Two dental hygienist explaining x-rays to patient

Periodontitis Classification: All About the AAP's Updates

Nov 20, 2018

Author: Amber Metro-Sanchez

Have you heard about the new classification system that will change the way you rate your patients' periodontal health? A new classification system emerged from the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions, co-hosted by the American Academy of Periodontology (AAP) and the European Federation of Periodontology (EFP). The workshop's classification changes are the first since 1999. This new system covers many factors in order to enable clinicians to form a complete picture of the patient's condition and to diagnose and manage it.

Categories of Periodontal Diseases and Conditions

As detailed in the Journal of Clinical Periodontology, the new classification system identifies three types of periodontal diseases and conditions along with several important subcategories:

  1. Periodontal Health, Gingival Diseases and Conditions: This category includes periodontal and gingival health, gingivitis related to dental biofilm and gingival diseases/conditions not related to biofilm.
  2. Periodontitis: This classification encompasses necrotizing periodontal diseases, periodontitis (no longer identified as chronic or aggressive) and periodontitis as a manifestation of systemic diseases.
  3. Other Conditions Affecting the Periodontium: These conditions include systemic diseases affecting the periodontium, periodontal abscesses or endodontic-periodontal lesions, mucogingival deformities and conditions, traumatic occlusal forces, and tooth and prosthesis-related factors.

How the Staging and Grading System Works

This new classification system has two key components: identifying a stage and a grade of periodontal disease involvement for the patient. The AAP reports this new system "provides a structure for treatment planning and for monitoring a patient's response to therapy."

The stages indicate the severity of the disease at presentation and the complexity of disease management, according to the Journal of Periodontology. The stages range from Stage I to Stage IV, with the lowest number representing the least severe form of the disease. The staging is determined by a variety of factors, including the amount of clinical attachment loss, percentage of radiographic bone loss around the tooth, number of teeth lost due to periodontal disease and probing depth and the complexity of treatment.

Grades indicate supplemental information about the biologic features of periodontitis and incorporate a history-based analysis of the rate of periodontal progression. Grading includes assessment of the risk of further progression, analysis of possible poor outcomes of treatment and assessment of the risk that the disease or its treatment may negatively affect the general health of the patient. The three grades are:

  • Grade A: Slow progression
  • Grade B: Moderate progression
  • Grade C: Rapid progression

These grades are based on clinical attachment level or radiographic bone loss, percentage of bone loss and case phenotype (which is determined by the body's reaction to the presence of biofilm). The grading system also takes into account smoking and hyperglycemia in diabetes as individual risk factors.

How Peri-Implant Diseases and Conditions Are Categorized

In addition to periodontal disease and conditions, the system outlined in the Journal of Clinical Periodontology includes four new categories for peri-implant conditions and diseases. According to the American Academy of Implant Dentistry, 3 million people in the U.S. currently have dental implants and the number is increasing by 500,000 annually. It is necessary to integrate information about implant complications, and these are organized in four categories under the new classification scheme:

  1. Peri-implant health: A lack of visible inflammation and no bleeding upon probing
  2. Peri-implant mucositis: Bleeding on probing and visible signs of inflammation
  3. Peri-implantitis: Inflammation of peri-implant mucosa followed by progressive loss of surrounding bone
  4. Hard and soft tissue implant site deficiencies: Deficiencies of the alveolar ridge caused by natural healing, extraction trauma, infections or a variety of other factors affecting hard and soft tissue

How Will the New System Change Patient Care?

As explained by the AAP, this new classification system will help clinicians develop a well-rounded treatment strategy based on a patient's specific needs. This system enables dental professionals to individualize patient treatment more thoroughly by providing significantly more detail than the previous classification system.

The new periodontitis classification system may also help you explain to your patients how their health behaviors and conditions affect their oral health. Use the categories and stages to talk to your patients about the expected progression of their periodontal disease, which will hopefully motivate them to improve modifiable risk factors such as A1C levels for diabetics or to remove others such as cigarette smoking.


  • Unlike the old scheme, the new periodontitis classification system addresses peri-implant diseases and conditions.
  • Staging and grading of periodontal disease are essential elements of the new classification scheme.
  • A more detailed periodontal and peri-implant diseases and conditions classification scheme will allow you to integrate risk factors like smoking and the body's response to biofilm into the patient's periodontal diagnosis and expected disease progression.

Why It's Important

This new classification system will allow dental hygienists to individualize patient periodontal care and address multi-dimensional factors, with the potential to improve outcomes in patients' oral health.

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