Effect of Enterococcus faecalis biofilm on corrosion resistance in titanium submitted to different surface treatments

Author(s)

Jadison Junio Conforte

• Document type: Master's Dissertation
• Press: Araçatuba. 2019-07-30.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Odontologia. Araçatuba
• Defense date: 2019-06-03
• Advisor: Wirley Gonçalves Assunção; Cristiane Duque

Abstract

The objective of this study was to evaluate, in vitro, the corrosion in different surfaces of Titanium commercially pure-Grade 4 (Ticp-G4) as a function of the bacterial biofilm effect of Enterococcus faecalis. 57 disks were randomly divided according to the surface (n = 19): Group I machined surface (USI); Group IIsurface textured by double acid attack (D.A.) and Group III surface textured by double acid etching and zirconia (D.A.Zir). For microbiological analysis (n = 9), the discs were positioned in 24-well plates containing Enterococcus faecalis culture at 1.5 x 10 5 cells / ml in broth BHI medium and incubated for 168 hours (7 days) at 37 ° C. period the discs were removed and the bacteria adhered on its surface were evaluated by means of Colony Forming Units / mL (CFU / mL) counts. For corrosive analysis (n = 5), new specimens were inoculated in the same way in E. faecalis culture and after 7 days, they were destined to the electrochemical test by means of electrochemical impedance spectroscopy (IEE) using BHI and biofilm electrolytes and BHI sterile broth. The results were submitted to statistical analysis: microbiological (ANOVA with Tukey post test, 5%) and electrochemical test (ANOVA 2 Factors and post test Tukey 5%). In the evaluation of bacterialcell count, only D.A.Zir (mean 34 CFU / ml) differed from USI (mean 16 CFU / ml) (p = 0.034), but not D.A. (24 CFU / ml). In electrochemical impedance spectroscopy, for Nyquist and BODE, the D.A.Zir (Biofilm) group showed worse electrochemical behavior. For resistance to polarization the USI (BHI) had better ion exchange resistance with the medium. For the electrochemical study D.A.Zir (Biofilm) had the worst electrochemical behavior and the USI group (BHI) had better ability to resist ionic exchanges. It was concluded that there was a higher biofilm formation for the D.A.Zir group, with a higher electrochemical exchange for D.A.Zir (Biofilm) and the biofilm presence favored a greater electrochemical exchange with the medium. (AU)

• FAPESP's process: 17/11471-5 - Mixed bacterial biofilm effects on corrosion kinetics in alloys of Ticp-G4 with different surface treatment
• Grantee: Jadison Junio Conforte
• Support Opportunities: Scholarships in Brazil - Master