In the current issue of JOP two renowned American clinicians reflect on what they believe shaped modern periodontology, Michael K. McGuire and Thomas G. Wilson. I was a bit hesitant when considering commenting on their musing. When browsing through the AAP’s Open Forum every other day (basically a community made of American periodontist practitioners which is rarely joined by AAP officers or scientists for helpful clarification about what is evidence and what not) I met quite a lot professional frustration and, well, cluelessness.
Evidence based dentistry may have emerged not earlier than 15 years ago; with very revealing results. Only now, we may be able to grade the evidence and make reasonable recommendations: strong or weak, for or against. For instance, based on still moderate quality of evidence, GTR may only weakly be recommended for the treatment of a very limited number of certain periodontal lesions. Hasn’t that been a “megatrend” of the 1980s and 1990s which is over in 2014?
And then, practitioners may actually perceive “trends” when scientists may talk about “hot” issues. Periodontology has suffered for a long time from a terrible misconception: practitioners applied “hot” issues which they perceived as trends.
No, the perio-systemic link is not a game changer. I am not aware that the life of any perio-patient had been saved by properly treating his/her periodontal disease. And no, EBM is not a megatrend. It is the basis for every-day decision making in a field where expert practitioners are in the comfortable situation that they can rely on systematic reviews and many meta-analyses which cover most of our clinical questions. And again no, laser therapy, local delivery and host modulations are no wild cards anymore. McGuire and Wilson compare the situation reagrding these approaches with implant dentistry which has apparently transitioned from a dubious approach to standard of care. Well, that’s true, but it was EBM which made it possible. And it’s EBM which has not provided high quality evidence for the latter.
McGuire and Wilson conclude with, “Clearly these are exciting times!” when thinking of “3-D printing, salivary diagnostics, live cell therapies, minimally invasive techniques, and many more.” I am afraid that their patients will instantly share their opinion. Unjustified enthusiasm is one of the main prerequisites for a successful practitioner.
2 August 2014 @ 11:57 am.
Last modified May 11, 2016.
I have written about AAP’s centennial and the series of papers celebrating the “literature that shaped modern Periodontology” in several posts, see here and here. In this month’s contribution (in the Academy’s Journal of Periodontology), Steven Offenbacher and James Beck attracted my attention when writing about “Changing Paradigms in the Oral Disease–Systemic Disease Relationship.” Twenty-five years after the first report by Finnish researchers on a certain risk of poor oral health for cardiovascular disease, the incredibe surge of studies all over the world (“Floss or Die!”) may have ceased, paving the way for another overdue paradigm shift.
The paper disappoints. Instead of putting the initial and long-lasting exciting in at least some relation in view of results of recent very large intervention studies which were by and large not able to confirm a postulated beneficial effect of treatment of periodontal disease on cardiovascular disease, low birth weight or diabetes, Offenbacher and Beck opened the bottom drawer and pulled a couple of now questionable studies which, well, misled the public and thousands of researcher worldwide alike. For instance, Frank De Stefano’s paper of 1993 who, based on NHANES I follow-up data, reported a 25% increase of risk in patients with periodontitis. The data had been re-analyzed by Phillipe Hujoel in 2000 including much more careful adjustment of cofounders. They could not find an association. I have reported about the apalling letter to the editors of JAMA by Robert Genco and colleagues here.
And then, of course, the paper by Beck et al. (1996) from the VA Longitudinal Study.
“Our paper showed that periodontal disease was a significant independent risk factor for CVD events after adjusting for traditional risk factors and displayed a dose-dependent increase in risk with increasing periodontal disease severity. Importantly, this paper described a two-component mechanistic working model that linked periodontal disease to cardiovascular disease via systemic bacterial dissemination interacting with the vasculature and activation of the hepatic acute phase response as an inflammatory trigger for CVD. We also hypothesized that there may be an underlying hyperinflammatory trait that served to increase risk for both conditions, suggesting that bacterial exposure in those susceptible individuals would result in even more risk for CVD. In addition, by placing importance on inflammation, it explained how oral infection could influence multiple conditions such as diabetes. Over the next 10 years, many studies supported this basic model. The model is now more than 15 years old, and we would modify it only by adding specific details, such as the hyperinflammatory trait likely being attributable to genetic differences in the innate immune response.” (Emphasis added.)
Bruce Pihlstrom’s account on the occasion of AAP’s centennial, which is published in the recent issue of Journal of Periodontology, is sober and very honest. He had been asked to write about the literature on treatment of periodontitis with a focus on bacterial removal and proper home and professional care. Of course, that is what matters. Within Dentistry, and beginning with Sigurd Ramfjord in Ann Arbor and Jan Lindhe in Gothenburg, periodontists have always been frontrunners in the conduction of randomized clinical trials, and what can be achieved by removal of bacteria and making sure that recolonization is under control has a firm basis.
“When the results of trials that showed the efficacy of ‘non-surgical’ periodontal therapy were first published or presented at periodontology meetings, many suggested that the trials were flawed or that the investigators did not know how to properly trate periodontal disease with whatever treatment happened to be favored by critics of the studies. As various groups of academic and private practice periodontists published similar findings from around the world, it was confirmed that both ‘surgical’ and ‘non-surgical’ therapy were efficacious. Use of surgical flap procedures may provide better visual and mechanical access to the root surface and allow approaches to regenerate the attachment apparatus. However, accumulated scientific evidence clearly showed that removal of deposits from the root surface, effective personal oral hygiene, and regular professional periodontal maintenance were the critical foundation of periodontal therapy.”
As has been mentioned, the American Academy of Periodontology celebrates in 2014 her centennial. On that auspicious occasion, several themes which have shaped modern Periodontology have been identified by the Editor-in-Chief, and prominent opinion leaders asked to give brief summaries on each. The first commentary on “Bacteria [that] Play a Critical Role in the Etiology of Periodontal Disease” by Professor Niklaus P. Lang 2014 has just appeared in the February issue of the Journal of Periodontology. The title is remarkably conservative, avoiding any claims as regards periodontal diseases’ “causes”.
The brief digest summarized fifty years of oral microbiology as regards periodontal research, mentioning ground-breaking work by the Socransky group in Boston, MA; Slots in Copenhagen and later Buffalo, NY, together with Genco; as well as Loesche in Ann Arbor, MI; and Moore and Holdeman-Moore in Richmond, VA. But it also quickly focuses, in a couple of paragraphs, on the famous study on Experimental Gingivitis in Man of 1965 by one of the most eminent Norwegian periodontists, Harald Löe. Right now, the paper has been cited 2533 times, while its set-up has been repeated several hundred times for different research questions. Lang explains,
“It [the Experimental Gingivitis in Man paper] reported a straightforward, hypothesis-driven clinical experiment with only 12 volunteers, and it asked the question: Would the amount of plaque mass buildup on the teeth result in gingivitis?
During a 3-week period of no oral hygiene, all volunteers predictably developed generalized gingivitis, and upon reinstitution of oral hygiene practices, they returned to pre-experimental low levels of plaque and gingivitis. Some of the power of this study came from unique and innovative design features, including the use of healthy young human volunteers with no systemic diseases, no malnutrition, and no occlusal trauma. In addition, the participants were their own controls, so they were all taken to a healthy gingival status at baseline, induced to gingivitis solely by the absence of oral hygiene, and then returned to health solely by reinstitution of oral hygiene.”
It is worth to revisit the paper by Löe et al. (1965) after almost 40 years. Nine first-year clinical students, one teacher in Periodontology and two laboratory technicians participated in a clinical and microbiological experiment. There was no mention as regards health or occlusion. At first exam they had low, but not zero, Plaque Index (PI) scores (means between 0.00 and 0.95), which had been described the year before by Silness and Löe (1964) and low, but not zero (0.02-0.69), Gingival Index (GI) scores (Löe and Silness 1963). Although throughout scores on altogether one thousand gingival units, as the authors mention, were considered which were, according to Lang (2014) “well-defined”, Löe et al. (1965) generally averaged scores at the tooth level, groups of teeth, the area level, the subject level and the cohort level. Thus, fractions of an integer (for instance 0.60) have to be interpreted as frequencies of scores (e.g., 40% score 0, 60% score 1), since only scores were “well defined”. There was actually no preparatory phase when plaque and gingival inflammations was brought to zero. Participants, who were consistently called “patients” in the paper, withdrew from all oral hygiene and were “rechecked at varying time intervals, and a full assessment of their plaque and gingival status was carried out each time using the same criteria at the introductory eaxmination. As soon as inflammatory changes were observed and a complete index and bacteriological assessment had been made, the patients were given detailed instructions in oral hygiene methods using brush and wood massage sticks.” “At a point where the GI and PI scores approached zero, the experiment was terminated.”
While all of us eagerly await the promised monthly comments on eleven themes which have been identified by J Perio’s Editor-in-Chief Dr. Kenneth S. Kornman and colleagues Drs. Paul B. Robertson and Ray C. Williams, your humble blogger will just go ahead sharing with my readers own thoughts which came to my mind when reading the extensive reading list on the Literature That Shaped Modern Periodontology. As the responsible teacher of Perio at The Arctic University of Norway, I feel obliged to put the list somewhat into perspective, in particular since Kornman et al. focus on just highly cited papers (which may frequently represent mainstream) and further consensus papers of importance as suggested by various U.S. postgraduate program directors. And especially as a highly esteemed colleague representing another subject here has put the list on fronter as if it was the best since the invention of chocolate ice cream. Since, for undergraduates, the list inevitably will cause if anything but shock and awe, there is apparent need for some moderation.
4. Periodontitis and Other Systemic Diseases Interact – in Both Directions
First, I want to make sure that I am no heretic. Interaction between periodontal disease and systemic health is, of course, an old story which has only been revived about 25 years ago, undoubtedly to some success for larger parts of our profession. For instance, even before 1990 or so it was well known that diabetes mellitus is associated with considerable periodontal morbidity. On the other hand, when having a look at clinical studies back in the 1970s and 1980s, one frequently reads that periodontitis patients “otherwise healthy” had been enrolled in the trials. After having realized in the meantime that periodontitis is associated with whatever chronic disease or condition is considered, be it lung cancer at one extreme or erectile dysfunction at the other, one can only come to the conclusion that the topic, which gets so much attention nowadays, had in the old days completely been ignored (as had been the effect of smoking on periodontal health). That “bad dentistry” may have, in certain cases, even fatal consequences is, on the other hand, not a new idea but had led, in particular in the United States and later, for instance, in Germany to what was sometimes vilified “Gnathology”, which should not be mistaken just as “occlusal ideology” but rather striving for proper biological function of fixed and removable restorations.