Scientific american oral care

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Scientific american oral care

  1. 1. • Mouth - Body CONNECTIONS• The Facts and Fictions of INFLAMMATION• PREGNANCY and PERIODONTAL DISEASE• Linking DIABETES, OBESITY and INFECTION• Reflections from a SURGEON GENERAL• HEALTH POLICY of the Future• Blurring the DOCTOR-DENTIST BarrierA custom publication production in collaborationwith the Procter & Gamble Company
  2. 2. The mouth speaks for the body. We speak for the mouth. Crest and Oral-B. Today, the combined company of Crest and Oral-B exceeds more than Together for the first time. 100 years of innovation, information, and expertise. This combined heritage, Dedicated to uncovering coupled with a shared dedication to improving outcomes for dental all the links between professionals and patients alike, puts the new company of Crest and Oral-B at good oral health and the forefront of breakthrough science and oral health solutions. Crest and whole-body wellness. Oral-B are passionately committed to evolving the field of oral health and its relationship to whole-body wellness. Do we have all the answers today? No. Are we collecting evidence to suggest that there are some important links between oral and systemic health? Absolutely. Join us on the journey as we work to uncover the most critical information regarding the important role good oral health can play in achieving whole-body wellness.© 2006 P&G PGC-1713C OPAD06506 Dedicated to healthy lifesmiles
  3. 3. SCIENTIFIC AMERICAN PRESENTSORAL AND W HOLE BODY HEALTH INTRODUCTION » OUR MOUTHS, OURSELVES As the relationship between the mouth and the rest of the body becomes clearer, it is changing the way 3 dentists, doctors and patients view oral health. BY SHARON GUYNUP INVADERS AND THE BODY’S DEFENSES Gum disease illustrates how local infections may have systemic consequences. 6 BY PHILIP E. ROSS HEART HEALTH IN THE INFLAMMATION AGE Arterial plaques, once thought to be fatty deposits, are a result of the inflammatory process. 12 BY PETER LIBBY THE THREE-WAY STREETOR AL AND WHOLE BODY HE ALTHis published by S CIENTIFIC A MERICAN, Two decades of biomedical and dental detectiveINC ., 415 Madison Avenue, New York, work have linked obesity, diabetes and periodontalNY 10017-1111. Copyright © 2006 disease.by S CIENTIFIC A MERICAN, INC . All rightsreserved. No part of this issue maybe reproduced by any mechanical,photographic or electronic process,or in the form of a phonographic 18 BY ROBERT J. GENCOrecording, nor may it be stored in aretrieval system, transmitted or INTERVIEW »other wise copied for public orpr i v a te us e w i thou t w r i t ten BUZZ TALK WITHpermission of the publisher. MARJORIE K. JEFFCOATSubscription inquiries for The Dean of the University of Pennsylvania School ofS CIENTIFIC A MERICAN MAGAZINE:U.S. and Canada (800) 333-1199; 23 Dental Medicine on the facts and fiction surrounding oral health’s relationship to the rest of the body. CREDITOther (515) 248-7684b SCIENTIFIC AMERICAN PRESENTS: ORAL + WHOLE BODY HEALTH PROTCTOR & GAMBLE
  4. 4. A custom publication produced in collaboration with CREST and ORAL-B WHAT EVERY WOMAN NEEDS TO KNOW Growing evidence suggests that poor oral hygiene during pregnancy can adversely affect the health of newborns. BY STEVEN OFFENBACHER 24 AS THE BODY AGES When it comes to the complications of oral disease, the elderly are particularly vulnerable. BY FRANK A. SCANNAPIECO 30 INSIGHTS » ORAL HEALTH AROUND THE WORLD Maurizio Tonetti, an oral health professional who has worked in four different countries, offers some thoughts on the future of global oral health. 35 PUBLIC POLICY & ORAL HEALTH » A WHOLE NEW GAME Governments, insurers, clinicians and the public must all recognize the changing face of dental medicine. BY SHEILA RIGGS 36 INTERVIEW » DISCUSSION WITH DAVID SATCHER The former U.S. surgeon general reflects on his landmark report that put oral health on the national agenda and the policy steps that still need to be taken. 40CREDIT w w w. s c ia m . c o m SCIENTIFIC A MERIC A N c
  5. 5. RESEARCH SNAPSHOT » A custom publication produced in A NOVEL APPROACH TO collaboration with CREST & ORAL-B INFLAMMATIONPROJECT MANAGEMENT Understanding how the body “turns off” inflammationPublication and Media Director : may yield new treatments for periodontal disease 42 and other inflammatory conditions.Jeremy AbbateEditorial Director: Sharon GuynupFeatures Editor: Larry Katzenstein BY THOMAS E. VAN DYKEArt Director: Jeff Mellin & CHARLES N. SERHANIllustrators: Matt Collins, Tami Tolpa,Keith KasnotCustom Photography: John Soares PATH TO PREVENTION »Production Consultant: Richard Hunt MOUTHFUL OF BUGSCopy Editor: Michael Battaglia Pathogenic bacteria are a way of life.Research: Anna Kline So, too,must be brushing and flossing.BOARD OF ADVISERSRobert J. Genco: DistinguishedProfessor, Department of Oral Biology,School of Dental Medicine, StateUniversity of New York at Buffalo 46 BY ROBERT H. KAGANJim Beck: Distinguished Professor,Department of Dental Ecology, Schoolof Dentistry, The University of North INTERVIEW »Carolina at Chapel Hill THE ADA’S TAKEMarjorie K. Jeffcoat: Dean, University of How the American Dental Association, the world’sPennsylvania School of Dental Medicine leading dental organization, views the growing 49Steven Offenbacher: Director, Center forOral and Systemic Diseases, University connections between a healthy mouth and a healthyof North Carolina at Chapel Hill body — a conversation with Daniel M. Meyer.Maurizio Tonetti: Chair, Division ofPeriodontology, University ofConnecticut School of Dental MedicineThomas E. Van Dyke: Professor,Department of Periodontology andOral Biology, Boston UniversityGoldman School of Dental Medicine A Message from the A MERICAN A CADEMY OF P ERIODONTOLOGYSCIENTIFIC AMERICANEDITORS & PROJECT STAFF THE AMERICAN ACADEMY OF PERIODONTOLOGY (AAP) congratulates Procter & GambleEditor In Chief: John Rennie Professional Oral Health, Scientific American and all of the contributors to this specialExecutive Editor: Mariette DiChristinaManaging Editor: Ricki L. Rusting supplement for providing in-depth and balanced information on the association betweenNews Editor: Philip M. Yam periodontal diseases and general health conditions.Special Projects Editor: Gary StixSenior Editor: Michelle Press The AAP has been a leader in tracking periodontal and systemic research for over a decade.Editors: Mark Alpert, Steven Ashley, The research results to date have been promising, and the prospect that periodontalGraham P. Collins, Steve Mirsky,George Musser, Christine Soares treatment may significantly improve general health outcomes is exciting. However, there isArt Director: Ed Bell still a great deal to learn about the impact of periodontal infection and infl ammation onAssociate Publisher, Production: general health. Additional research into these complex associations is essential if patientsWilliam Sherman are to reap the benefi ts of improved health.Production Manager: Christina HippeliPrepress and Quality Manager: Silvia Given the potential impact on diabetes, pre-term low birthweight, cardiovascular diseaseDe Santis and other conditions, we believe this research merits the investment and should be prioritizedDirector of Ancillary Products: DianeMcGarvey by the National Institutes of Health and other funding agencies.Associate Publisher, Circulation: The Academy and its member periodontists are proud to collaborate to advance oral andSimon AroninCirculation Director: Christian Dorbandt systemic health. Readers are encouraged to visit www.perio.org for more information aboutGeneral Manager: Michael Florek periodontists and periodontal health.Business Manager: Marie MaherPresident and Chief Executive Officer:Gretchen G. Teichgraeber — KENNETH A. KREBS, D.M.D.Vice President and Managing Director, CREDITInternational: Dean Sanderson President, American Academy of PeriodontologyVice President: Frances Newburgd SCIENTIFIC AMERICAN PRESENTS: ORAL + WHOLE BODY HEALTH PROTCTOR & GAMBLE
  6. 6. INTRODUCTIONOUR MOUTHS, OURSELVES As the interrelationship between the mouth and the rest of the body becomes clearer, dental professionals, doctors and patients will need to rethink the term “oral health” BY SHARON GUYNUP ORAL AND WHOLE BODY HEALTH 3
  7. 7. S I N C E T I M E I M M E M O R I A L , people have struggled to maintain adequate oralhealth. As far back as a.d. 250, Kemetic Egyptians used myrrh and other antiseptic herbs to treat infected gums. The Nubiansthat dwelt in the Nile River valley two centuries later drank beer as a palliative for unhealthy teeth; it may have worked well,as it was brewed from grain contaminated with the same bacteria that produces tetracycline. Lengthening teeth and receding gums have historically “oral-systemic link” emerges almost daily. For example, inbeen considered a consequence of surviving into adulthood. May 2006 it was announced at an American Society for Mi-(In his 1852 novel The History of Henry Esmond, Esq., Wil- crobiology meeting that researchers have identified genes inliam Thackary used the expression “long in the tooth” to certain oral bacteria that allow the organisms to invade anddescribe a middle-aged person.) The few teeth that didn’t de- infect human arterial cells. This certainly expands to thecay in youth usually loosened with the passing years, as the discussion of the possible biologic pathways that might linktissues supporting them were eroded by periodontal disease. the mouth and the heart (or other parts of the body). Addi-Those teeth ultimately fell out. tionally, this year will see the results of two major studies Today, people are living longer, and gum disease has sup- examining the relationship between oral disease and preg-planted tooth decay as the most common cause of tooth loss nancy complications in expectant mothers.in adults. The disease affects about 80 percent of Americans So what exactly is the connection between what happensover age 65, according to the American Dental Association. in your mouth and your overall health? Some of the millionsAt the turn of the last millennium, then–U.S. surgeon gen- of bacteria that lurk in our mouths (numbering more than alleral David Satcher called periodontal disease the “silent the cells in our bodies) are the primary culprits—along withepidemic” in his landmark report, Oral Health in America. the subsequent inflammation they cause. These microrgan-Given the state of public health, good oral hygiene may prove isms form complex colonies of sticky plaque. This tenaciousto be more critical than just preserving your smile. A grow- plaque — what microbiologists call a “biofi lm” — is com-ing body of research suggests that periodontal disease may posed of durable, coral reef–like structures, building up at theplay a role in a variety of systemic health problems as wide gum line and in between teeth.ranging as diabetes, respiratory illness, pregnancy complica- Some of the approximately 500 species of bacteria in yourtions, and heart disease. mouth are not innocuous flora. They cause gingivitis, infect- It is this body of research—and the attendant health pol- ing gums. Your immune system steps in to fight these invad-icy implications it engenders—that is the subject of this cus- ers—gums become inflamed, and may bleed when you brush.tom publication from Scien-tific American, Oral andWhole Body Health, pro- The fields of dentistry and medicine have traditionallyduced with the generous sup-port of the Procter & Gam- been worlds apart. But in light of the growing evidenceble Company. Here we pres- pointing to links between oral and whole body health, thisent, for the benefit of both separation of disciplines is slowly beginning to change.health professionals and pa-tients, the latest pieces in theever-growing puzzle of oral disease’s connection to systemic Interestingly, if this same type of infection appeared on a per-health. You’ll hear from some of the pioneering researchers son’s arm or another body part, they would no doubt go run-themselves about their ongoing explorations into the mouth- ning to the doctor for treatment—but bleeding, tender gumsbody relationship. are often ignored. Like any new area of scientific inquiry, some data paint a Untreated, this tenderness progresses into full-blown peri-very clear picture while other results are still inconclusive. odontitis, and here the immune system shows its dark side.Several studies, for example, have found that blood-sugar This simmering inflammation ulcerates gums and summarilylevels in diabetics with periodontal disease were significant- destroys the soft tissue and bone that anchors your teeth. Itly reduced when the patients’ gum disease was treated. Oth- also sends inflammatory substances throughout the body.ers, like the ones examining the connection between peri- Researchers are discovering that out-of-control inflamma-odontal disease and heart conditions, have not yet uncovered tion may prove to be the engine that drives an ever-growinga defi nitive causal relationship. But new information on this list of greatly feared, chronic illnesses from clogged arteries4 ORAL AND WHOLE BODY HEALTH
  8. 8. and heart attacks to arthritis and cancer. This inflam- es on their Web site, mation link is just one of a number of hypotheses ex- warning: “if you or plaining how chronic oral infection may trigger or someone you know intensify systemic diseases. had periodontal dis- Another concern is that the microbial ecosystem in ease, diagnosed or your mouth doesn’t just stay there. Stealthy, virulent undiagnosed, and ei- bacteria overgrow in inflamed gum tissues; with each ther ignored or treat- bite of food or stroke of a toothbrush, some of those ed unsuccessfully, microbes can seep into your bloodstream, traveling to before or during the distant parts of your body. The question is: can they set same time as any of the up shop elsewhere and cause harm? It is known that some mentioned systemic dis- of these bad bugs, when inhaled, can cause pneumonia, par- eases, you may be eligible ticularly in the elderly. Some are also able to move through arter- for damages caused by these ies to the uterus and have been found in the placenta. systemic diseases.” Although BUGS WITH STAYING POWER: an extreme example, it embod- clearly the mouth is in many ways the “gateway” to the Once thought to be a mere ies the confusion and hype sur- rest of the body. However, this connection is often overlooked. congregation of pathogens, rounding this topic and under- dental plaque is now known to In the U.S., the fields of dentistry and medicine have tradition- be a dynamic – and tenacious – scores the need for objective, ally been worlds apart. But in light of the growing evidence microbiological community credible analysis. And it ig- pointing to links between oral and whole body health, this called a biofilm. nores the fact that oral disease separation of disciplines is slowly beginning to break down. is complex. The notion that dentists care for only gums and teeth, while For example, changing hormone levels can cause flare-ups doctors look after everything else is being rethought. in women during pregnancy and while premenstrual—or in There is a dawning realization that often it is a dentist or perio- those taking oral contraceptives. Other medications can also dontist who first discovers a larger health problem, because of make gums more susceptible to infection, including antihis- what they see in a patient’s mouth—and that doctors need to look tamines, antidepressants, cancer drugs, steroids, and espe- at more than the tonsils when a patient opens wide and says “ah.” cially those that cause “dry mouth,” disrupting the mouth’sP R E V I O U S P A G E P H O T O : J O H N S O A R E S M O U T H I M A G E S : C L I P A R T. C O M C O L L A G E I L L U S T R A T I O N : J E F F M E L L I N For example, diabetics tend to develop periodontal disease at three bacterial ecosystem. Genetic, microbial, immunological and to four times the rate of nondiabetics. If a dental professional sees environmental factors influence both the risk and progression gum inflammation in someone who brushes and flosses regu- of infection. For example, the American Academy of Peri- larly, they need to ask, “Have you checked your blood sugar odontology says that perhaps one third of Americans may be lately?” Or, conversely, the doctor of a patient with uncontrolled genetically susceptible—making them up to six times more blood sugar may need to refer them to a dental professional. likely to develop periodontal disease. It could be that in some There is already a ripple effect in some sectors of the insur- cases these same factors or susceptibility might independent- ance industry. Some insurers are finding it more cost-effective ly cause harm elsewhere in the body, creating a mere illusion to include periodontal treatment among covered services for of oral-systemic causality. diabetics and pregnant women. But if additional research so- Of course, one of the most important differences between lidifies the links between gum disease and other chronic ill- periodontal disease and other systemic conditions is that the nesses, sweeping changes will be needed to provide access to former has a known cause and is quite treatable. Dental profes- care. This will be crucial for the segments of society—the poor sionals should never lose sight of the fact that they are address- and the elderly—who are most at risk for oral disease as well as ing a disease that significantly contributes to disability and a conditions such as heart disease and diabetes. It is a huge public lack of well-being in the population. This fact alone makes it health issue: periodontal treatment and prevention can cost important to treat this condition, regardless of whether it might between $100 and $1,000 annually per patient. contribute to other serious illnesses. And although no one Over the past few years, newspapers, magazines and oth- should overstate the oral-systemic link, proffers Robert Genco, er national media outlets have hyped numerous stories about a professor of oral medicine and microbiology at the Univer- the possible systemic health risks of periodontal disease as sity at Buffalo, no one should underestimate what can happen well as inflammation’s general link to a broad range of dis- if it’s ignored, either. While the mouth’s relationship to the rest eases. Some articles have greatly exaggerated or oversimpli- of the body will certainly be a matter of public health, of patient fied the connection, enough so that the expression “floss or awareness and of the changing roles among caregivers, it will die” has become a standing joke among researchers. first and foremost be a matter of science. • Even some opportunistic law fi rms have jumped on the bandwagon. One in Arizona solicits potential malpractice cas- SHARON GUYNUP is editorial director of Oral and Whole Body Health. ORAL AND WHOLE BODY HEALTH 5
  9. 9. >>Gum disease illustrates how local infections may have systemic consequencesINVADERS& THE BODY’S DEFENSES BY PHILIP E. ROSS IF EVER THERE WAS A MAGIC BULLET —a drug so discriminating that it attacked microbes while sparing healthy tissue— it would be the monoclonal antibody, a human-tuned form of an immune molecule honed by eons of natural selection. Yet, as the world learned this spring, when such an antibody nearly ic effects are nowhere better illustrated than killed several subjects in a British clinical in chronic gum disease. Although it origi- trial, even these drugs can cause serious side nates in a bacterial assault, some two thirds effects. No one should have been too sur- of the damage is caused by the inflammatory prised; the natural immune response also response to the perceived invader. What is causes damage, which is why it fully mobi- worse, inflammation somehow communi- lizes—in a process called inflammation— cates itself to distant points, explaining the only when the enemy is at the gates. possible association of gum disease with oth- In recent years, a lot of media attention er conditions: adult-onset (or type 2) diabe- has been lavished upon the process of inflam- tes, premature birth, stroke and cardiovascu- mation (including a cover story in Time mag- lar disease. However infection travels from azine on this “silent killer”) as researchers the mouth to infl ame distant organs, it is continue to uncover evidence linking it with clear that it turns the body against itself. In other serious diseases. Whether or not in- the words of the cartoon character Pogo, >> flammation turns out to be the “holy grail” of “We have met the enemy and he is us.” medicine is yet to be seen. But inflammation’s Only a handful of the more than 500 spe- problem of friendly fi re and potential system- cies of bacteria that live in the mouth are6 ORAL AND WHOLE BODY HEALTH
  10. 10. S INFECTION AND INFLAMMATION in the mouth have been linked to a variety of systemic conditions, including pregnancy complications, type 2 diabetes, heart disease and stroke. While recent national media coverage spotlighting inflammation has spawned much interest in the JOHN SOARES topic, more research is needed to uncover exactly how infection and inflammation affect the body. ORAL AND WHOLE BODY HEALTH 7
  11. 11. MOUTH A PRIME LOCATION The hard, non-shedding surface of the teeth and the nutrient-INVADERS rich, oxygen-poor environment of the mouth provide ideal conditions for the growth of oral bacteria. They easily attach themselves to the tooth and gum. Of the over 500The Progression of microorganisms that live in dental plaque, only a handful havePeriodontal Disease been implicated in gum disease.implicated in gum disease. They are par- dead and dying neutrophils, and any the ligaments that anchor teeth in theirticularly hard to eradicate because they cellular detritus that may litter the bat- sockets, loosening them until they at lastform biofilms: tough, many layered, tlefield. Meanwhile, the macrophages fall out. Nowadays this happens less fre-mineral encrusted communities. Hud- secrete fatty acids and interleukin-1 quently; the patient notices the bleedingdling in the deepest layers are the oxygen- (IL-1), a primary regulator of infl am- and goes to a dentist. The dentist or den-shunning, or anaerobic, bacteria that ap- matory and immune responses, as well tal hygienist scrapes away inflammation-pear to cause the most damage. as tumor necrosis factor alpha (TNF ), riddled material and treats the infection When bacteria come in contact with a protein that heightens inflammation. with antibiotics. Treatment, however,gums, they secrete toxins that break The resulting mayhem may be likened cannot prevent the influx of bacteria.down gum lining, creating a tiny ulcer. to urban warfare, with immune sol- The disease will recur if the patient doesThe body’s bloodhounds, the neutro- diers running from house to house, not stick to a rigorous routine of brush-phil cells, then attack these invaders. If tossing in grenades, spraying rooms ing, flossing, rinsing and dental clean-they keep the biofi lm at bay, the battle with machine-gun fi re, all before ask- ings. And although the damage in peri-reaches a standoff, termed gingivitis. If, ing who is friend and who is foe. No odontal disease is primarily the result ofhowever, the bacteria continue to ad- wonder the tissue breaks down. The the inflammatory process, it can only bevance into the gums, the immune sys- ulcers sink deeper into the gum, creat- prevented or treated by addressing thetem signals a higher state of alert, mo- ing a “periodontal pocket”; full-blown bacterial biofilm that is infecting thebilizing macrophages (Greek for “big periodontitis begins. gums. What is worse, the chance of earlyeaters”). These white blood cells swal- If the disease is allowed to progress, detection is lessened in those who arelow bacteria, along with the gorged, the advancing inflammation eats away most vulnerable—smokers. Just as to-8 ORAL AND WHOLE BODY HEALTH
  12. 12. TENACIOUS BUGS A HEATED STRUGGLE Oral bacteria are particularly hard to eradicate because they form Continued defensive strikes by the immune system heighten tough, many-layered, mineral-encrusted communities, known as inflammation as specialized white blood cells (macrophages, biofilms. If untreated, these biofilms become lodged in the gingival as well as others) secrete inflammatory substances. This crevices around the tooth. The immune system launches a defensive intense inflammation can ultimately break down gum tissue, strike against these bacterial invaders by dispatching neutrophils. creating a periodontal pocket — the beginning of full-blown The first signs of inflammation (redness, swelling) begin to appear. periodontal disease. bacco smoke irritates the gums, height- neutrophils have trouble homing in on tomb fat in situ, creating atherosclerot- ening inflammation, it also tends to mask bacteria, showering them with chemical ic plaque. This buildup, combined with telltale bleeding. grenades called superoxides. “But instead inflammation, fattens the arterial wall, Other factors that predispose people of destroying bacteria, they destroy the gradually restricting blood flow to tis- to gum disease include bad oral hygiene periodontal ligament that ties the tooth to sues. Sometimes, for reasons that are and an unlucky bequeathal of genes. the jaw,” says Charles N. Serhan, profes- not well understood, the thin layer of One very invasive form of periodontal sor of anesthesiology at Harvard Medical tissue covering the plaque ruptures, disease is found in just 0.1 percent of School. “It’s like rheumatoid arthritis, an spurring clots to form in a matter of Americans, a distribution that indicates autoimmune disease where a lot of the minutes, often triggering a heart attack a genetic component. People with these degradation of the synovium [the lining of or stroke. This is why the most com- and other predisposing genes must work the joints] is done by neutrophils.” Serhan mon fi rst symptom of heart disease is extra hard to care not only for their is looking for ways to shut down this ex- sudden death. teeth but even for the artificial implants cessive immune response. If infection in the gums not only pre- that may replace those teeth. Periodon- When inflammation strikes sites far cedes inflammation in the arteries, but tal disease can strike the tissues sur- from the gums, it progresses there much encourages it, the question is how does rounding implants as well. as it does in the mouth. In the lining of it happen. One theory holds that bacte- Genetic variation is of particular in- the heart’s arterial wall, for instance, ria are the primary vehicles in commu-M AT T COLLINS terest because it may illuminate the mech- macrophages engulf whatever detritus nicating disease; another lays the blame anisms that underlie all varieties of peri- they find, including fatty particles. on proinflammatory chemicals that leak odontal disease. In one invasive form, When the macrophages die, they en- out of the gums and into the blood- ORAL AND WHOLE BODY HEALTH 9
  13. 13. stream. Direct inflammation currently valve. What if a similar weakness ex- sidered innocuous. Yet critics of theholds sway, particularly in the popular ists in the arterial lining? bacterial-cause theory point out thatpress. Still, there is evidence supporting Researchers have, in fact, found oral bacteria survive poorly in theboth theories, and each may explain traces of oral bacteria in arterial plaque. bloodstream. They also note that proin-part of the problem. Yet as critics of the infection theory flammatory chemicals demonstrably Oral bacteria can get into the blood- point out, the method they used to iden- leak from the gums into the blood-stream. Robert Genco, a professor of tify the bacteria—a highly potent DNA stream, adding to the body’s inflamma-oral medicine and microbiology at the amplification tool—cannot tell how tory burden. In a test tube, proinflam-University at Buffalo, took moment-by- many bacteria were present in the matory agents from one group of cellsmoment blood tests in healthy patients plaque or whether any of them were can spark a response in another group.undergoing routine teeth cleaning. The alive when they entered it. Injecting proinfl ammatories into ani-bacterial count spiked when cleaning be- Paul Ewald, an evolutionary biolo- mals also produces such a response.gan, then fell back to normal less than a gist at the University of Louisville, has Some argue that these chemicals aloneminute after it was over—that is how fast been a leading advocate of the role of can explain the association of gum dis-the body’s immune system rousts such infectious agents in chronic illnesses. ease and systemic illness.invaders. Yet in people with periodontal He argues that gum disease fits into the Here is how it might play out. Imag-disease, such bacterial inundations of the evolutionary model he has devised be- ine that there is some small irritation inblood occur every time a loosened tooth cause it is chronic, widespread and of the wall of the coronary artery, per-moves in its socket, providing many op- great antiquity, and therefore cannot be haps the result of chemicals absorbedportunities for a stray bacterium to relo- simply the result of defective genes. from cigarette smoke or car exhaust. Ifcate to some distant location. “If it were just a case of the immune the overall inflammatory burden is low, Oral bacteria, once established else- system going haywire, you’d think that then perhaps these sites will remainwhere in the body, are bad news. Genco natural selection would have weeded it quiescent. If, however, proinfl amma-injected Porphymonas gingivalis, a out,” he says. “But if you are looking at tory chemicals have leached from themain culprit in periodontal disease, un- actual combat between the immune sys- periodontal pocket into the blood-der the skin of rodents and found that it tem and [an] infectious agent, you’d ex- stream, it might heighten local inflam- mation in the artery, beginning the process of atherosclerosis.If infection in the gums not only precedes How do the two theories stack up? Itinflammation in the arteries, but encourages it, is not easy to say from the evidence nowthe question is how does it happen? in hand, which comes mainly from ob- serving correlations between gum dis- ease and other diseases; either or both ofinvariably produced fatal infections. “It pect it to be an evolutionary arms race, the proposed mechanisms could be re-causes gross necrosis of skin and under- one that would never stabilize.” That sponsible. Take the evidence linkinglying tissue; if you inject into the belly, same arms race would have tuned the periodontal disease with prematurethe intestines will be exposed,” he says. bacteria to a high pitch of virulence and birth, which could be caused by the in-A rare, analogous condition has been invasiveness, hence their ferocious be- fection reaching the uterus or, alterna-seen in humans, in which a dental infec- havior when ensconced in another part tively, by the release into the bloodstreamtion spreads down the neck to the area of the body. of such proinflammatories as prostaglan-surrounding the carotid artery, where it Biologists are now investigating the din E2, a drug used by obstetricians todigests tissue. possibility that many chronic illnesses, induce labor. There is also evidence that Perhaps the most persuasive exam- once attributed to other causes, may in oral disease destabilizes blood sugar con-ple of a secondary infection from oral fact stem from infection. Several strik- trol in diabetic patients, although thesources comes from patients who have ing examples have been demonstrated mechanism remains unclear. It is knownmitral valve heart defects. Such pa- in the past two decades: Stomach ulcers, that high blood sugar contributes to gumtients are warned to take antibiotics long attributed to stress, spicy food and disease and that all kinds of stress badlybefore their dental appointments so genes, turn out to derive, almost always, impact diabetic control. Periodontal dis-that tooth cleaning will not send bac- from the bacterium Helicobacter pylori. ease may put stress on the body byteria to infect or inflame the valve, Cervical cancer, it is now known, can spreading bacteria, increasing the in-which could destroy it or produce clots develop only in women who have been flammatory burden, or both.that might block arteries. The critical infected by certain varieties of the hu- So, too, many treatments whose suc-element here is the vulnerability of the man papillomavirus (HPV), long con- cess may seem to confi rm one theory or10 ORAL AND WHOLE BODY HEALTH
  14. 14. INFLAMMATORY MOLECULES produced locally in tissue can get into the bloodstream and travel throughout the body. FIGHTING INVADERS The inflammation-causing bacteria can also infect blood and travel to distant points. THE IMMUNE SYSTEM INCLUDES, among other components, antimicrobial molecules and various phagocytes (cells that ingest and destroy pathogens). These cells, such as dendritic cells and macrophages, also activate an inflammatory response, secreting proteins called cytokines that trigger an influx of more defensive cells from the blood. another turn out to be hard to interpret. We need interventionist studies to learn Genco notes that “the insurance com- Aspirin, an anti-inflammatory, is used whether treating oral disease unmistak- panies are driven by economics, and to reduce the risk of heart attack, but ably shows a preventative benefit against even though the science isn’t absolutely again, no one can say that this proves heart disease. Such trials are needed to there yet, they are taking action.” that inflammation, pure and simple, is justify any public investment in such The smart money, therefore, is bet- the culprit. It could be that aspirin mere- treatment, and several are now planned ting on healthy gums. To keep them that ly limits clotting. and in line for funding. way, there are no magic bullets, no What is needed are large clinical tri- In the meantime, insurance compa- chemicals that can be added to drinking als in which patients are divided, at ran- nies—which are used to basing policies water, as fluoride was added to stave off dom, into two groups: one that gets on purely actuarial data—are respond- tooth cavities. There is no substitute for treatment for periodontal disease, an- ing. This year, Aetna Dental announced brushing, flossing and regular dental other that gets a placebo. Two such stud- the results of a study of policyholders visits. It should be easier to justify than ies are trying to determine whether such that had both dental and health insur- in the past, for the dentist’s or hygien- treatment alleviates the risk of prema- ance. It showed that treating periodon- ist’s ministrations may turn out to pro- ture birth in women with gum disease. tal disease in heart patients lowered the tect not only your teeth, but, quite pos- Another is testing whether antibiotic total cost of treating both conditions. sibly, the rest of you as well. • treatment can alleviate heart disease. Yet,TA MI TOLPA even here, one must beware of the pos- PHILIP E. ROSS, a former S CIENTIFIC A MERICAN contributing editor, is currently the online sibility that antibiotics themselves may editor of IEEE Spectrum, the magazine of the Institute of Electrical and Electronic exert a subtle anti-inflammatory effect. Engineers. He has written for Forbes and Red Herring. ORAL AND WHOLE BODY HEALTH 11
  15. 15. It is clear that inflammation is linked to heart disease, andthat one of the body’s most common sources of inflammationis periodontal disease. Does poor oral health contribute toheart disease risk? Although the jury is still out whilescientists investigate this link, here is what we know aboutinflammation’s role in atherosclerosis. | BY PETER LIBBYHeartHealth INFLAMMATION AGE INTHEO N L Y A D E C A D E A G O, most physicians would have confidently described sometimes fail. It also highlights the need for better prevention, detectionatherosclerosis as a plumbing problem: Fat-laden gunk gradually builds up on and treatment. In industrialized na- tions, deaths from heart attacks andartery walls. If a deposit (plaque) grows large enough, it closes off an affected strokes exceed those from cancer—and they are also becoming more prevalent“pipe,” preventing blood flow. Eventually, Such research has established in- in developing countries.the blood-starved tissue dies. If that flammation’s key role in atherosclerosis.happens in the heart or the brain, a heart This process—the same one that causes IGNITING TROUBLEattack or stroke occurs. infected cuts to become swollen, hot we know that inflammation symp- Few believe that tidy explanation and painful—underlies everything from toms reflect a pitched struggle on a mi-anymore. Twenty years of research show the creation of plaques to their growth croscopic battlefield. After sensingthat arteries bear little resemblance to and rupture. (rightly or wrongly) a microbial inva-pipes. They contain living cells that When microbes invade, inflamma- sion, certain types of white bloodcommunicate with one another and tion (literally meaning “on fi re”) fights cells—the immune system’s frontlinetheir environment. They also partici- infection. But with atherosclerosis, in- warriors—convene in the threatenedpate in the development of the fatty de- fl ammation proves harmful; our own tissue. There they secrete chemicals toposits that grow within vessel walls— defenses bombard us with friendly fire, limit infection: oxidants that damagefew which actually shrink vessels to a just as they do in lupus and other auto- invaders and signaling molecules (in-pinpoint. Most heart attacks and many immune disorders. This revised picture cluding proteins called cytokines) that M AT T COLLINSstrokes stem from interior plaques that resolves two disturbing mysteries: why orchestrate the activities of defensiverupture suddenly, spawning a blood clot many heart attacks strike without warn- cells. Their presence in tissue signifiesthat blocks blood flow. ing and why preventative therapies an inflammatory response. >>12 ORAL AND WHOLE BODY HEALTH
  16. 16. CROSS-SECTIONOF HEALTHYCORONARY INFLAMMATION’S MANY ROLESARTERY INFLAMMATION—a central player in atherosclerosis—occurs when white blood cells, the body’s first line of defense against infec-Blood channel tion, invade and become active in tissue. These diagrams depict atherosclerotic plaque growth in a coronaryIntima artery; the close-ups highlight some inflam- matory processes triggered by elevatedMedia low-density lipoprotein (LDL) in the blood.Adventitia LOL T cell Endothelial 1 Monocyte Adhesion cell Scavenger Foam 2 molecule receptor cell 3 Blood channel INTIMA Modified LOL Chemokine Plaque Thrombus 4 5 Microphage Inflammatory Elastic tissue mediators MEDIA Smooth muscle cellsBIRTH OF A PLAQUE PLAQUE PROGRESSION1 Excess LDL accumulates in ar tery walls, undergoing chemical changes. ModifiedLDLs stimulate endothelial cells todisplay adhesion molecules, which 2 Monocytes mature into active macrophages in the intima; with T cells, they produce inflammatory mediators, including cytokines that carr y signals 3 The macrophages display “scavenger receptors” to help ingest modif ied LDLs; macrophages feast on them, filling with frothy, fatty droplets. These 4 Inflammatory molecules trigger further plaque growth. A fibrous cap develops over the lipid core when the molecules induce smooth musclecapture circulating monocytes (key between immune system cells and “foam cells” combine with T cells, cells to migrate to the intima surface,players in inflammation) and T cells factors that promote cell division. comprising the fatty streak—early multiplying and producing a tough,(immune cells). Endothelial cells atherosclerotic plaque. fibrous matrix that glues cellsalso secrete “chemokines,” luring together. The cap makes the plaquesnared cells into the intima. larger and walls it off from the blood. Cholesterol studies on both animals As LDLs accumulate, their lipids mature into active macrophages, readyand cultured cells have elaborated in- oxidize—a corrosive process similar to to unleash their weapons against theflammation’s role in atherosclerosis. Sci- the one that rusts pipes. Cells in the body’s enemies. These warriors set aboutentists have long known that although blood vessel wall react to these changes clearing perceived invaders from vesselwe need cholesterol, excessive amounts by calling for reinforcements from the walls. Scavenger receptor molecules cap-clog arteries. But until recently, no one body’s defense system. Adhesion mole- ture modified LDL particles and helpknew how this happened. Low-density cules on the endothelial cells that line macrophages “eat” them—until they’relipoprotein (LDL)—also known as bad vessels latch like Velcro onto mono- so full of fatty droplets that they lookcholesterol—is composed of fatty mol- cytes, inflammatory cells that normally foamy under a microscope, giving themecules (lipids) and protein. Its job: trans- circulate in the blood, attaching them to their “foam cell” nickname.port cholesterol (another lipid) from its artery walls. Endothelial and smooth T lymphocytes (a type of white bloodsource in the liver and intestines to other muscle cells inside vessels then secrete cell) also attach themselves to arteryorgans. The trouble begins when LDLs chemokines—chemicals that attract walls, releasing cytokines that intensifyfrom the blood collect in the intima, the monocytes. Much as hounds track the inflammation. The fi rst visible athero-interior wall of an artery. At low concen- scent of their prey, more monocytes fol- sclerotic lesion, a yellow “fatty streak,” KEITH K A SNOTtrations in the blood, LDLs can pass in low the chemical trail into the intima. is a mix of foamy macrophages and Tand out of the intima; in excess, LDLs Stimulated by chemokines and other lymphocytes. These lesions are a precur-become stuck in the cell matrix. substances, the monocytes multiply and sor of the complex plaques that later dis-14 ORAL AND WHOLE BODY HEALTH
  17. 17. PLAQUE RUPTURE sel surface. Once there, they form a fi- channel. This also explains why bypass5 Foam cells secr ete inf lammator y subs tances that weaken the cap, digesting matrix molecules and damagingsmooth muscle cells that normally repair it.Foam cells may produce tissue factor, a potent brous covering over the original plaque. Underneath this cap, some foam cells die, releasing their load of lipids. surgery or therapies such as angioplasty or stents that widen obstructed arteries can ease angina—yet often fail to pre- Atherosclerotic plaques usually ex- vent a heart attack. Even when blockedclot-promoter. If the plaque ruptures, a clotforms. A large clot can halt blood fl ow to the pand outward, not inward to block an arteries are treated, they often clog upheart, causing a heart attack—the death of artery’s blood-carrying channel. When again fairly quickly—it seems that thecardiac tissue. they do push in, blood flow to tissues is treatment itself elicits a robust inflam- restricted, especially when arteries matory response. Thrombus would normally expand. During exer- Matrix-degrading enzyme cise or stress, blood flow through a com- BEYOND BAD CHOLESTEROL Cytokines that disrupt smooth promised heart artery fails to meet the several other atherosclerosis risk fac- muscle cells Fibrous increased demand. This causes angina tors exhibit intriguing inflammatory fea- cap pectoris, a feeling of tightness or pres- tures: diabetes, for instance, elevates sure usually under the breastbone. Nar- blood sugar levels, which can enhance rowing in other arteries can cause pain- LDL’s inflammatory properties. Smoking ful cramping of the calves or buttocks causes oxidants to form, possibly hasten- during exertion. ing LDL oxidation—and fostering arte- rial inflammation even in people with CAUSING CRISES average LDL levels. Obesity contributes only about 15 percent of heart at- to diabetes and vascular inflammation. tacks are caused by large plaques that Conversely, high-density lipoprotein block arteries. Autopsies have shown (HDL) seems beneficial; as levels of this that most attacks occur after a plaque’s “good cholesterol” decline, the likeli- fibrous cap ruptures, prompting a blood hood of suffering a heart attack goes up. clot to develop over the break. Inflamma- HDL may achieve its beneficial effects tion makes the cap vulnerable. My labo- in part by reducing inflammation, be- ratory found that when stimulated by cause along with cholesterol, HDL inflammatory chemicals, macrophages transports antioxidant enzymes that secrete enzymes that degrade a cap’s break down oxidized lipids. strong collagen fibers and stop smooth Given inflammation’s usual respon-CUTAWAY VIEW OF ARTERYAFFLICTED BY ATHEROSCLEROSIS muscle cells from extruding fresh colla- sibility in the body—blocking and elim- gen to repair and maintain it. inating infectious agents—biologists Clots form when blood seeps have wondered whether arterial infec- through a fi ssure in a cap and coagu- tions might contribute to inflammationfigure arteries. Many Americans begin lates. Although our bodies produce sub- in the arteries. Recent studies suggestplaque buildup as early as their teens. stances that can prevent or degrade that atherosclerosis can develop in the blood clots, infl amed plaques release absence of infection. However, circum-FUELING PLAQUE GROWTH chemicals that impede this clot-busting stantial evidence suggests that certainwhen an inflammatory response in, machinery. If a clot does clear naturally microorganisms, such as herpes virusessay, a scraped knee successfully blocks or with medication, the healing process or the bacterium Chlamydia pneumoni-infection, macrophages release molecules may kick in once again, restoring the ae could induce or aggravate atheroscle-that promote healing. A “healing” pro- cap but also enlarging the plaque by rosis. C. pneumoniae appears in manycess is also part of the chronic, low-level forming scar tissue. Considerable evi- atherosclerotic plaques—and can trig-inflammation that operates in athero- dence suggests that plaques grow in fits ger inflammatory responses.sclerosis. But instead of restoring artery and starts as inflammation comes and Infections might also act from a dis-walls, the process perversely remodels goes and as clots emerge and dissolve. tance, in an “echo effect.” When thethem, generating a bigger plaque. This new picture of atherosclerosis body fights infections, inflammatory me- Recently, biologists have learned explains why many heart attacks seem diators can escape into the blood andthat both macrophages and cells within to come from out of the blue. Plaques travel to distant sites. Because the mouthan inflamed vessel wall secrete sub- that rupture may not protrude very far can be a source of chronic infection, re-stances that create a kind of scar tissue. into a blood channel—and may not searchers are exploring the potential im-Smooth muscle cells migrate to the ves- cause angina or appear on images of the pact of gum disease. Infection from peri- ORAL AND WHOLE BODY HEALTH 15
  18. 18. EVALUATING THE DATA:Could Periodontal Disease Increase the Risk forCardiovascular Disease? BY K AUMUDI JOSHIPURAHEART DISEASE AND PERIODONTAL DISEASE have several loss-induced dietarythings in common. One of them is inflammation, which both narrows changes(e.g.,shunningcoronary arteries and breaks down the tissues that hold teeth in fruits, vegetables andplace. Could periodontal disease increase your risk for developing dietary fiber) thatheart disease, perhaps due to bacterial pathogens or inflammatory increase heart risks.chemicals carried by the blood from the mouth to the heart? If so, The link between thecould you reduce your heart disease risk by preventing or treating two diseases mayperiodontal disease? derive from factors that Research suggests that there may be links between the two influence both. Forconditions. Animal studies in particular offer provocative evidence example, cigarettethat certain biologic pathways might allow one disease to influence smoking is a major riskthe other. Periodontal bacteria are found in the plaque deposits that factor for heart diseasenarrow coronary arteries; inducing periodontal disease in rabbits and for periodontalcauses plaque accumulations in their coronary arteries. disease, and a genetic Other evidence comes from observational human studies. The sus c ep tibili ty tolargest such study, the National Health and Nutrition Examination inflammation mightSurvey (NHANES), involved 10,000 Americans between the ages of 18 cause someone to develop both diseases (see chart).and 74. It found that people with periodontal disease were much more Although periodontal disease seems to be associated with heartlikely to be diagnosed with heart disease than those without disease, more studies are needed before we can say with certaintyperiodontal disease. that one disease actually causes the other. Meanwhile, everyone Not all studies have yielded similar results. For example, my colleagues should be conscientious about treating gum disease, but it is not yetand I examined a group of health care professionals and failed to find an clear that doing so will protect you from heart disease. •overall association. Interestingly, our study and several others did detecta significant association between tooth loss (often a result of severe KAUMUDI JOSHIPURA is director of the Division of Dental Publicperiodontal disease) and heart disease. So the “connection” between Health at the University of Puerto Rico and also teaches at Har-periodontal disease and heart disease may be indirect, involving tooth- vard University.odontal disease pumps a continuous flow measuring the heat of blood vessels (be- tion’s ability to ward off infection out-of bacteria and cytokines into the blood- cause heat normally accompanies in- weighed its drawbacks. Today, as we livestream. Bacteria also produce toxins that flammation); and altering existing im- longer, exercise less, eat too much, andcan trigger inflammatory responses. Cy- aging technologies, such as MRI or CT smoke, many of us suffer from inflam-tokines and bacterial toxins can stimu- scans, to improve their ability to peer mation’s dark side—including its abilitylate the white cells in atherosclerotic inside vessel walls. Scientists are trying to contribute to atherosclerosis and otherplaques, prompting plaque growth or to develop molecular imaging tech- chronic disorders. Scientists continue torupture. Despite these links between in- niques to “visualize” biological process- pursue a deeper understanding of in-fection and atherosclerosis, current clin- es such as infl ammation, looking be- flammation’s role in atherosclerosis, andical evidence does not support the use of yond the anatomical features of blood to decipher the intricate interactions thatantibiotics to prevent recurrent compli- vessels. Geneticists are hunting for genes ignite and drive the inflammatory pro-cations following a heart attack. that predispose some people to chronic cesses in the arteries. These insights inflammation and atherosclerosis so should enable us to make further inroadsTOWARD EARLY DETECTION they can seek more aggressive monitor- against a disease with growing world-noninvasive methods for identifying ing and treatment. wide impact that causes extensive dis-vulnerable plaques might help pinpoint For most of human history, inflamma- ability and takes far too many lives. •at-risk individuals who lack warningsigns of potential heart attack or stroke. PETER LIBBY, who earned his M.D. from the University of California, San Diego, is chief ofIdeas include testing for elevated levels cardiovascular medicine at Brigham and Women’s Hospital, Mallinkrodt Professor ofof C-reactive protein, a substance in the Medicine at Harvard Medical School, and co-editor of Heart Disease, a classic cardiologyblood that signifies acute inflammation; textbook (W.B. Saunders, 2001).16 ORAL AND WHOLE BODY HEALTH
  19. 19. Smart Pair.Comprehensive Care. Oral-B® Triumph™ The world’s smartest toothbrush fights plaque and bad brushing habits. MOTIVATIONAL TIMER Tracks brushing time and gives positive feedback at 2 minutes. 4 BRUSHING MODES Deliver a customized experience—clean, soft, massage, and polish. BRUSHING GUIDANCE Encourages regular brushhead replacement. MULTILANGUAGE DISPLAY Can be programmed in 13 different languages. Crest® PRO-HEALTH™ A comprehensive toothpaste for all of these areas: CAVITIES TARTAR BUILDUP GINGIVITIS WHITENING PLAQUE FRESHENS BREATH SENSITIVITY Dedicated to healthy lifesmiles“The ADA Council on Scientific Affairs’ Acceptance of Crest PRO-HEALTH Toothpaste is based on its finding that the product is effective in helping to prevent and reduce tooth decay, gingivitis and plaque above the gumline, to relieve sensitivity in otherwise normal teeth, and to whiten teeth by removing surface stains, when used as directed.”© 2006 PG PGC-1713B OPAD06508
  20. 20. the three-way street Two decades of biomedical and dental detective work have linked obesity, diabetes and periodontal disease BY ROBERT J. GENCO I N T H E E A R LY 19 6 0 S , researchers from the National Institutes of Health (NIH) journeyed to the parched desert lands of the Gila River Indian Community in central Arizona to study the health of the Pima Indians. In the course of routine medical exams, they made a startling discovery: the Pima people proved to be fatter than any other group of people on Earth except for the Pacific Nauru islanders. Nearly half of those over the age of 35 had type 2, or adult-onset diabetes, eight times the national average. In order to survive in the desert, it seems that their thrifty genes may have evolved to carefully conserve fat through times of drought and famine. After World War II, when the tribe changed their traditional diet to an American one, their fat intake rose from about 15 percent to a whopping 40 percent of calories—and their genetic evolution backfi red. 18 ORAL AND WHOLE BODY HEALTH
  21. 21. N O R T H W E S T E R N U N I V E R S I T Y L I B R A R Y, E D W A R D S . C U R T I S ’ S “ T H E N O R T H A M E R I C A N I N D I A N ,” 2 0 0 3 HISTORY INTERRUPTED: When Arizona’s Pima Indians adopted a fatty American diet, their thrifty desert genes backfired. Almost half of adults over 35 developed type 2 diabetes—and also contracted severe gum disease at twice the normal incidence. ORAL AND WHOLE BODY HEALTH 19
  22. 22. 2 diabetes research from our studies both on the Pimas and on the popula- tion of Erie County in New York State, along with research from around the globe—Japan, Brazil, Chile, Finland, Slovenia and other nations. In nearly all of the studies, it was found that diabet- ics suffered from more severe periodon- tal disease that often appeared years or even decades before it did in the general population—and once a diabetic patient had periodontal disease, their sugar control worsened and they suffered fur- ther complications, including nerve damage and kidney disease. We combined the results of these studies and formulated a hypothesis that we and others could begin testing. This informational mosaic has given us a reasonable understanding of how obe- sity and diabetes are linked to infections such as periodontal disease. It also re- vealed a potential explanation of whyIN 1983, H. was healthy. Three years later, she suffered from out-of-control type 2 diabetes and diabetes is a significant risk factor forsevere gum disease, with abscesses ulcerating her gums and loose, shifted teeth. oral infection and inflammation—and why it often leads to periodontal disease As the NIH studies continued over clinics.) Diabetics fared the worst, with at a much earlier age than normal. Pa-the following decades, the researchers twice the normal incidence of gum dis- tients with type 2 diabetes are twice asdelved into other health issues including ease—and much more severe oral infec- prone to periodontal disease as nondia-kidney problems and heart disease. They tion than nondiabetic patients. betics, all other factors being equal.also suspected that there might be a In 1983 we examined H, a 32 year- An important piece of this puzzlehigher than normal incidence of gum old woman who was extremely over- emerged 10 years ago during the Eriedisease. In 1981 the Dental Institute weight, but otherwise quite healthy. In County study, conducted in metropoli-asked me to assess the periodontal health her follow-up exam two years later we tan Buffalo, N.Y. We discovered thatof the Pimas. At that time, I was in the were shocked to discover that her health obesity and periodontal disease were re-midst of clinical studies at the University had deteriorated precipitously: she suf- lated. We collected information on bothat Buffalo Periodontal Disease Research fered from uncontrolled type 2 diabetes the general and oral health of 1,250Center examining the body’s response to and had developed advanced gum dis- adults. After statistical adjustment forbacterial infection in the mouth—so I ease. Abscesses ulcerated her gums, and other periodontal risk factors includingwelcomed the opportunity to examine a her teeth were loose and had shifted out age, gender, socioeconomic status, smok-very different population. I spent three of position, leaving large gaps between ing, diabetes and dental plaque, the rela-days at the Gila River reservation con- her front teeth. Under normal circum- tionship remained strong: obesity ap-ducting several dozen clinical exams. stances, the progression of this condi- pears to be an independent risk for peri-Never before had I seen such severe, un- tion would have taken 15 to 20 years to odontal disease. Investigations by Nabiltreated periodontal disease. reach that level of infection. Bissada and his colleagues at Case West- In 1982 we established our first den- Her case sparked a question that we ern University in Cleveland and by Toshi-tal clinic in a trailer on the reservation, couldn’t answer. Could there possibly yuki Saito of Kyushu University in Fu-run by Dr. Marc Shlossman, and initi- be a connection between obesity, diabe- kuoka, Japan, mirrored our findings.ated a study to track the Pimas’ oral tes and oral infection? It took 21 years Another important clue surfaced inhealth. Since then, we have examined of medical and dental detective work, the mid-1990s that helped to explain the3,600 people, giving checkups every piecing together data from many sourc- role obesity plays in infection. We learnedtwo years. (Regular dental care was es, to understand this triangular rela- that fat tissue is not only a repository forprovided by the reservation’s dental tionship. We gathered the results of type fat cells but is increasingly viewed as a20 ORAL AND WHOLE BODY HEALTH

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