Microbial findings at failing implants

Aim of the study

In this Swedish study, the authors seek to determine the qualitative and quantitative differences in the subgingival flora around Brånemark implants with healthy and diseased peri-implant tissues.

Materials and methods

The healthy group comprised 51 individuals with 1-3 implants each. The diseased group (with bone loss exposing > 3 threads after 1 year) comprised 37 individuals with 1-4 implants. Individuals were placed in the diseased group if they showed radiographic evidence of marginal bone loss, inflamed mucosa and absence of those signs which characterise peri-implant health.

Results

60 % of patients with peri-implantitis harboured bacteria implicated in periodontal pathologies, such as Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens or Actinobaccillus actinomycetemcomitans. Nevertheless, 55 % of diseased sites showed the presence of bacteria not associated with periodontal inflammation, such as Staphylococcus spp, some enterobacteria and Candida spp. Conversely, implants at healthy sites exhibited a flora comparable to that associated with healthy gingiva.

Conclusion

A clear qualitative difference was shown between the bacterial flora at diseased periodontal or peri-implant sites, particularly by the presence in the latter of staphylococci, enteric bacteria and yeasts, which were found in similar quantities to the periodontal pathogens normally described.

Commentary

This study confirmed, once again, the varied nature of the sub-gingival bacterial flora associated with diseased peri-implant sites (cf. Mombelli 1987 or Becker 1990). This information should enable us to improve our targeting of antimicrobial therapy so that where antibiotic or antiseptic treatment is indicated, then reliable diagnostic bacteriological tests can be established.