Fatigue lifetime and microbial inhibition at the implant–abutment interface of 5Y-PSZ zirconia abutments coated with experimental glass

Objective To evaluate microbial inhibition at the implant-abutment interface of 5Y-PSZ zirconia abutments coated with boron-doped soda-lime glass, with or without silver, and to evaluate the fatigue lifetime of boron-doped soda-lime glass-coated abutments compared to uncoated control. Methods Forty-five maxillary central incisor crowns and custom CAD/CAM 5Y-PSZ zirconia abutments were divided into three groups: Control, boron-doped soda-lime glass (BSL), and boron-doped soda-lime glass with silver (BSLAg). Microbial leakage at the implant-abutment interface was quantified by colony-forming unit (CFU) counts for Candida albicans, Streptococcus sanguinis, and Escherichia coli. Step-stress accelerated life testing (SSALT) was performed at 2 Hz with a stress ratio of 0.1 using a custom all-electric fatigue load frame. Survival probability and Weibull parameters were estimated with ALTA PRO software. Scanning electron microscopy (SEM) and fractographic analyses were conducted. CFU results were analyzed by one-way ANOVA (α = 0.05). Results The BSL group significantly reduced microbial leakage for all tested specimens (p < 0.05), whereas the BSLAg group showed no antimicrobial effect. Consequently, only the Control and BSL groups underwent fatigue testing. No significant difference could be detected between the groups after the fatigue lifetime analysis. SEM micrographs of the BSL group revealed reduced microbial adhesion. Fractures predominantly originated from bending of the titanium interfaces (Ti base) across all groups. Significance Boron-doped soda-lime glass coating on 5Y-PSZ zirconia abutments provides a dual benefit of antimicrobial protection and preserved fatigue lifetime. This approach may help hinder the development of peri-implantitis disease by reducing microbial leakage at the implant-abutment interface without compromising mechanical reliability.