Effects of different sterilization methods on surface characteristics and biofilm formation on zirconia in vitro

Aifang Han, James K.H. Tsoi, Jukka P. Matinlinna, Yu Zhang, Zhuofan Chen

Research output: Contribution to journalArticlepeer-review


Objective: The current laboratory study was to investigate the effect of different sterilization treatments on surface characteristics of zirconia, and biofilm formation on zirconia surface after exposure to these sterilization treatments. Methods: Commercially available zirconia discs (Cerconbase, Degu-Dent, Hanau, Germany) were prepared and polished to the same value of surface roughness. The discs were treated with one of the following sterilization methods steam autoclave sterilization, dry heat sterilization, ultraviolet C (UVC) irradiation, and gamma (γ) ray irradiation. The characteristics of zirconia surfaces were evaluated by scanning electron microscopy (SEM), surface roughness, surface free energy (SFE), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) measurements. Then, Staphylococcus aureus (S.a.) and Porphyromonas gingivalis (P.g.) bacteria were used and cultured on the respective sterilized zirconia surfaces. The amount of biofilm formation on zirconia surface was quantified by colony forming unit (CFU) counts. Results: Significant modifications were detected on the colour and SFE of zirconia. The colour of zirconia samples after UVC irradiation became light yellow whilst dark brown colour was observed after gamma ray irradiation. Moreover, UVC and gamma ray irradiation increased the hydrophilicity of zirconia surface. Overall, dry heat sterilized samples showed the significantly lowest amount of bacteria growth on zirconia, while UVC and gamma ray irradiation resulted in the highest. Significance: It is evident that various sterilization methods could change the surface which contribute to different biofilm formation and colour on zirconia.

Original languageEnglish (US)
Pages (from-to)272-281
Number of pages10
JournalDental Materials
Issue number2
StatePublished - Feb 2018


  • Bacteria
  • Colour
  • Gamma ray
  • Sterilization methods
  • UV
  • Zirconia

ASJC Scopus subject areas

  • General Materials Science
  • General Dentistry
  • Mechanics of Materials


Dive into the research topics of 'Effects of different sterilization methods on surface characteristics and biofilm formation on zirconia in vitro'. Together they form a unique fingerprint.

Cite this