Learning from Science: How Oral-Systemic Collaborations Can Advance Research, Policy, and Health Outcomes

Laurie K. H. McCauley, DDS, MS, PhD, Professor and Dean, School of Dentistry, Professor, Dept of Pathology, Medical School, University of Michigan

Preeti N. Malani, MD, Chief Health Officer, Division of Infectious Diseases, University of Michigan, Director, national Poll on Healthy Aging. Institute on Health Policy and Innovation

Christopher Fox, DMD, DMSc, CEO, International Association for Dental Research and the American Association for Dental Research

Martha J. Somerman, DDS, PhD, Chief, Laboratory for Oral Connective Tissue Biology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, Senior Advisor, National Institutes of Health

Abstract. Science is the driving force for integrating dentistry and medicine in research, education and practice. Accordingly, the Santa Fe Group’s ‘first webinar in the Continuum series highlighted the science base for integration. Dr. McCauley noted a dramatic increase over the decade in research associating chronic oral infectious disease with a wide array of systemic diseases and disorders. Moreover, employing conservative interventions to control the oral infection has had positive effects in mitigating the symptoms or progression of the systemic disorder. Most notably this has been documented in cases of periodontal disease in relation to type 2 diabetes. She went on to describe the deleterious effects of chronic oral disease more broadly in terms of increasing all -cause mortality risk, possibly due to an acceleration of cellular aging. She urged adoption of implementation science and “learning health systems” to accelerate the transfer of research into practice, decrying the gaps that leave too many providers, both physicians and dentists, unaware of the oral-systemic tissue connections.

Successful integration, on the other hand holds promise of improved health outcomes, reduced health disparities and greater health equity, but depends on informed consumers so an understanding of how Americans regard oral health is important, and was the theme of Dr. Malani’s talk. As Director of a new National Poll on Healthy Aging, conducted out of the University of Michigan, which surveys a sample of Americans ages 50 through 80, she summarized findings revealing that not only do older Americans value oral health, but many are often unable to afford dental insurance or lose coverage in retirement. She found that many of those most in need were poor and minority groups who said they were embarrassed by their appearance. Along these lines, Dr. Malani also reported that patients who received dental care in an expanded Medicaid program in Michigan said that having good oral health would improve their job prospects. Ninety-eight percent of seniors queried in the national Poll said they would like to see a dental benefit added to Medicare and 57 percent said they would be willing to pay extra to obtain it.

As a reactor to the talks. Dr. Fox confirmed support of integration and collaborative team efforts by the major dental research associations, both nationally and internationally. Oral disease remains of the conditions constituting the global burden of disease he noted, and reported that other global health organizations, particularly the World health Organization, are amplifying the message, through recent proclamations and resolutions, that good oral health is essential and must be included in research, workforce models and health services delivery in order to achieve optimal overall health and quality of life.


The oral microbiome numbers over 1,400 species, making it the second most diverse colonization site in the human body, Dr. McCauley noted. Since the most common dental diseases are caused by bacteria, and their destruction of oral tissues can open a pathway to the general circulation, it is not surprising that oral bacteria can find their way to other parts of the body. To date, species of periodontal disease bacteria have been linked to 57 different systemic conditions she said. Most prominent are associations with type 2 diabetes, cardiovascular and cerebrovascular diseases, osteoporosis, Alzheimer’s disease, some cancers, liver and lung diseases, rheumatoid arthritis, and complications of pregnancy. Beyond initiating an inflammatory response, exactly what the oral invaders are doing remains to be known but is undoubtedly complex. For example, in osteoporosis the periodontal bacteria found in the bone marrow apparently promote an increase in cells that cause bone loss. Oral-systemic connections have also been found to be bidirectional in some cases. Thus, diabetic patients with poor glycemic control are at increased risk of developing periodontal disease, or if already infected, see their periodontal symptoms worsen. The good news is that interventions to control or prevent periodontal disease have resulted in forestalling or ameliorating the associated systemic problems. This has been demonstrated in many studies of diabetes but also in cases of cardiovascular disease, rheumatoid arthritis, and more recently, in studies of pneumonia in nursing home and hospital patients. Basic improvements in oral hygiene for these patients have significantly lowered the risk of their developing and/or dying of pneumonia, which, not incidentally, has also resulted in major health care cost savings.

Given the consequences of chronic periodontitis on life-threatening systemic diseases, are there implications relating to an overall mortality risk from periodontitis? The answer is yes, said Dr. McCauley, who reported on a meta-analysis of studies involving 5.7 million participants that found that periodontitis was associated with an increased risk of all-cause mortality. A possible cause maybe an accelerated biological aging process characterized by decreased telomere length. Telomeres are chains of DNA pairs found at the ends of chromosomes. Each time a cell divides it loses some telomere pairs but in a large national sample researchers found that cells of individuals with moderate to severe periodontitis exhibited significantly greater telomere shrinkage compared to healthy individuals, presumably related to chronic infection and persistent local and systemic inflammation. Dr McCauley went to point out the relevance of the oral cavity in the current coronavirus pandemic, both as the portal of entry for infection but also that in the presence of periodontitis, Covid-19 patients experienced more serious complications and higher markers if inflammation.

Dr. McCauley’s concluding remarks were a sobering reflection on the failure to translate all the well-documented evidence of oral-systemic tissue interactions into the education and practices of both the medical and dental communities. One review of the literature, reflecting over 4,000 physicians, indicated that 35 percent were not aware of the periodontitis-diabetes association and 30 percent had never referred a patient for an oral health assessment. On their part even among dentists who are part of the National Dental Practice-Based Research Network (NDPBRN) only 72 percent said they occasionally conduct a general health risk assessment of patients, such as measuring blood pressure or asking about diabetes. Those who never do cited the lack of time or reimbursement. To remedy the situation, Dr. M McCauley strongly urged adopting the tools and techniques of implementation science and “learning health systems” to accelerate knowledge transfer. She further encouraged increasing collaborative dental-medical teams in research and practice, and proposed that the NDPBRN expand the scope of its network to include physicians and other non-dental providers. The lack of interoperable dental and medical electronic health records is also a serous barrier to integration she said, and needs to be addressed.

In contrast to the inertia that keeps medical and dental practices separate and not connecting Dr. Malani’s presentation suggests that Americans, at least those middle-aged and older, care about oral health and not just for its own sake. The University of Michigan which conducts a National Poll on Healthy Aging, found that 98 percent of Americans aged 65 to 80 said that their oral health was important to them and that oral health problems can lead to other health problems. But in slide after slide it was clear that access and affordability were serious issues in obtaining dental are, with more affluent consumers seeking annual dental visits for routine exams and preventive cleanings while poor and minority groups, if they sought care at all, cited a serious dental problem, with many saying they were embarrassed about their appearance. Dental insurance coverage also was skewed in favor of those with higher incomes compared with poor and minority individuals.

Issues of dental care mount for those 65 and older since Medicare dental coverage is extremely limited. Some seniors lose employer-based dental insurance when they retire. Others—47 percent in the National Poll—go without any dental insurance. Some indicated that their choice of a Medical Advantage Plan over traditional Medicare was because the plan included dental coverage. An overwhelming 93 percent of those polled favored adding a dental benefit to traditional Medicare—and 59 Percent said they would be willing to pay extra for it.

Dr. Malani concluded her talk with findings from a recent expansion of Medicaid in Michigan to include oral health benefits. A majority of enrollees reported that they had seen a dentist at least once since participating and said their oral health had improved. The percentage was even higher among Black respondents and those who said they had been uninsured for a year or more. Interestingly, many said that improved oral health improved their job prospects.

As the final presenter in the webinar Dr. Fox was an enthusiastic reactor to the previous presentations, confirming that the International and American Associations for Dental Research are fully on board supporting integration and pointing out that oral diseases remain the most prevalent of diseases in the global burden of disease studies. Further, the current Covid-19 pandemic only underscores the value and importance of the dental contribution in understanding and controlling the virus. He discussed the role of the oral tissues as the route of infection and transmission of Covid-19 and the site manifesting a wide array of symptoms. As well, dentistry’s long tradition of infection control is being applied to mitigate aerosol spread of the virus in dental offices and other health facilities. Dentists have also qualified as Covid-19 vaccinators, which could readily be extended to allow vaccinations against other pathogens.

Dr. Fox then turned to a series of newly emerging national and international documents which testify that oral health is essential to achieving optimal overall health and wellbeing and the necessity of including oral health in research, workforce models, and the delivery of health services. Principal among them is a resolution by the World Health Organization, adopted by the Executive Board in January 2021, and expected to be adopted by the World Health Assembly in 2021. The resolution calls on member states “to integrate oral health within their national policies, and, as part of general health, to reorient the traditional curative approach and move toward a preventive and health promotion approach to oral health…” Other advocacy groups he mentioned included the Friends of National Institute of Dental and Craniofacial Research and the Center on Budget and Policy Priorities.

The Webinar concluded with a brief Q and A session which focused primarily on ways to close the gap separating medicine and dentistry. Implementation science came up again as an important tool as well as the need to foster collaborations in research and practice. Expansion of the National Dental Practice-Based Research Network to include physicians was also mentioned. The speakers also saw the need to start the integration process early during education and training. This would mean having dental and medical students work together on research projects and providing care to patients in clinics.

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