January 22, 2021

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

As seen in Oral Health Hygiene Magazine. 

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: Are the terms “Chronic and Aggressive Periodontitis still used in the new global 2018 AAP Periodontal Classification?

A: No; the new global classification no longer uses or references these classifications, essentially collapsing the two classifications into one called “periodontitis” under the category of Periodontitis (Table 1).

Longo, A. B., Ward, W. E., & Fritz, P. C. (2018, October 16).

However,  it’s still important to understand the characteristics of these former periodontal classifications, as they help us identify and classify periodontitis under the new guidelines. Let me explain.

The American Academy of Periodontology (AAP) found that neither of these conditions has a unique pathophysiology or causation. However, the AAP did recognize that each are a “complex interplay of risk factors in a multifactorial disease model,” which explains why we see variations in clinical presentation in terms of age, severity, and progression rate.

For example, when you consider the extent of disease, chronic periodontitis presented itself more localized and generalized while aggressive periodontitis tended to be present in the molar and incisor area. This is the reason why a molar/incisor pattern distribution was added along with localized and generalized to the “extent and distribution” category in the new classification (Table 5).

Longo, A. B., Ward, W. E., & Fritz, P. C. (2018, October 16).


The words “chronic” in Chronic Periodontitis by definition means that it takes a long time to develop, so typically it would present itself in people over the age of 30. Conversely, when the onset of disease presented itself at puberty or under 30 years of age, we considered the disease process aggressive and categorized it as Aggressive Periodontitis.

Another way to think about chronic versus aggressive is in the progression of disease.

Chronic periodontitis, known to progress at a fairly slow to moderate rate, which can be anywhere from no bone loss to less than 2mm over five years, while aggressive periodontitis was known to be rapid, typically greater than or equal to 2mm over five years.

The great thing about the AAP’s newest model of staging and grading is that it accommodates these clinical variations. Patients formally identified with “chronic periodontitis” will mostly be categorized as Grade B to accommodate the slow to moderate progression and an age of 30 years and older. Patients formally identified with “aggressive” will be categorized as Grade C to accommodate the rapid rate of progression and age range of puberty and less than 30 years of age (Table 6).

Longo, A. B., Ward, W. E., & Fritz, P. C. (2018, October 16).

If, for example, a patient meets the criteria of periodontitis and he or she is less than 30 years of age, does not smoke, does not have diabetes or any other systemic factors, but has generalized moderate bone loss, the diagnosis would be Generalized Periodontitis, Staged II, Grade C, which was formally known as Generalized Aggressive Periodontitis. Or if bone loss is localized to molars and incisors, the diagnosis would be Molar/Incisor Pattern Periodontitis, Stage II, Grade C, which was formally known as localized Aggressive Periodontitis.

So, while we no longer use the terms chronic and aggressive periodontitis in the new classifications, the characteristics of chronic versus aggressive will continue to guide our diagnoses, the grade of progression and help us better track patient outcomes (Table 7).


  1. Longo, A. B., Ward, W. E., & Fritz, P. C. (2018, October 16). The New Global Classification System for Periodontal and Peri-Implant Diseases: An Executive Summary for the Busy Dental Professional. Retrieved from https://www.oralhealthgroup.com/features/the-new-global-classification-system-for-periodontal-and-peri-implant-diseases-an-executive-summary-for-the-busy-dental-professional/
  2. Caton J, Armitage G, Berglundh T, et al. A new classification scheme for periodontal and peri-implant diseases and conditions – Introduction and key changes from the 1999 classification.  J Clin Periodontol. 2018; 45(Suppl 20): S1-S8. https://doi.org/10.1111/jcpe.12935
  3. Tonetti MS, Greenwell H, Kornman KS. Staging and grading of periodontitis: Framework and proposal of a new classification and case definition. J Periodontal.2018;89(Suppl 1):S159-S172. https://doi.org?10.1002/JPER.18-0006

About the Author

A passionate educator with 30+ years of clinical and business experience, Gabriele has revolutionized the way practices optimize client outcomes, growth, and revenue through her consultancy company, GEM Dental Experts Inc. A former practice owner, published author, dental hygiene program director, quality assurance program assessor, entrepreneur of the year, and thought leader for Crest and Oral B, Gabriele shares her innovative views on dental hygiene though her work as a public speaker, consultant, educator, and business coach for forward-thinking dental practices.  Gabriele can be reached at gem@gemdentalexperts.com or visit www.gemdentalexperts.com.

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