An American Academy of Periodontology Task Force (AAP-TF) has recently reported about a planned update of the 1999 Classification of Periodontal Diseases and Conditions . I have written about it here. As the update is announced for 2017, I suppose that the AAP-TF report is meant to initiate some discussion as “[c]oncerns had been expressed by the education community, the American Board of Periodontology, and the practicing community that the current classification presents challenges for the education of dental students and implementation in clinical practice”. The AAP-TF report focuses in particular on attachment level, chronic versus aggressive, and localized versus generalized periodontitis. In my previous post, I had raised some concerns about the task force’s intention to keep the current differentiation between aggressive and chronic periodontitis and referred to an interesting essay by Baelum and Lopez (2003). As these authors have just published a harsh comment on the AAP-TF report, it’s interesting to see that we agree and utterly disagree in certain matters.
Attachment level measurements
The 1999 Classification indeed categorized severity of periodontitis only by amount of clinical attachment loss, slight, moderate, and severe (i.e. 1-2 mm, 3-4 mm, and 5 mm or more, respectively). Albeit attachment level measurements are important “for the scientific advancement of the knowledge of periodontitis”, the AAP-TF recognizes that attachment level measurements are challenging, time-consuming, difficult and “may involve some guesswork when the CEJ [cemento-enamel junction] is not readily evident via tactile sensation.” Consequently, they advocate new guidelines for determining severity, slight or mild, moderate, severe or advanced, of periodontitis which include, in addition to those based on clinical attachment level measurements, probing depths (>3 mm & ≤5 mm, >5 & <7 mm, and ≥7 mm, respectively), and radiographic bone loss (up to 15% of root length or 2-3 mm, 16-30% or 4-5 mm, and more than 30% or 6 mm or more). Bleeding on probing has always to be present if a diagnosis of periodontitis is to be made.
Concerns about increasing antibiotic resistance (e.g., methicillin-resistant Staphylococcus aureus, multidrug-resistant tuberculosis, antibiotic resistance of bacteria causing common infections of the urinary tract, pneumonia, or bloodstream infections), which jeopardizes effective prevention and treatment of life-threatening infections should be taken seriously when considering adjunct antibiotic therapy of periodontal diseases. After all, periodontal infections are not life-threatening diseases and can usually be controlled without adjunctive antibiotics. Apart from generalized severe cases, chronic periodontitis should not be treated in the first place with adjunct systemic antibiotics. In cases of aggressive or refractory periodontitis, microbiological diagnosis may allow targeting specific pathogens such as Aggregatibacter actinomycetemcomitans or Porphyromonas gingivalis. Responsible use of antibiotics takes into account the possible development of bacterial resistance, antibiotic toxicity and the risk of sensitizing.
Moreover, reducing the need for periodontal surgery by adjunct antibiotics may be short-sighted (note that I had written about this on several occasions here on this blog). Anatomical defects such as furcation involvement and infrabony lesions, which are the main indications for periodontal surgery, won’t resolve after subgingival scaling and adjunct antibiotic treatment. In light of the global problem of antibiotic resistance, any recommendation for repeat courses of antibiotic therapy to reduce the need for minor surgical intervention in a not life-threatening disease should be considered inappropriate.
As many readers may have noted , I had been quite concerned about how clinical attachment level (CAL) had been measured in the 2009-2010 continuous NHANES which had been reported in 2012 by Eke et al. (Note: 2011-2012 continuous NHANES has been completed and periodontal results are probably being published soon). After having adopted full-mouth, including 6 sites per tooth, recording and a different case definition, authors had reported quite dramatic higher prevalence of, in particular, moderate periodontitis in the adult population of the U.S. as compared to prevalence reported in NHANES III (Albandar et al. 1999). Another possible amendment was how CAL was calculated.
As for NHANES III, Albandar et al. (1999) had explained the procedure as follows.
The distance from the cemento-enamel junction (CEJ) to the free gingival margin (FGM) and the distance from the FGM to the bottom of the pocket/sulcus were assessed at the mesio-buccal and mid-buccal surfaces. The measurements were made in millimeters and were rounded to the lowest whole millimeter. The assessment was made by using the NIDR periodontal probe. The probing depth was defined as the FGM/sulcus measurement. The CEJ/FGM distance was given a negative sign if the gingival margin was located on the root. Attachment loss was defined as the distance from CEJ to the bottom of the pocket/sulcus and was calculated as the difference between CEJ/FGM and FGM/sulcus distances (or the sum of the 2 distances if FGM was on the root).
Interestingly, Albandar et al. (1999) do not mention recession but rather distances between well-defined landmarks. In contrast, Eke et al. (2012) describe,
All periodontal examinations were conducted in a mobile examination center (MEC) by dental hygienists registered in at least one U.S. state. Gingival recession [= the distance between the free gingival margin (FGM) and the cemento-enamel junction (CEJ)] and pocket depth (PD) (= the distance from FGM to the bottom of the sulcus or periodontal pocket) were measured at 6 sites per tooth (mesio-, mid-, and disto-buccal; mesio-, mid-, and disto-lingual) for all teeth, excluding third molars. For measurements at each site, a periodontal probe (Hu-Friedy PVP 2TM, Chicago, IL, USA) with 2-, 4-, 6-, 8-, 10-, and 12-mm graduations was positioned parallel to the long axis of the tooth at each site. Data were recorded directly into an NHANES oral health data management program that instantly calculated attachment loss (AL) as the difference between probing depth and recession. Bleeding from probing and the presence of dental furcations were not assessed. (Emphasis added.)
Note that Eke et al. (2012) mention “recession” rather than the (signed) distance CEJ/FGM.
Eke et al. later clarified in a letter to the editor of the Journal of Dental Research, Dr. William Giannobile (which was kindly provided to me via email) that the procedures were essentially identical in NHANES III and continuous 2009-2010 NHANES and had actually been adopted for decades. As Drs. Eke et al. wrote to Dr. Giannobile,
The algorithm used to calculate attachment loss (AL) in NHANES can intuitively be misunderstood because it is stated that subtraction measures of gingival recession from measures of pocket depth PD (and not added as one would expect intuitively). However, mathematically this is correct. The recession is called out as a negative number by the examiner and is subtracted from the PD i.e., PD – (-recession) = PD + recession (if the FGM is below the CEJ) which adds up to the sum of the recession plus the PD. If the FGM is above the CEJ, then it is the direct sum of the recession (which is positive) and PD. Thus in NHANES, AL is calculated from three anatomical points versus a direct measure from the CEJ to the bottom of the pocket as may be done clinically (Clinical attachment loss). There is a long history behind why NCHS has used this approach, however this is how AL has been determined for all previous NHANES including NHANES III (the dataset used by Albandar 1999), NHANES 1999-2004 and NHANES 2009 – 2010.
Note that “recession” (from Latin recessus, i.e. “retreat”) cannot reasonably be negative. At least that won’t make too much sense but easily confuses readers and scientists, both within and outside our main professional field. This is, by the way, a lengthy explanation of why a very circumstantial definition of a straightforward and intuitive distance between landmarks, one well- and the other rather ill-defined (see below), may be “mathematically correct” but completely delusive. I am afraid that recent misconceptions about what is clinical attachment loss (see, for instance, my former colleagues’ recent case-control study of periodontal disease in type 1 diabetic children) are mainly due to the confusing description by Eke et al. (2012).
Moreover, common dental recording systems including Tromsø University Dental Clinic’s and Dental Competence Center’s Opus rely on recession (i.e. real gingival retraction) and periodontal probing depths. Attachment levels can not even be recorded. Adding zero retraction to probing depth would not automatically yield attachment loss. Educating undergraduates about attachment loss and, based on that, contemporary case definitions (Page and Eke 2007) is in fact difficult if findings have to be entered into an insufficient recording system. When data are research findings, conclusions might be spurious.