Content uploaded by Debora Matthews
Author content
All content in this area was uploaded by Debora Matthews on Mar 20, 2016
Content may be subject to copyright.
t h E J c d a i n t E r v i E wJ c d a p a n E l d i s c u s s i o n
JC DA •JC DA • ww w.cda -adc .ca /jcd a • April 20 07, Vo l. 73, No. 3 • 211
Oral Health–Systemic Health:
What Is the True Connection?
JCDA rst turned to Dr. Howard Tenenbaum,
who has recently done a lot of work on the oral–
systemic connection both for the Ontario Dental
Association and the Royal College of Dental
Surgeons of Ontario.
JCDA: Dr. Tenenbaum, in your opinion what
are the most important factors to consider when
reecting on the oral health–systemic health
connection?
Dr. Howard Tenenbaum (HT): Certainly there
are the articles in the scientic literature to con-
sider, those that highlight the potential links
between overall health and oral conditions in
general and with periodontal disease in par-
ticular. While this focus on disease is important,
I believe we must also look at the fact that there
is evidence to show that the tissues of the oral
cavity can act as a biological model for how tis-
sues in any part of the body behave. If we wish
to study cellular physiology at any level, from
simple cell culture experiments right down to
the most intricate cell signalling, we can use
periodontal tissues, gingival tissues, bone or
ligament to model these other systems.
For example, it might be easier to obtain
samples of periodontal tissue rather than car-
diac tissue to study basic biological processes.
We know that we can learn things from these
studies of oral tissues that are applicable to other
systems in the body.
JCDA: Are you thinking of the mouth as being a
“window to the body” in this respect?
HT: e mouth can of course reect the pres-
ence of other diseases. However, from my own
perspective as a scientist, I still believe that the
most important aspect of this “window” con-
nection is at the level of basic cell biology where
the mouth tissues present a model for studying
other conditions. If we nd something in the
laboratory that might have a benecial action
In recent years, the dental and medical literature as well as the mainstream media have featured a number of articles
that highlight links between oral health and general health. Some of these articles have been emblazoned with dramatic
headlines while others have been more responsible in cautiously pointing out emerging evidence of possible connections
between oral conditions and systemic conditions.
At present there seems to be some debate in the dental profession, allied professions and among the public about
the level of evidence surrounding these connections. Do oral conditions cause systemic conditions, or vice versa? What
messages should individual dentists and dental organizations be broadcasting about the oral health–systemic health
connection?
To take stock of the current state of understanding of the oral–systemic link, JCDA convened a panel of Canadian
subject experts to reect upon various aspects of this important topic. Drs. Howard Tenenbaum, George Sándor and
Chris McCulloch of the University of Toronto and Dr. Debora Matthews of Dalhousie University all agreed to participate
in this discussion.
The Panel
Howard Tenenbaum,
DDS, PhD, Dip Perio,
FRCD(C)
Debora Matthews,
BSc, DDS, Dip Perio, MSc
George Sándor,
MD, DDS, PhD, FRCD(C),
FRCSC, FACS
Christopher McCulloch,
BSc, DDS, Cert Perio,
PhD, FRCD(C)
212 JCDA • www.cda-adc.ca/jcda • April 2007, Vol. 73, No. 3 •
––– JCDA Panel Discussion –––
on any particular type of cell or tissue, we must ask
if that same benecial action can be replicated in the
cells or tissues of another body system.
I believe that health researchers focusing on dif-
ferent body systems are simply at dierent points in
a continuum, and when we talk about the oral and
systemic connection, we have to think of physiology
as well as disease.
JCDA: So you feel that there should be a greater em-
phasis placed on physiology rather than disease?
HT: We have to avoid a trap — one that I think we
may have fallen into recently — where the profes-
sion might be trying to increase the public percep-
tion of the importance of oral health by showing
that it has an impact on systemic health. It’s almost
as if we feel pressure to justify the importance of
dental treatment by highlighting its impact on car-
diac disease, for example.
I reject this approach and contend that oral
health is simply a component of health and should
not be thought of as being somehow separate from
the health of the rest of the body. As a result of an
oral condition, a person may be in pain, feeling
poorly or not eating properly, and these problems
are manifestations of poor overall health. A person
is simply not well systemically if they are not well
orally. is is not to minimize the putative or proven
connections between oral inammatory disease and
systemic disease, mind you.
Dr. Tenenbaum mentions the connections between
oral inammatory disease and systemic conditions
— but what is the strength of the evidence under-
pinning this relationship? JCDA asked Dr. Debora
Matthews, a leader in evidence-based dentistry at
Dalhousie University, to help summarize the current
understanding.
JCDA: Dr. Matthews, according to the latest re-
search, what are the main systemic conditions that
have been linked to periodontal conditions?
Dr. Debora Matthews (DM): e most signicant
is diabetes, but more recently we’ve been looking
at cardiovascular disease, in particular myocardial
infarct and stroke, respiratory diseases and pre-
term, low-birth-weight babies.
With respect to diabetes and periodontal dis-
ease, several well-designed studies have demon-
strated a bidirectional relationship between the 2
conditions. ere is good basic scientic research
as well as good clinical and survey research linking
these 2 diseases. Randomized clinical trials have
shown that people with diabetes are 2.5 to 4 times
more likely to develop periodontal disease than
non-diabetics. ese trials also show that treating
periodontal disease can stabilize the glucose status
in diabetic patients.
JCDA: So diabetes seems to have the strongest
evidence of a bidirectional relationship with peri-
odontal disease. What about the other systemic
conditions?
DM: ere appears to be a relationship, but not ne-
cessarily in both directions, between the presence
of untreated periodontal disease and the risk for
having a heart attack or a stroke, and similarly for
respiratory diseases and for pre-term, low-birth-
weight babies.
I would classify the evidence for myocardial in-
farct as moderately strong. ere have been 3 recent
systematic reviews, the strongest of which found
that there was a small increased risk of coronary
heart disease over and above the traditional risk
factors such as hyperlipidemia, obesity or smoking.
is risk was particularly increased in people under
the age of 65. e strongest systematic review fo-
cused on prospective studies — which always pro-
vide the best evidence — and it found close to a 20%
increase in risk of fatal heart attack in the presence
of periodontal disease.
As for the studies
examining the relation-
ship between periodontal
disease and stroke, the
evidence is somewhat
mixed. I would call it a
strong but small asso-
ciation. e same applies
for respiratory diseases
and pre-term, low-birth-
Dr. Howard Tenenbaum
“I belIeve that health researchers focusIng on dIfferent
body systems are sImply at dIfferent poInts In a contInuum,
and when we talk about the oral and systemIc connectIon
we have to thInk of physIology as well as dIsease.”
JC DA •JC DA • ww w.cda -adc .ca /jcd a • April 20 07, Vo l. 73, No. 3 • 213
––– JCDA Panel Discussion –––
weight babies. More systematic reviews that include
prospective studies must be done to denitively
determine the relationship of periodontal disease
with both of these systemic conditions.
JCDA: What are some of the challenges in trying to
establish the strength of these relationships?
DM: We have to consider causality, but it’s always
dicult to tell which condition comes rst. In
other words, is the damaged immune system in a
diabetic making periodontal disease worse or is
periodontal disease in fact impairing the glucose
control of a diabetic? To eectively answer such
questions, a study must ideally establish temporality,
specicity and a dose response gradient. e chal-
lenge is that all chronic diseases are multifactorial,
which makes it extremely dicult to account for
all risk factors — such as genetics, socioeconomic
status and environmental inuences — for diseases
being linked with periodontal conditions.
e concept of the mouth as a window to the body
arose in the initial discussion with Dr. Tenenbaum.
Can the mouth be used as a “diagnostic” window to
the body? JCDA approached Dr. George Sándor, a
doubly qualied dentist and physician, to shed some
light on what can be ascertained about systemic
health by looking into a patient’s mouth.
JCDA: Dr. Sándor, when you look into a patient’s
mouth, what does it tell you about the general
health of a patient?
Dr. George Sándor (GS): It actually starts well
before an examination of the mouth, because as
practitioners we need to be excellent observers
and excellent listeners. Observing can begin as
your patient shues into your operatory and you
may suspect that he has Parkinson’s disease or if
he drags one foot behind the other, you may con-
sider a history of hemiplegia and stroke. Listening
can begin by taking a de-
tailed medical history of
your patient.
en as we examine
the mouth, we might no-
tice that the teeth look
very shiny, that the layer
of enamel on the occlusal
surfaces of the man-
dibular molars or t he
lingual surfaces of the
maxillary anterior teeth
are thinned, and we might suspect that the patient
has gastroesophageal reux disease or GERD. Yet
GERD is a mere symptom of other conditions, such
as obstructive sleep apnea. Perhaps one hasn’t made
that link before, but GERD is a very important
comorbidity of obstructive sleep apnea.
So dentists need to look for valuable hints to
recognize potential systemic problems in a patient.
ese are all clues that a talented practitioner will
recognize and piece together.
JCDA: Are there any systemic conditions for which
oral conditions are the precursor or may be the
early signs?
GS: Dentists may become aware of systemic condi-
tions in a patient well before a physician, primarily
because we see patients on a regular basis and have
the opportunity to update a patient’s health history.
e serial follow-up nature of dentistry places us in
an ideal observational position to be able to suggest
to people that there could be something else sys-
temically wrong with them.
Certainly with inammatory bowel disease, the
cobblestone changes in the buccal mucosa can pre-
cede the development of other symptoms and so
it is possible that one could notice this and then
nd out later that the patient in fact has Crohn’s
disease.
JCDA: Are there interesting avenues of research
being conducted that highlight the mouth as a
diagnostic window to the body?
GS: Karyotyping or scraping the buccal musoca was
previously used when we were thinking of the Barr
body. Sophisticated advances now allow researchers
to use salivary gland biopsies in the labial salivary
glands as a way to follow people who have such con-
ditions as Sjögren’s syndrome, to try to characterize
and prognosticate their disease. is is also true in
those patients who are treated for leukemia with a
bone marrow transplant and may over time develop
a condition called gra-versus-host disease.
Dr. Debora Matthews
“other health professIonals are begInnIng to connect the
mouth back to the body, whIch Is somethIng that we, as dental
professIonals and dentIsts, have known all along — that
oral health Is not separate from gener al health.”
214 JCDA • www.cda-adc.ca/jcda • April 2007, Vol. 73, No. 3 •
––– JCDA Panel Discussion –––
Returning to Dr. Tenenbaum’s thoughts on the in-
trinsic link between oral and general health, JCDA
talked with Dr. Chris McCulloch, a leading re-
searcher in the eld of cell biology, to learn about his
experiences straddling the boundary between “oral
health” and “systemic health” research.
JCDA: Dr. McCulloch, how did you become in-
volved in research on fundamental problems in cell
structure and function?
Dr. Chris McCulloch (CMc): I was always inter-
ested in biology going back to high school and
biological aspects of dentistry were also of some
interest. My periodontology training program at
Columbia University in New York was also very
biologically and experimentally oriented. at pro-
gram reinforced my interest in exploring funda-
mental questions in biology and how they might
relate to dentistry. Some of my teachers at the time
were involved in research linking the idea that gin-
gival crevicular uid enzymes might reect the
behaviour of neutrophils. If we could measure
neutrophil enzymes, we could use this as a way of
looking at how circulating neutrophils might con-
tribute to periodontal breakdown, not just in terms
of fundamental problems but also clinically.
Several years later I started my own lab and, in
collaboration with Jaro Sodek and Chris Overall
at the University of Toronto, I really started to
appreciate how systemic factors, particularly
neutrophil-derived enzymes that are found in the
periodontium, might have a signicant impact in
terms of periodontal health. is was very much
a 2-way street, as it wasn’t just systemic health
that was impacting the health of the periodontium.
Perhaps the health of a person’s mouth could im-
pact their overall health.
JCDA: How did your research evolve from an oral
health focus to examining more basic problems in
cell biology?
CMc: I decided to con-
centrate my research on
fundamental aspects of
the behaviour of certain
cells that are common to
the periodontium, but
which are also found in
heart muscle. I became
more interested in cardiac
physiology, so I started to
focus on how connective
tissue cells in heart muscle, called broblasts, con-
tribute to heart failure. In heart failure, if you have
some idea of what the cells are doing in terms of
their structure and function in, for example, the
development of brosis aer a heart attack, then
you are likely to have a better idea about how to
treat it.
I then became quite involved with the Ontario
Heart and Stroke Foundation, obtaining funding
and delivering lectures on the relationship between
oral disease and systemic disease and the import-
ance of the connective tissue matrix and connective
tissue cells in heart failure.
JCDA: Do you consider yourself an oral health re-
searcher or a basic science researcher?
CMc: e biology of the periodontium is part of
the biology of all human beings. ere should
be no disconnect here. While medicine and dent-
istry may have separate historical traditions, bio-
logically they focus on common issues. In terms
of my research, what is happening in certain
cells in the mouth or the heart is not dissimilar
because they’re all part of the same functional
organism.
When I collaborate with other researchers in
cell and molecular biology, they are primarily con-
cerned about whether or not I can contribute to
their research program and if there are sucient
common research interests between us to make
progress. I have never encountered criticism about
my training and background as a dentist. So any
perceived barriers between general health and oral
health research are, to me, quite articial.
JCDA asked the panellists for their thoughts on the
specic messages that individual practitioners and
the dental profession should convey about the oral
health–systemic health relationship.
JCDA: In your opinion, what messages should in-
dividual dentists provide to patients about the oral
health–systemic health connection?
Dr. George Sándor
“what occurs In the mouth has an effect on the musculoskeletal
system, the cardIovascular system, the respIratory system
and the dIgestIve system. oral health research should not
be vIewed In IsolatIon from other areas of health research
because these lInks are absolutely essentIal.”
Dr. Christopher McCulloch
“when a patIent shows Interest, I wIll dIscuss recent data
IndIcatIng that poorly controlled perIodontItIs may be part
of a more gener alIzed Inflammatory syndrome that affects
many tIssues, In addItIon to the perIodontIum.”
JC DA •JC DA • ww w.cda -adc .ca /jcd a • April 20 07, Vo l. 73, No. 3 • 215
––– JCDA Panel Discussion –––
DM: In terms of specic advice for people with
diabetes, we should advise these patients to visit the
dentist regularly for routine assessments of their
periodontal condition. Periodontal therapy should
be part of an overall therapy regimen, because we
know that diabetics who have good periodontal
maintenance have more stable blood sugar levels
than those who don’t.
CMc: When a patient shows interest, I will dis-
cuss recent data indicating that poorly controlled
periodontitis may be part of a more generalized
inammatory syndrome that aects many tissues,
in addition to the periodontium. In other words, if
you have increased inammation in your mouth,
you may have increased inammation elsewhere in
your body, such as atheromas. ese inammatory
lesions may be causally linked.
GS: It is the responsibility of not just individual
dentists but of dental organizations to promote the
knowledge and role of the mouth in terms of ideal
and optimum health. Because all health care profes-
sionals are in a preventive business, we have to pre-
vent disease at all levels, not just in the mouth but
disease that may be noticed in the mouths and then
occurring elsewhere.
JCDA: How can our dental organizations advocate
for greater understanding of the importance of oral
health to general health?
GS: I think that organized dentistry must promote
the view that conditions in the mouth do not occur
in isolation from conditions elsewhere in the body
and that systemic and oral diseases aren’t just re-
lated, they are inextricably linked.
DM: Other health professionals are beginning to
connect the mouth back to the body, which is some-
thing that we, as dental professionals and dentists,
have known all along — that oral health is not sep-
arate from general health. Dentistry has the right
message, and that is prevention. We do this well. We
have our patients come in on a regular recall basis
to help catch diseases early. I think prevention is a
message that other health care professionals could
take to heart.
CMc: Our organizations must continue to put re-
search on the agenda and make sure that it stays
on the agenda. Research needs to be a focus in
our organizations’ print and e-journals on a routine
basis, to ensure that research is placed front and
centre. e profession should also organize sym-
posia, venues in which colleagues can feel comfort-
able critiquing existing methods or raising issues
about diagnostic and treatment approaches where
we may not be doing particularly well. We need to
remember that a profession that does not renew it-
self scientically or does not generate its own stable
of investigators can move from being a profession to
being a trade.
GS: We must urge funding agencies, such as the
CIHR, to assess dental research in a more global
manner, because what occurs in the mouth has an
eect on the musculoskeletal system, the cardio-
vascular system, the respiratory system and the di-
gestive system. Oral health research should not be
viewed in isolation from other areas of health re-
search because these links are absolutely essential.
To bring the panel discussion to a close, JCDA asked
Dr. Tenenbaum to help summarize the panellists’
thoughts on the oral–systemic connection.
HT: When we consider all of the ideas that were
discussed here, it is clear to me that the true oral
health–systemic health connection is that oral and
systemic health are inseparable. We can try to justify
the delivery of dental treatment for periodontitis on
the basis of literature linking this disease to other
systemic diseases. However, we need to remember
that maintenance or achievement of optimal oral
health is a goal unto itself. As such, dental treat-
ment to achieve oral health requires no additional
justication!
Moreover, when one looks at the biological re-
search related to dental
physiology, we have be-
come more knowledgeable
about the physiological
and pathophysiological
mechanisms governing
other cells and tissues of
the body. is knowledge
can only lead to greater
insights regarding other
tissues and organ systems
Dr. George Sándor
“what occurs In the mouth has an effect on the musculoskeletal
system, the cardIovascular system, the respIratory system
and the dIgestIve system. oral health research should not
be vIewed In IsolatIon from other areas of health research
because these lInks are absolutely essentIal.”
216 JCDA • www.cda-adc.ca/jcda • April 2007, Vol. 73, No. 3 •
––– JCDA Panel Discussion –––
— once considered disparate — but from a bio-
logical perspective, evidently not so disparate from
oral cells and tissues. is knowledge base can only
lead to improvements in the understanding and
treatment of diseases, not only in the mouth, but
elsewhere.
It is this physiological and pathophysiological
continuum that connects tissues in the oral cavity to
other remote organ systems in both health and dis-
ease that has also been dened and recognized with
increasing clarity. is concept presages a more bio-
logical approach being taken by dentists regarding
diagnosis and management of oral diseases. I think
our discussion also shed some light on the contribu-
tion of the dental sciences and clinical dentistry to
the overall health and well-being of Canadians that
should not be underestimated. a
PANEL MEMbERS
Dr. Tenenbaum is associate dean of diagnostic and biological sci-
ences and professor of periodontology at the faculty of dentistry
at the University of Toronto. His major area of research involves
bone metabolism, using in vitro model systems to address ques-
tions of bone cell function and dierentiation. A secondary
research focus involves the study of temporomandibular joint
dysfunction and facial pain.
Dr. Matthews is head of the division of periodontics at Dalhousie
University. Some of her current research interests include an oral
health assessment for seniors in Nova Scotia. She is a leader in
evidence-based dentistry and teaches several courses at Dalhousie
in this discipline.
Dr. Sándor is professor and clinical director, graduate program
in oral and maxillofacial surgery and anesthesia, University of
Toronto and Mount Sinai Hospital; coordinator of pediatr ic oral
and maxillofacial surgery at e Hospital for Sick Children and
Bloorview Kids Rehab, Toronto, Ontario; and docent in oral and
maxillofacial surgery at the University of Oulu, Oulu, Finland.
His areas of research include bone regeneration and tissue engin-
eering; hyperbaric oxygen; congentital deformities, growth and
development; and pediatric dental implantology.
Dr. McCulloch is director of the Canadian Institutes of Health
Research Group in Matrix Dynamics and a professor in the fac-
ulty of dentistry at the University of Toronto. He was recently
named Canada Research Chair in Matrix Dynamics. His
research focuses on the regulation of connective tissue cells and
the signalling mechanisms that control their metabolism. To
read more about Dr. McCulloch’s research , please consult
“Integrating Dentists into the Biomedical Mainstream.” Alumni
Today, Vol. 25(1), Winter 2007, pp. 20-22.
Sean McNamara is writer/editor at the Canadian Dental
Association.
