Periodontitis Staging and Grading

by Beth Ryerse, RDH

We are being challenged every day to grow as professionals. It is often difficult to keep up with all of the new information that seems to bombard us. The necessity of oral cancer screening, routinely, on a younger demographic. Infection Prevention and Control guidelines that must be implemented. The impact on oral health that the legalization of cannabis will have. Pre-med requirements. Elder Abuse and how to respond when we see signs of it in our treatment room. MeToo in the workplace. Periodontal disease associated with a myriad of other afflictions. And so much more.

Maintaining professionalism when faced with ever-changing information is a daunting task. Each one of the topics mentioned above deserves investigation to ensure that we are provided true best-practice, based on current knowledge.

In this article we will focus on the disease that we deal with on a daily, often hourly, basis. There is exciting news on this front.

Fortunately, we have recently been presented with new classifications for periodontal disease which will clarify diagnosis and therefore, treatment protocols. This is cause for celebration!

The 1999 Periodontal Classifications, were structured as (broad categories only here):

  1. Gingival Diseases:
    Dental plaque induced gingival diseases
    Non-plaque induced gingival lesions
  2. Chronic Periodontitis
  3. Aggressive Periodontitis
  4. Periodontitis as a Manifestation of Systemic Diseases
  5. Necrotizing Periodontal Diseases
  6. Abscesses of the Periodontium
  7. Periodontitis Associated with Endodontic Lesions
  8. Developmental or Acquired Deformities and Conditions

For some, the many sub-categories within each of these headings, seemed to complicate an already difficult disease and it was not always beneficial in helping to determine a diagnosis and an appropriate treatment plan.

In 2016, the Canadian Journal of Dental Hygiene published an article titled, “Current status of the classification periodontal diseases” .¹ In this paper, the authors point out that a World Workshop in Clinical Periodontics was planning to meet in November 2017. The focus would be the limitations of the existing periodontal classifications, including clinical attachment levels (CAL) as main classification criterion, distinguishing between aggressive versus chronic, and localized versus general periodontitis. The task force involved in this meeting wanted to include additional parameters (beyond CAL) such as inflammation, bleeding on probing, increased probing depths and radiographic bone loss.

Often times as clinicians, using only CAL as the main classification criterion, left us unsettled. We know so much more about this disease than we did in 1999.

What we know about periodontal disease and the best methods of treatment continues to evolve. The classifications in 1989 were an advancement over what was available before that time. The 1999 groupings were a significant improvement over that. Now, we have ‘Stages’ and ‘Gradings’ to further our commitment to better diagnosis and treatment of this disease.

The World Workshop was held as planned in November 2017, with expert participants that included members of the American Academy of Periodontology (AAP) and the European Federation of Periodontology (EFP). The purpose of the workshop was to review new technology, research and information with the goal of creating revised periodontal classifications. The results of that workshop are these new AAP guidelines that were announced in June 2018.

You may want to print some of these documents out and have them laminated to use as chairside resource tools. The information they contain will be a valuable asset to client education. They can be found in printable version at:

This introductory paper provides an overview and is a good place to start with this new information.

The steps and staging and grading will make consistent diagnosis, easier. It will also help clients to understand when we are communicating that diagnosis. The new classifications present periodontitis in much the same way that other diseases are categorized, as stages. Most people are familiar with the concept that Stage IV cancer is more serious than Stage I. The same is true for periodontitis.

The “Three Steps to Staging and Grading a Patient” include:
Step 1: “Initial Case Overview to Assess the Disease” – then using the findings from this assessment you determine the ‘stage’ of disease.
Step 2: “Establish Stage” – divided into two sections “mild to moderate” and “moderate to severe”. Then, to address severity, complexity and extent and distribution of periodontitis, you assign a ‘grade’.
Step 3: “Establish Grade” – focus on client characteristics and risk factors, systemic influences and evaluation from previous treatment(s).

Three Steps to Staging and Grading a Patient - Periodontitis

The four stages of periodontitis are based on the amount of damage that has already occurred. The factors measured include: interdental clinical attachment loss, radiographic bone loss, tooth loss and probing depths for Stage I and II. Additionally, furcation involvement, ridge defects and bite collapse are involved in Stages III and IV.

The ‘Grading’ portion of the new classification system allows us to incorporate other indicators of disease in order to determine how much risk a client has for further progression of periodontitis.

The “Primary criteria are bone loss or CAL, age, case phenotype and biofilm deposits. Grade modifiers include smoking and diabetes. For example, a client could have Stage III which indicates damage so there has been previous active disease. They are a Grade A though, now in ‘remission’ so the risk of progression is low. This client would obviously need different therapy than one who was Stage III, Grade C.

As we continue to learn about the causes of periodontal disease and the many associations with systemic health and wellness, the experts will undoubtedly be required to provide further revisions to these classifications in the future.

Staging and Grading Periodontitis Periodontitis Grading

As healthcare professionals, it is our responsibility to stay current with the results of the research that is being done. However, if we only read about the developments and do not put that new knowledge into practice, the only ones to benefit are ourselves.

I would encourage you to become familiar with the documents from the AAP and feel confident in your knowledge of the four stages of periodontal disease. Be able to discuss the implications of the severity, complexity, extent and distribution of each stage, in client terms. Then you will be able to educate your client in a manner that is clear and understandable for them. That will, in turn, lead to acceptance of the therapy protocol that is truly required.

When a client has a clear understanding of their disease and the potential for further destruction, they are better equipped to make the best decision for their own health. That is where the grading system offers such significant help. The ability to connect risk factors to the rate of periodontitis progression, using the chart as a guide, allows us to ‘paint a picture’ that is specific to particular client characteristics.

True quality assurance means that we not only investigate new concepts, skills and technology but actually adapt our practice to include current, evidence-based knowledge so that we are always striving to provide best practice.


  • Canadian Dental Hygienists Association –
  • Can J Dent Hyg 2016;50(3): 140-144
  • American Academy of Periodontology –
  • The American Academy of Periodontology. Proceedings of the World Workshop in Clinical Periodontics. Chicago: The American Academy of Periodontology; 1989:I/23- I/24

Tables from Tonetti, Greenwell, Kornman.
J Periodontal 2018;89 (Suppl 1): S159-S172.

About the Author
Beth Ryerse has been actively and meaningfully involved with the dental hygiene profession for more than 30 years. Her passion for her career has led to a depth of experience and accumulated knowledge gained through; clinical experience, educating, lecturing, consulting, authorship and mentoring. She is an active member in provincial and international dental hygiene associations, is the elected CDHA Ontario Board Director, a key opinion leader and a certified soft-tissue diode laser trainer.

Beth is an engaging, enthusiastic, dynamic professional educator who has fun when she interacts and takes joy in growing with her peers in their commitment to
life-long learning.

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