Incorporation of staphylococci into titanium-grown biofilms: an invitro "submucosal" biofilm model for peri-implantitis

ObjectivesStaphylococcus spp. are postulated to play a role in peri-implantitis. This study aimed to develop a submucosal invitro biofilm model, by integrating two staphylococci into its composition. Materials and methodsThe standard subgingival biofilm contained Actinomyces oris, Fusobacterium nucleatum, Streptococcus oralis, Veillonella dispar, Campylobacter rectus, Prevotella intermedia, Streptococcus anginosus, Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola, and was further supplemented with Staphyoccous aureus and/or Staphylococcus epidermidis. Biofilms were grown anaerobically on hydroxyapatite or titanium discs and harvested after 64h for real-time polymerase chain reaction, to determine their composition. Confocal laser scanning microscopy and fluorescence insitu hybridization were used for identifying the two staphylococci within the biofilm. ResultsBoth staphylococci established within the biofilms when added separately. However, when added together, only S.aureus grew in high numbers, whereas S.epidermidis was reduced almost to the detection limit. Compared to the standard subgingival biofilm, addition of the two staphylococci had no impact on the qualitative or quantitative composition of the biofilm. When grown individually in the biofilm, S.epidermidis and S.aureus formed small distinctive clusters and it was confirmed that S.epidermidis was not able to grow in presence of S.aureus. ConclusionsStaphyoccous aureus and S.epidermidis can be individually integrated into an oral biofilm grown on titanium, hence establishing a submucosal biofilm model for peri-implantitis. This model also revealed that S.aureus outcompetes S.epidermidis when grown together in the biofilm, which may explain the more frequent association of the former with peri-implantitis.