Periodontal Myths and Mysteries Series (VIII) – Disabling Periodontitis

Shortly before recent updates of the Global Burden of Disease (GBD) studies (supported by the Bill & Melinda Gates Foundation) sparked considerable attention in the news, dubious metrics like disability-adjusted life years (DALY) and years lived with disability (YLD) had been calculated for a number of oral diseases and conditions such as (severe) periodontitis. These metrics are basically derived from estimates of incidence (and, recently also, prevalence) of the disease, and a disability weighing factor; but interpretation must be regarded spurious. One may intuitively ask the important question, cui bono?

In its recent update on the global burden of oral diseases, Kassebaum et al. (2017) claimed 538 million cases of severe periodontitis worldwide in 2015, 231 million more than estimated for 1990. Disability-adjusted life years (DALY) for severe periodontitis were calculated at 3.518 million. In a recent white paper by Tonetti et al. (2017), this latter figure was emphasized, “3.5 million years lived with disability.” These authors further their arguments about the “Impact of global burden of periodontal diseases on health, nutrition and wellbeing of mankind” by adding estimates provided by Listl et al. (2015) on the global cost of lost productivity from severe periodontitis alone (54 billion USD/yr). Productivity loss values 1 DALY as 1 yr of per capita gross domestic product.

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Professor Dieter E. Lange †


Photo: FZ, under fair use

Shortly after his 84th birthday, Professor Dr. med. dent. Dr. h.c. Dieter E. Lange,  former director of Germany’s once largest, independent department of Periodontology at Westfälische-Wilhelms-Universität Münster, passed on 12 September.

At a time when Periodontology in Germany was largely non-existent in the dental curriculum and consequently in dental practice, Professor Lange started, in 1978 after having been appointed in Münster, his crusade for prevention and treatment of periodontal diseases. He was the one who managed to get soon afterwards approval, by the Westphalian-Lippe dental association, of Germany’s first and still only postgraduate education program in Periodontology. I had had my education in Perio in Marburg, Hesse, but if I wanted to get a respective official certificate I had eventually to move to Münster, what I actually did in 1987.

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The Crux of Google Scholar Accounts

What’s wrong with a Google Scholar account? Everybody loves it, right? Years ago, I had created one (it needs just a Google account) and cleaned it from unrelated (as scientists with my last name and initials are plenty) articles. It neatly lists all my publications (in the order of highest to lowest quotations).  It tells me (and others who might be interested in my work) the number of quotations and the number of recent quotations. It calculates my h-index and several other more or less informative metrics. And it alerts me of recent quotations, so I can easily check who quoted me and in which context.

Google Scholar’s algorithm doesn’t consider a “core collection” as Web of Science of Clarivate Analytics does. That means that Google Scholar also regards quotations in articles published in questionable open access journals, cites in doctoral or master theses (but, as far as I know, not books). And also quotes of books. In my opinion, a quotation is a quotation and if correct, it’s okay.

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Scrutinizing the Perio-Systemic Link?

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.

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No Dentistry Nobel Laureate

UPDATE below.

When I was approached by the Nobel Committee at Sweden’s Karolinska Institute in October last year, probably as having been recognized as “[h]older of [an] established post as full Professor[s] at the faculties of medicine in Sweden [or] holder[s] of similar post[s] at the faculties of medicine or similar institutions in Denmark, Finland, Iceland and Norway”; and invited to nominate a possible candidate for the Physiology and Medicine award 2017, I was wondering whether there would be a dentist who might deserve the honor.

According to Alfred Nobel’s (1833-1896) will,

[t]he said interest shall be divided into five equal parts, which shall be apportioned as follows: /- – -/ one part to the person who shall have made the most important discovery within the domain of physiology or medicine …

Well, I checked out most prolific and highly cited dentistry professionals (of course with a focus on Perio), made myself aware of previous years’ laureates, and immediately noticed there was none. Dentistry has made advances in the past hundred years or so, no doubt. But, when considering Perio (my field of interest), it might in fact be questioned whether our understanding of the pathogenesis of periodontal diseases has witnessed fundamental breakthroughs after, say, the late 1970s. Whether basic principles of treatment have changed. As a matter of fact, innovations, such as regenerative treatment, had no lasting effect as respective methods may be applied in a minority of lesions, i.e. deep infrabony lesions and a few furcation involvements only. And the main issues, prevention and treatment of more aggressive forms, seem to be yet unresolved. What appears to thrill both young and old dentists right now is a one-hundred-year-old claim of focal infection, the so-called Perio-Systemic link.

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