Enzymatic and Biofilm Exposures on Surface Degradation and Corrosion Resistance of Dental Crowns

Authors

  • Farah Nabeel Mohammed Tahir AlKhayyat Lecturer at prosthodontic department/ College of Dentistry / Mustansiriyah University
  • Shaymaa Majid Abdulhamed
  • Madiha Fouad Jameel Al-Azzawi
  • Mustafa Nabeel Abdulghani

DOI:

https://doi.org/10.5195/d3000.2026.1444

Keywords:

Zirconia, Spectroscopy, Prosthodontics, Tooth Loss

Abstract

The objectives of the study were to assess the effect of enzymatic and microbial biofilm exposure on the surface roughness and corrosion resistance of dental crown materials commonly used in dentistry in oral environment. Three modern dental crown materials were used: yttria-stabilized tetragonal zirconia polycrystal (Y-TZP), lithium disilicate glass-ceramic, and cobalt–chromium metal-ceramic alloy. Ninety disc-shaped specimens were manufactured and randomized to three experimental groups: control (artificial saliva), enzymatic exposure and combined enzyme–biofilm exposure. Enzymatic degradation was simulated using matrix metalloproteinase-8 (MMP-8), esterase, and proteinase K. Biofilm formation was induced using Streptococcus mutans (ATCC 25175) and Lactobacillus acidophilus under anaerobic incubation. The surface roughness was measured by atomic force microscopy (AFM), and the corrosion resistance was measured by electrochemical impedance spectroscopy (EIS). The measurements were taken at 7, 14 and 28 days. Two-way ANOVA and repeated-measures ANOVA with Bonferroni post hoc testing were used for statistical analysis. All materials investigated showed an increase in surface roughness and loss of corrosion resistance after both the enzymatic and combined enzyme–biofilm treatments. The synergic effect had a greater degradation than the enzymatic effect (p < 0.05). The surface roughness values remained as low as zirconia and the impedance values remained as high as zirconia throughout the experimental period. The specimens of metal-ceramic exhibited the lowest corrosion resistance and the highest increase in roughness with time. The surface degradation and corrosion experiments of dental crown materials indicated that both enzymatic and microbial biofilm exposure had great effects on the surface degradation and corrosion behavior of the materials under simulated oral conditions. Bacterially mediated degradation was found to be more resistant for zirconia than for lithium disilicate and metal-ceramic materials.

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Published

2026-07-22

Issue

Vol. 14 No. 2 (2026)

Section

Adults & the Elderly

License

Copyright (c) 2026 Farah Nabeel Mohammed Tahir AlKhayyat, Shaymaa Majid Abdulhamed, Madiha Fouad Jameel Al-Azzawi, Mustafa Nabeel Abdulghani

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