Los Angeles Times
April 16, 2007
Gustavo
Rodriguez had expected numerous physical exams and blood tests before
checking into the hospital last July for a long-awaited kidney
transplant. But he was bewildered when told to see a dentist.
"My
gums were really bad, but I didn't know that mattered," says Rodriguez,
26, of Long Beach. "They said I had to be bacteria-free before my
surgery. I learned a lot ... like every little thing in your body
counts."
And as doctors and dentists now suspect,
gum disease is no little thing. Research compiled over the last five
years suggests that gum disease -- especially if the condition has
persisted for a long time without treatment -- can contribute to
diabetes, cardiovascular disease and stroke, pregnancy complications,
and perhaps even Alzheimer's disease, osteoporosis and some types of
cancers. Infections in the mouth also may increase the risk to people
undergoing several types of surgery, including transplantation and
cardiac valve replacement.
"For years the mouth was
never considered a part of the body," says Dr. Salomon Amar, a
periodontist at Boston University. "Gum disease was not considered
something that could have any impact."
But as
recently as last month, a study published in the New England Journal of
Medicine found that treating severe gum disease can improve the
function of blood vessel walls, improving heart health. And in this
month's Journal of Periodontology, two studies found periodontal
bacteria (bugs normally found in inflamed gums) in the arteries of
people with heart disease and in the placentas of pregnant women with
high blood pressure.
It's still too soon in the
evolution of this research to say with certainty that gum disease
directly causes other illnesses. But the evidence is compelling enough
that it's beginning to unite dental and medical professionals -- two
groups that have had only a nodding acquaintance.
And
it's leading to one of the most sweeping changes in the dental
insurance industry in more than a decade. Several health insurance
companies -- particularly those that offer both dental and medical
insurance -- are beginning to offer free or low-cost "enhanced" dental
benefits to certain high-risk patients who might experience broader
health benefits by having a cleaner mouth.
Inflammation's role
Gum
problems begin when the bacteria in plaque, the sticky film that forms
on teeth, persists long enough to inflame the gums. Usually,
inflammation is considered a positive response to bacteria -- a sign
that the body is fighting back. But if inflammation rages unchecked, it
does more harm than good.
The majority of Americans
have gingivitis, an inflammation of the superficial structure of the
gum that can be a precursor to gum disease. Although good brushing,
flossing and favorable genetics can limit the extent of gingivitis and
keep gum disease at bay, this condition of persistent inflammation
affects 30% to 40% of American adults. Of those, about 10% have
advanced cases that damage the structures (ligaments and bone) that
support the tooth.
Other than bleeding, gum disease
has few symptoms and rarely causes much discomfort. "The gums do not
hurt until it is too late," Amar says.
Well before
the gums or teeth start to hurt, the dual forces of infection and
inflammation in the mouth appear to hitch a ride in the bloodstream and
travel to other parts of the body, wreaking havoc once there. One of
the most well-established links between gum disease and secondary
infection, for example, is among people with mitral valve heart
defects. Doctors have long warned valve patients to take antibiotics
before teeth cleanings so that the bacterial disruption in the mouth
will not travel through the bloodstream to infect the valve.
The
other theory of how gum disease inflicts damage elsewhere in the body
involves inflammation. Bacteria in plaque release toxins that cause the
immune system to produce chemicals called cytokines. In excess,
cytokines can increase inflammation and damage tissues throughout the
body. Inflammation in general (no matter how it starts) is now
considered a prime culprit in the development of many illnesses,
including heart disease and some types of cancer.
"The
key in gum disease is chronic inflammation," says Preston D. Miller
Jr., president of the American Academy of Periodontology. "When it
becomes chronic, it begins to release substances that destroy tissue."
There
may be other ways that poor gum health causes trouble elsewhere in the
body. Doctors at USC have connected a common virus, cytomegalovirus, to
gum disease and complications in kidney transplantation. About 20% of
all failed kidney transplants are related to cytomegalovirus infection,
according to Hessam Nowzari, director of the periodontology program at
USC School of Dentistry. Research shows that inflamed gums can be a
reservoir for the virus.
"The virus originates and
replicates in inflamed gums," says Nowzari, who has studied the
connection. "That is going to lead to an attack on other parts of the
body, including transplants."
High-risk groups
Although
gum disease could worsen many conditions, experts and dental insurance
companies are most interested in heart disease, diabetes and pregnancy
-- conditions in which successful periodontal treatment could yield
ample benefits.
Studies surveying large groups show
that people with severe gum disease have significantly higher rates of
cardiovascular disease. Besides influencing the function of blood
vessel walls, byproducts from the bacterial infection can enter the
bloodstream and trigger the liver's release of a substance called
C-reactive protein, studies have suggested. C-reactive protein is
thought to inflame arteries and promote blood clot formation.
Now
researchers are testing whether treating severe gum disease will result
in fewer heart attacks, strokes and other cardiovascular problems.
Amar, for example, is studying whether treating gum disease
aggressively leads to fewer cardiac problems in people with both gum
disease and heart disease.
Intriguing links can also
be drawn between gum disease and diabetes. Diabetics tend to have more
severe gum disease and have it at an earlier age than people without
diabetes, research shows. Having gum disease increases the amount of
time a diabetic's blood sugar remains high. But diabetics who receive
good periodontal treatment have a better response to diabetes therapies.
"We've known for years that diabetic patients who have periodontal disease do not respond to therapy," says Miller.
A
study published last month in the Journal of Periodontology found that
gum disease even predisposes certain people to developing early signs
of diabetes.
But it's still too early to say if
aggressive treatment of gum disease in high-risk individuals could have
a big effect on other illnesses. A study published in November in the
New England Journal of Medicine serves as a cautionary tale and shows
why much more research on this subject is needed.
That
study tested whether treating gum disease in pregnant women could
reduce the risk of premature birth. Before the study, gum disease was
considered a likely cause of premature birth. Several studies suggested
that bacteria in infected gums could spread to the womb and initiate
early labor. And one study in Chile even showed treating gum disease in
pregnancy reduced preterm birth rates.
However, a
large, federally funded trial in this country found that treatment of
gum disease, while safe during pregnancy, did not cut the rates of
premature birth.
Studies are needed to conclusively
prove whether treating gum disease affects various conditions, says
Bryan Michalowicz, an associate professor at the University of
Minnesota School of Dentistry and lead author of the study.
"There are a number of criteria that have to be met before we can conclude that something is a cause," he says.
Insurer incentives
The
recent pregnancy study has given some experts pause, but so far it
hasn't derailed a sweeping trend among insurers to offer improved
dental care to certain high-risk members, such as pregnant women and
people with diabetes and heart disease.
Several
major insurance companies, including Aetna, Cigna and Delta Dental,
have revised their plans in the last year or so to offer extra
cleanings or additional dental services, such as paying for a
prescription mouthwash, to high-risk individuals.
The
insurers, particularly those who offer both medical and dental
insurance, think they'll save money in the long run, says Evelyn
Ireland, executive director of the National Assn. of Dental Plans in
Dallas.
An analysis by Aetna and Columbia University
College of Dental Medicine found that treating gum disease in high-risk
individuals improved their health and lowered overall medical costs.
Under
some plans, the member has to be referred by a physician to receive the
extra cleaning or dental service. And increasingly, physicians are
paying attention to their patients' oral health, says Miller. Just
recently, he received two referrals from medical clinics. In one case,
a patient was referred for treatment of gum disease before a transplant
surgery. In another, a patient was referred for assessment of his oral
health before he was cleared for valve replacement surgery.
"The leading medical centers are very aware of this and are actually requiring this before they do certain procedures," he says.
The
relationship between oral health and overall health could -- and some
would say should -- focus new light on the number of Americans who have
no dental insurance and go years without any care whatsoever. Though
about 44 million Americans lack medical insurance, at least 100 million
are not covered by dental insurance, according to a 2000 Surgeon
General report.
Says USC's Nowzari: "Even if we
convince the public of the link between gum disease and other
conditions, we have to face that challenge."
