After rather devastating negative conclusions made in a systematic review (SR) of the literature regarding the long claimed, possibly causal, relationship between periodontitis and atherosclerotic vascular disease by Lockhart et al. (2012), a highly alerted group of members of our specialty organizations, the Amercian Academy of Periodontology and the European Federation of Periodontology, had hastily organized a joint workshop, in the end of 2012, to fix unwelcome results of a number of large intervention studies by creating new systematic reviews on the Perio-Systemic link. The clear aim was to cement, once and forever, the claim of the number one clinical problem: periodontal disease and general health are closely related.
While the proceedings had been published, open access, in special issues of our main professional journals, the Journal of Clinical Periodontology and the Journal of Periodontology, workshop participants of the EFP presumptuously condensed the 209 pages of the 16, mostly valuable, papers in a nutshell, strangely called Manifesto.
No wonder when our professional societies and academies want to promote it with the above images. The Facebook page of the German Society of Periodontology features the left image while the right supports a recent statement by the American Academy of Periodontology’s President, Dr. Wayne Aldredge, regarding the U.S. Departments of Agriculture and Health and Human Services recent decision to remove flossing from the federal 2015-2020 Dietary Guidelines, citing the gap in quality research.
Readers may have noticed my dismay about our “thought leaders'” recent attempts to revive the perio/systemic issue despite emerging evidence of no or very small, irrelevant, effects of periodontal treatment in large-scale intervention studies on HbA1c in type 2 diabetes, or pregnancy outcomes.
I had yesterday discussed via email with a critical mind in the U.S. the results of another intervention study on cardiovascular events which never made it beyond a pilot study, the Periodontitis and Vascular Events, or PAVE, study. Since periodontitis patients were not randomized according to whether they received periodontal treatment but according to a community comparator (referral to community dentist with copy of x-rays and letter with diagnosis and recomendations for treatment), I had argued that such a design would not fulfil criteria of an RCT since patients who get proper periodontal treatment in the comparison group may fundamentally differ from those who won’t care. However, patients who won’t care in the test group would get the treatment anyway. So, interpretation of biased results would be difficult if impossible. Not surprising, the PAVE study did not get funding after the pilot phase (Beck et al. 2009) [pdf], which resulted in non-significant differences anyway, possibly (but not inevitably) due to lack of statistical power.
New Orleans was still the Big Easy. Hurricane Katrina would devastate the southern metropolis about a decade later, and my attendance of the annual meeting of my main professional society was a nice relief of the daily monotony at my dental school at home. I met many of my colleagues and I had a fantastic dinner on a Mississippi paddle steamer which was sponsored by a company with which I was working at that time.
It was one of the very first occasions that scientists in my discipline talked about a possible relationship between poor oral health and dangerous chronic conditions such as cardiovascular and cerebrovascular diseases. One of our most distinguished Professors in the field commenced his presentation with the message “Floss or Die”, a really frivolous statement. He later put the alleged relative risk for getting an infarction or stroke to 1.3 or so in case of more severe oral disease. It was the beginning of an endless discussion which mostly interested the numerous practitioners who, whithout any knowledge about odds or risk ratios, bothered their patients during the next decade with the menace of myocardial infarction, ischemic stroke, low birth weight, etc., if their oral diseases had not properly been treated. Most of this has vanished in the meantime and more realistic views have emerged.
What I didn’t know at that time was that the distinguished Professor in Oral Biology had just received an award in Economics. Not the real Nobel Prize but the “IgNobel Prize”. It stands for ignoble, and it is in fact a parody for achievements that “first make people laugh, and then make them think.” The chief sponsor of the prize is the Annals of Improbable Research which is a successor to a periodical that satirized scientific publications. That particular year, Jacques Chirac was among the laureates who, as the French President, had just launched a series of atomic bomb tests in the Pacific Ocean while the world was observing the 50th anniversary of the Hiroshima massacre. It was the Peace prize, of course. Understandably, he didn’t show at the ceremony in Harvard University’s Memorial Hall where the prizes were conferred about 2 months before the real ones each year since 1991.
Our distinguished Professor got the prize in Economics for his remarkable discovery that “financial strain is a risk indicator for destructive periodontal disease.” Of course, he didn’t accept the prize either but rather ignored the event. It was long before the financial markets went out of control, somewhat before the dot-com bubble emerged and finally burst in 2000. People at risk for gum disease (according to our Professor those in financial trouble) have not participated in either bubble, I suppose.
All of this is certainly not related to the decline of periodontal disease which has been observed over the last decade or so. A slide with “Floss or Die” is still in use to attract the interest of my undergraduate and graduate students. But as ever, more as a joke than a serious suggestion.
First published at Freelance.
The recent joint workshop of the European Federation of Periodontology and the American Academy of Periodontology, apparently meant to revive again (and once and forever establish) the periodontitis/systemic disease issue, has resulted in remarkably weak conclusions in some of the seminal papers, for instance,
- As regards pregnancy outcome: “Current evidence from RCTs does not support the provision of periodontal therapy to improve pregnancy outcomes” (Michalowicz et al. 2013).
- As regards diabetes mellitus: “The modest [a meta-analysis indicated a mean treatment effect of -0.36% HbA1c (CI -0.54, -0.19)] reduction in HbA1c observed as a result of periodontal therapy in subjects with type 2 diabetes is consistent with previous systematic reviews. Despite this finding, there is limited confidence in the conclusion due to a lack of multi-centre trials of sufficient sample size are lacking” (Engebretson and Kocher 2013).
- As regards biomarkers and cardiovascular disease outcomes: “There is […] limited evidence that these acute [short-term inflammatory response] and chronic changes [progressive and consistent reduction of systemic inflammation and improvement in endothelial function] will either increase or reduce CVD burden of individuals suffering from periodontitis in the long term” (D’Aiutu et al. 2013).
Very large intervention studies which could challenge existing evidence, as demanded during the workshop (“Well-designed intervention trials on the impact of periodontal treatment on prevention of ACVD [atherosclerotic cardiovascular disease] hard clinical outcomes are needed,” Tonetti and van Dyke (2013)), may be very difficult to conduct. Mainly beneficial effects of periodontal treatment (essentially unrelated to systemic diseases and conditions under scrutiny) have already been shown, so denial of treatment for control patients must be regarded unethical.
8 May 2013 @ 6:20 pm.
Last modified May 8, 2013.