Biofilm Control Strategies in Dental Health - Antibiofilm Agents: From Diagnosis to Treatment and Prevention - page 285

microbiome (Peterson et al. 2013 ; Wade 2013 ; Zaura et al. 2009 ). These studies
have confirmed the high diversity of the oral microbiome as well as the main traits
in composition already described in previous studies where the predominant taxa in
healthy samples belonged to Firmicutes (genus Streptococcus , family
Veillonellaceae , genus Granulicatella ), Proteobacteria (genus Neisseria ,
Haemophilus ), Actinobacteria (genus Corynebacterium , Rothia , Actinomyces ),
while Bacteroidetes (genus Prevotella , Capnocytophaga , Porphyromonas ) and
Fusobacteria (genus Fusobacterium ) appear to be more associated with disease.
Important factors for shaping the composition and structure of oral biofilms are
the highly variable conditions in its environment. Access to nutrients follows the
daily intake by the host, with long periods of low concentrations of nutrients
followed by short periods of high concentrations of a large variety of different
nutrients. These fluctuations have a major impact in selecting the species of bacteria
that can survive and colonize the oral cavity.
In this brief review we present the main strategies that have been used to control
the growth and composition of oral biofilms and other biofilms important in dental
health and a final summary of future directions that could lead to better control of
the communities present in the oral cavity.
2 Biofilm-Associated Oral Diseases
In healthy individuals the oral microbial biofilm is in homeostasis with its environ-
ment and the host. However, changes in response to variations in host physiology
and environmental factors may lead to a shift from a health-associated biofilm to a
disease-associated biofilm. The nature of these changes is not completely under-
stood and is the focus of an important part of research in oral microbiology studies.
Two of the most common human diseases, caries and periodontal disease, are the
result of a healthy microbial biofilm becoming a dysbiotic one due to mechanisms
not completely understood. These are special cases of infectious diseases in that the
origin of the infection is not an exogenous organism but a commensal organism that
somehow overgrows and modifies the features of the microbial biofilm to its
advantage.
Dental caries is caused by an overgrowth of acidogenic organisms usually linked
to a diet rich in fermentable carbohydrates that can be used as nutrients by the
microorganisms growing in the oral biofilm, resulting in the release of lactic acid to
the surface of the tooth and leading to the formation of cavities characteristic of
dental caries. Most cases of caries can be associated with the presence of high
numbers of Streptococcus mutans or Lactobacillus as the main organisms respon-
sible for the production of acid on the teeth (Loesche et al. 1975 ; Takahashi and
Nyvad 2011 ). Nonetheless, the colonization of S. mutans is the result of ecological
changes in the environment and shifts in the structure of the biofilm. Among
important virulence factors of this pathogen, its ability to form and sustain a biofilm
is vital not only to its survival and persistence in the oral cavity but also for its