in 35 women were taken using the Courage & Khazaka. Clinical photos were made using the Fotomedicus system. Results The measured pH values of the nail plate in the test group with gel polish hybrid on the nails were from 5.50 to 6.65, while after removal of the gel polish hybrid, the values ranged from 5.63 to 6.68. TOWL of the nail plate covered with gel polish hybrid ranged from 2.9 to 33.2 g/m2/h, whereas after removal of hybrids—from 1.9 to 45.7 g/m2/h. Conclusion Different forms of acid‐free primers maintain a lower pH of the nail plate covered with a gel polish hybrid, while the acidic primer maintains higher values of the nail plate pH. The significant decrease in the nail plate TOWL following the application of gel polish hybrid indicates a reduced loss of water from the surface of the nail to the atmosphere.