Biomedical Engineering Reference
In-Depth Information
From ten patients samples of adherent supra- and subgingival periimplant biofilms
were collected around titanium implants. Similar samples were also taken at remain-
ing teeth for direct comparison of biofilms on implants and on teeth from the same
patient. As for the pacemakers the microbial communities were analyzed using SSCP
of 16S rRNA gene amplicons. The diversity of
Veillonella
,
Streptococcus
,
Parvi-
monas
,
Fusobacterium
and
Neisseria
species detected was remarkable. The presence
of various species of
Streptococcus
in the human mouth is well known and
Strepto-
coccus mitis
and
S. intermedius
could be identified. However, no sequence belonging
to the pathogen
Streptococcus mutans
was found confirming the asymptomatic nature
of the biofilms. The genus
Fusobacterium
comprises strictly anaerobic bacteria and
species of this genus are well known from the human mouth where they are important
members of biofilm communities [
20
]. The species
Fusobacterium naviforme
and
F.
canifelinum
were identified from the corresponding SSCP amplicons. Further well
knownmembers of asymptomatic dental biofilms,
Neisseria mucosa
and
Parvimonas
micra,
were also detected in this study. As expected, a high diversity of bacteria was
observed between biofilms of different patients [
21
]. Similar to the situation in the
gut each individual seems to have in its dental biofilms its own microbial community.
Applying multivariate analysis, however, revealed some bacteria species characteris-
tic for subgingival or for supragingival biofilms. No discrimination, however, could
be achieved between microbial species colonizing biofilms on implants or on resid-
ual teeth. This finding supports the view that biofilm communities on implants are
not much different to the natural ones on teeth [
22
].
2.4 Biofilms on Infected Dental Implants
Colonization of the implants by biofilms lead to peri-implantitis, an inflammation
of peri-implant tissues, and is currently seen as one of the main causes for early
implant failure. It is clinically characterized by inflammation of the mucosa and a
subsequent destruction of the bone around the implant. To determine the differences
in community composition between healthy and infected implants a similar analysis
was performed for biofilm communities from patients with infected implants. But
not only samples from the site of peri-implantitis but, where possible, also samples
from asymptomatic implants and residual teeth from the same patients were taken
and the biofilm communities analyzed.
As for the rhythmmanagement devices amuch higher diversity in bacterial species
were detected in the pathogenic biofilmcommunities compared to their asymptomatic
cousins (Fig.
3
). Remarkable is here that species known for their anaerobic lifestyles
dominated the biofilm communities indicating significant changes in the physiology
of the biofilms. Socransky et al. assessed a large number of microbial communi-
ties from plaque samples and correlated them with clinical data. Using multivariate
analyses they grouped the bacteria into five groups increasingly related to periodon-
titis [
23
]. These groups have also been applied in the assessment of peri-implantitis
although its pathogenesis is somewhat different to the one of periodontitis. In our
