Exploring antimicrobial soda-lime glasses as glaze alternatives for 4Y-PSZ

To evaluate the mechanical, optical, and antimicrobial effects of two experimental soda-lime glass coatings on 4Y-PSZ comparing it to a commercial glaze.

Experimental soda-lime (SL) and silver-containing soda-lime (Ag) glasses were developed. Disc-shaped 4Y-PSZ ceramic (Katana STML) specimens were prepared and divided according to the coating material: SL, Ag, or commercial glaze (G, Cerabien Zr). The experimental glass powders mixed with propylene glycol or glaze paste were applied and fused onto zirconia discs. Specimens underwent roughness (Ra, Rz), translucency (TP₀₀), biaxial flexural strength, and x-ray diffraction analyses. Coated and fractured surfaces were evaluated in scanning electron microscope. Colony forming units (CFU) of Candida albicans, Streptococcus sanguinis, and Streptococcus mutans analyses were performed with initial and 6-month water-aged specimens. Statistical analysis was performed with Weibull statistics, Kruskal-Wallis, or ANOVA tests.

Ra, Rz, TP₀₀, flexural, and characteristic strengths were similar among all groups. Weibull modulus of SL was higher than Ag. SL and Ag specimens failed from bulk zirconia defects while G fractures originated at the glaze-zirconia interface. SL and Ag microstructure shows oriented crystalline phase. Surface coating did not affect C. albicans CFU. However, SL showed less hyphal form. SL decreased CFU of S. sanguinis and S. mutans at both initial and aged analysis, while Ag reduced these microorganisms only after aging.

SL and Ag experimental glasses provided antimicrobial effect without harming flexural strength, translucency, or roughness of 4Y-PSZ as compared to commercial glaze. SL revealed both initial and long-term antimicrobial effect and avoided C. albicans hypha formation.