Technically Speaking: Tips for Implementing the 2018 AAP Periodontal Classification (Part 8)

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.

In reference to the ‘reduced periodontium’ have there been any changes from the 1999 to 2018 AAP Periodontal Classification?
Yes, and here’s what you need to know. In the 1999 AAP classification, the term “reduced periodontium” referred to a periodontium that was reduced in a successfully treated, stable periodontitis patient. The 2018 AAP classification recognizes this type of periodontium, but it also recognizes that there is another type of “reduced periodontium” that exists due to non-periodontitis causes. In fact, the 2018 AAP recognizes three types of periodontium (Table 1) and has included them in the Periodontal Health, Gingival Diseases and Conditions category.

How does the newest classification define the parameters of health, gingivitis, and periodontitis?
Understanding health and disease parameters makes it possible for clinicians to develop extremely specific, measurable client-centred goals that can easily be communicated to patients. To provide optimal care, familiarize yourself with the following AAP benchmarks:

1. Intact Periodontium
• Health – ≤3mm PD
and <10% BOP
• Gingivitis – >3mm PD
and ≥10% BOP

2. Reduced Periodontium on a non-periodontitis patient (note parameters of health and disease are the same as an Intact Periodontium)
• Health – ≤3mm PD
and <10% BOP
• Gingivitis – >3mm PD
and ≥10% BOP

3. Reduced Periodontium in a successfully treated, stable periodontitis patient
• Health – 3–4mm PD
and <10% BOP plus no 4mm PD
or greater that BOP
• Gingival Disease (gingivitis)
– 3– 4mm PD and ≥10% BOP
on 3mm PD only.
No 4mm PD that BOP.

Table 1

Since periodontitis and gingivitis are different periodontal conditions, the parameters of health for a successfully treated and stable patient are also different so as to prevent overtreating of periodontitis patients.

Typically, patients younger than 32 with a) reported history of ortho, extractions, open contacts, and so on, b) no history of diabetes or smoking, and c) where grade C periodontitis has been ruled, will more than likely have a reduced periodontium due to non-periodontitis cause. The parameters of health and disease will easily be determined as set out by the AAP guidelines.

The challenge comes when there is a reduced periodontium due to a combination of periodontitis and reported or identified non-periodontitis cause(s), typically found in the patient 32 years of age and older. This is when critical thinking is required to identify parameters of health and diseases as set out by the AAP guidelines.

How do we know when a successfully treated periodontitis patient is no longer stable and we have a ‘recurrent’ or progressive disease state?
To determine a recurring or progressing state of periodontitis, one must first understand what health looks like. Health in a successfully treated periodontitis patient is 3-4mm PD, <10% BOP, and no 4mm PD bleeding.

If the patient has 3-4mm PD, ≥10% BOP but still no 4mm PD bleeding, he or she has gingivitis on a successfully treated periodontitis periodontium. If bleeding exists on 4mm PD or greater, than the patient has recurrent or progressing periodontitis.


  1. 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.
  2. Lang NP, Bartold PM. Periodontal health. J Periodontol. 2018;89(Suppl 1): S9–S16.
  3. Chapple ILC, Mealey BL, et al. Periodontal health and gingival diseases and conditions on an intact and a reduced periodontium: Consensus report of workgroup 1 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. J Periodontol. 2018;89(Suppl 1):S74–S84.

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 through her work as a public speaker, consultant, educator, and business coach for forward-thinking dental practices. Gabriele can be reached at or visit