How Poor Oral Health Fosters Systemic Disease
Researchers have long assumed a connection
between oral and general health, but they only
began to explore it broadly in the 1990s. They found
that periodontal disease results from a complex
interplay between oral bacteria and the innate and
adaptive immune responses. Moreover, they found
the relationship could extend beyond the mouth,
potentially contributing to certain systemic diseases.
In 2012, more than 70 leading researchers
who focused primarily on the connection between
periodontitis and cardiovascular disease (CVD),
diabetes and adverse pregnancy outcomes, found out
that associations indeed exist.
In a healthy mouth, bacterial species live in
homeostasis, and they gather in dental biofilms,
known as plaque, that accumulate throughout the
mouth. Trouble arises when homeostasis is lost. As
plaque builds up, it can migrate below the gum line into
an anaerobic environment, where certain pathogenic
bacteria thrive. The infected tissue releases some
chemical signals along with an immune response,
attracting immune cells to the infection, while also
secreting chemical signals that recruit other types of
immune cells. Immune responses typically resolve
quickly if they manage to remove the plaque. However,
in those susceptible to periodontitis — due to
genetics, behaviors like smoking and poor nutrition or
a systemic vulnerability — the inflammation becomes
chronic. When that occurs, tissues tend to create
ulcerations under the gum line and pockets that allow
anaerobic pathogens to flourish. The damage can
spread to ligaments and bone supporting the teeth,
causing deterioration and tooth loss.
Of the 57 possible systemic conditions in
connection with periodontal disease, diabetes has
yielded the clearest evidence. Clinical studies show
that among patients with poorly controlled diabetes,
elevated levels of pro-inflammatory mediators and
other factors within the gingival tissues contribute
to increased periodontal destruction. According to
Professor Iain Chapple, in Birmingham, England, the
bidirectional relationship between periodontitis and
diabetes is largely accepted. However, Chapple says,
diabetes is far from the only disease that shows a
connection to periodontal disease.
The situation is similar with adverse pregnancy
outcomes. Studies involving women with periodontal
disease have found periodontal pathogens
translocated to the placenta, but how this could lead to
an adverse outcome is still not clear. Maria Geisinger,
the director of advanced education in periodontology
at Birmingham School of Dentistry, points out that
pregnant women tend to be younger and many will
have pregnancy-related gingival inflammation.
In one recent study, though, Geisinger treated
women for gum disease in conjunction with their
regular maternity visit. She reported a 50% reduction
in preterm births and low birth-weight when compared
with historical clinical trials.
When it comes to an association between heart
disease and periodontal disease, evidence ∃, but
it has not reached the level of a causal relationship.
A consensus report from the European Federation
of Periodontology and the World Heart Federation,
published last year, confirms a positive association
between periodontitis and CVD caused by bacteria
moving into the circulatory system, promoting
inflammation and hardening of the arteries.
Rich Lamont, a professor at the University of
Louisville, Kentucky, has been probing the bacterial
community itself for clues to treatments. By learning
how microorganisms communicate within the biofilm,
Lamont says, “We are starting to understand the
physical and chemical messages which can either
attract or repel. We want to be in a situation where we
can recruit the organisms we want and get rid of the
pathogens we don’t want and prevent the transition
from healthy plaque to a disease-provoking plaque.”
Indeed, most new therapies will have to take into
account that the mouth is a dynamic system and that
the science will continue to evolve. “When we look
at our entire understanding of the microbiome and
how that shapes overall wellness, it’s been such a
paradigm shift in my practice lifetime,” Geisinger
says. “Instead of looking at discrete bacteria we are
looking at commensal or dysbiotic biofilm. We should
see our oral microbiome as a partner in our immune
system and in our well-being.”
Available at: https://www.scientifi camerican.com/custom-media/ healthy-mouth-healthy-body/how-poor-oral-health-fosters-systemic- -disease/?mvt=i&mvn=678a35e4bc844151b32c9bea2fb15845&mvp =NA-SCIEAMERLIVE-11237933&mvl=TopicAgenda. Retrieved on: 17, Jul. 2021. Adapted.
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