Tagged: case definition

Looking Forward to a New Classification System? Or Rather Not

It was tempting to write another post in the Periodontal Myths and Mystery Series – Clinical Measurements in Periodontal Disease. Guesswork whenever it comes to submarginal landmarks such as the cemento-enamel junction and bottom of the pocket; or, even worse, an assumed “tangent to the prominences of two roots” to “measure” furcation involvement. After having introduced and refined case definitions of mild, moderate and severe periodontitis for epidemiological surveys in the past decade, the same authors representing the American Academy of Periodontology and the U.S. Centers for Disease Control and Prevention had to concede, in a recent article in the Journal of Periodontology, that,

[t]hese subgroups [mild and moderate periodontitis] are not truly ordinal [sic] as the label suggests because many ‘moderate’ cases had insufficient pocket depth to qualify as ‘mild’ and we have therefore combined them and used the label ‘other‘ periodontitis,

adding even more confusion [1]. When the paper went online earlier this year, I had contacted one of the authors, Dr. Wenche Borgnakke, to explain that sentence. I had even suggested,

So, in some cases there was >= 4mm CAL but no deep pockets of >=5mm, only 4mm. So, if CAL would have been 3mm, one would have assigned it to ‘mild’, but since it was 4+mm, it had been ‘moderate,’

asking her whether I was possibly right. Unfortunately, she did not respond.

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Update and Clarification of Periodontitis in Adults in the United States

Yesterday, new NHANES 2009-2012 data on prevalence, extent and severity of periodontitis have gone online in the Journal of Periodontology. On first sight, authors confirm findings of the previous, 2009-2010, survey in that prevalence is much larger as previously reported. So, 46% of U.S. adults have periodontitis with almost 9% having severe disease (Eke et al. 2015). The previous report (Eke et al. 2012a) contained an unclear description of how attachment loss was measured concealing that a “signed” measure of recession was used to calculate clinical attachment loss as difference of probing pocket depth and recession (from Latin, recessus, retreat). In a letter to the Editor-in-Chief of the Journal of Dental Research, Professor Giannobile, I had raised more problems in the article when I wrote,

“Teaching in particular undergraduates about how probing parameters periodontal probing depth, attachment level, and recession are measured is quite an effort but usually straightforward. In order to avoid undue exaggeration of prevalence, extent and severity of periodontitis both in the population and in patients attending a common office and to be able to assess treatment outcomes, metric periodontal probing parameters have to be properly defined. I would therefore appreciate if authors could comment on the apparent redefinition of attachment loss in their paper. When analyzing the Figure in the paper by Eke et al. (2012a), what immediately hits the eye is that there seems to be higher prevalence of attachment loss at different thresholds (a) than of pocket depth at respective thresholds (b) in all age groups. Such a pattern may actually be a result of how attachment loss had erroneously been redefined, most probably due to convenience. Just as a trivial example, a 4 mm probing depth without recession may be associated with either 0, 1, 2, 3, or 4 mm attachment loss, but the NHANES oral health data management program would have “instantly calculated” 4 mm. Based on the new case definition using attachment loss in addition to probing depth, prevalence of all periodontitis in the adult population of 30 years and older in the U.S. has now been estimated to exceed 47%, after 35% found in NHANES III during 1988-1994. This much higher prevalence may be due to the redefinition of attachment loss, too. Moreover, as to Eke et al. (2012a), mild periodontitis has a rather low prevalence in all age groups while moderate periodontitis is widespread (Figure c). The picture was different in NHANES III when severe periodontitis occurred with lowest, moderate periodontitis with intermediate and mild periodontitis with highest prevalence, a pattern which, I suppose, applies to many other widespread chronic diseases. The strange new pattern might indeed be explained partly by the redefinition of attachment loss as well, ultimately leading to a different distribution of cases.” (Emphasis added.)

Subtracting recession from periodontal probing depth makes sense only when true recession (the free gingival margin is located apical to the cemento-enamel junction) gets a minus sign. This was circumstantially explained to me in an email by the authors forwarded to me by Professor Giannobile, who never published my original letter. Eke et al. (2012a) had actually concealed that a signed recession definition was used. In the new update of NHANES 2009-2012, calculation of clinical attachment is now correctly described, including the signed recession definition. Eke et al. (2015) may also have realized that there is no complex chronic disease where moderate severity is more prevalent than its mild form. It is rather perplexing to see that authors have now abandoned the differentiation between moderate and mild periodontitis which they call “other” periodontitis (other than severe). They give the following reason,

“These subgroups [mild and moderate periodontitis] are not truly ordinal [sic] as the label suggests because many ‘moderate’ cases had insufficient pocket depth to qualify as ‘mild’ and we have therefore combined them and used the label ‘other‘ periodontitis.”

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