August 27, 2021
 by Gabriele Maycher, CEO, GEM Dental Experts Inc. BSc, PID, dip DH, RDH.

Still confused about the 2018 AAP Periodontal classification? Never fear! The next few monthly columns will review some of the most important updates made to the industry’s global periodontal guidelines to help hygiene teams achieve the highest level of care. Once we have exhausted this topic we will move onto other questions about the process of care. If you have any specific questions, you would like answers to, please let me know.

Q: Most of my patients are either Grade B or Grade C. I don’t seem to have any that fall into the Grade A category. Why?


A: There are a couple of reasons why initially it will be difficult to score a patient as Grade A. Reason No. 1 is that unless you have a previous set of periapicals (PAs) or a full-mouth series (FMS), it will be difficult to use direct evidence (i.e., longitudinal observation available in the form of older diagnostic quality radiographs)as a comparison to determine Grade A, which is defined as no bone loss over five years. Also, using indirect evidence (i.e., % bone loss / age) would mean that the patient would have to be Stage I, <15% bone loss and at least 60 years old to score a Grade A (i.e., 14% bone loss / 60 years of age = .23). Few patients fall in the category of Stage I because it’s difficult to assess such a small amount of change using clinical attachment loss (CAL) or radiographic bone loss (RBL).

So, at best, you should assume Grade B (<2mm over five years and destruction commensurate with biofilm deposits) at least until you have direct evidence in the form of a previous FMS or a set of PAs as a measure of actual progression. If the patient has risk factors that may accelerate disease progression (i.e., smoking and/or diabetes) then you may shift the grade score to a Grade C independent of direct and indirect evidence.1


  1. Tonetti MS, Greenwell H, Kornman KS. Staging and grading of periodontitis: Framework and proposal of a new classification and case definition. J Periodontol. 2018;89(Suppl 1):S159– S172.

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