Microbiome Diversity of Titanium or Zirconia Implant-related Oral Biofilm

Objectives: Our purposes were to utilize culture-independent molecular techniques (1) to extend our knowledge on the microbial diversity of biofilm associated with titanium or zirconia implant-abutments in the healthy human oral cavity, including not-yet-cultivated bacteria species, and (2) to identify and quantify species recovered from peri-implantar or periodontal sulci, supragingival biofilm of tooth and implant-restorations and from the internal parts of the implants. Clinical outcomes (probing depth, clinical attachment level and bleeding on probing) and marginal bone level were also evaluated over the time and correlated with the biofilm formation.
Methods: Single-unit implant-supported restorations were placed in 20 clinically healthy participants and followed during 6 months of loading. DNA Checkerboard and 16S rDNA Pyrosequencing were used to quantify and to determine species identity, respectively.
Results: 161 bacterial taxa representing 12 different phylotypes were reported, of which 25% were non-cultivable. Species common to all sites belonged to the genera Fusobacterium, Prevotella, Actinomyces, Porphyromonas, Veillonella and Streptococcus. While some species were subject specific and detected in most sites, other species were site specific. Unclassified species were found colonizing zirconia-related sites. Moderate to high levels of pathogenic and non-pathogenic species were detected colonizing oral sites in both materials. Titanium-related sites presented the highest total microbial count and higher counts of pathogenic species.
Conclusions: Our results revealed differences in relation to the microbial diversity and microorganisms counts in the oral biofilm associated with titanium or zirconia abutments. Data suggested a correlation between microbiological findings and clinical outcomes.