In vivo evaluation of Candida spp. adhesion on titanium or zirconia abutment surfaces

Candida spp. have been found colonising implant sites in healthy or diseased subjects. The aim of this in vivo study was to evaluate the Candida spp. adhesion on machined or cast titanium and zirconia (Zc) abutment substrates.

Six healthy subjects were enrolled in this randomised crossover clinical investigation. The study was conducted in three phases according to evaluated substratum. Participants were advised to use an intraoral splint containing four discs of the same tested substrate for 24h. Two discs were located in the anterior region and two in the posterior region. DNA checkerboard hybridisation method was used to detect and quantify five different Candida species. Data on the surface roughness and the total area of discs covered by formed biofilm were also provided to correlate the species and biofilm found between different substrates.

Zc presented the highest means of surface roughness. Total area of the biofilm covering was not different in the tested groups. Moderate to high levels of target microorganisms were recorded for all the tested substrates. Zc showed the lowest indices, followed by machined pure titanium (MPT) and cast and polished titanium (CPT). Candida albicans and Candida krusei were not detected in the Zc group. The region of disc placement did not show differences in relation to Candida adhesion.

There was a significant difference in the total cell count between the three groups. CPT presented the higher mean counts, followed by MPT and Zc. There was no positive correlation between the cell counts recorded and the surface roughness or total area of formed biofilm.