Abstract
Oral biofilms are some of the most complex and
diverse ecosystems developed by successive colonization of
more than 600 bacterial taxa.
Development starts with the
attachment of early colonizers such as Actinomyces species
and oral streptococci on the acquired pellicle and tooth enamel.
These bacteria not only adhere to the tooth’s surface, but
also interact with each other and lay foundation for attachment
of bridging colonizers such as Fusobacterium nucleatum
followed by late colonizers including the red complex species
Porphyromonas gingivalis, Tannerella forsythia, and Treponema
denticola, the founders of periodontal disease.
As the biofilm progresses from supragingival sites to subgingival
sites, the environment changes fromaerobic to anaerobic, thus
favoring the growth of mainly Gram-negative obligate anaerobes
while restricting the growth of the early Gram-positive
facultative aerobes.
Microbes present at the supragingival
level are mainly related to gingivitis and root caries, whereas
subgingival species advance the destruction of teeth
supporting tissues, and thus cause periodontitis. This review
summarizes our present understanding and recent developments
on the characteristic features of supra- and subgingival
biofilms, interaction between different genera and species of
bacteria constituting these biofilms, and draws our attention to
the role of some of the recently discovered members of the
oral community.