Review of Updated Periodontal Classifications for Personalized Patient Care

Meaningful changes have taken place in the field of periodontics. Before the 2018 publication of the proceedings from the 2017 World Workshop on the Classification of Periodontal and Peri‐Implant Diseases and Conditions,¹ periodontal classification had been the same for almost 20 years. The guidelines had not been updated since 1999, so arriving at these new classifications was a significant achievement. The updates resulted from workshops conducted in 2017 by the American Academy of Periodontology (AAP) and the European Federation of Periodontology (EFP). Together the agencies reviewed papers, articles, publications, and reports to develop guidelines leading to the reclassification of the current terminology of periodontal disease.^2,3

In the 1999 guidelines, periodontitis had been classified as chronic, aggressive (localized or generalized), necrotizing, or showing a manifestation of systemic disease.^2,4 According to those classifications, chronic and aggressive periodontitis were considered to manifest as different diseases. However, since then research has found that specific and distinct biologic features between the two diseases could not be documented (chronic types of disease microbes versus aggressive types of disease microbes). Each type of microbe is different: some are anaerobic, some aerobic; some Gram-positive, others Gram-negative.³

Under the new classifications, the diseases have been regrouped under the same term, periodontitis.^1,2 This new system will assist dental professionals in diagnosis and treatment of periodontitis by supporting a more intricate view of periodontitis, incorporating severity, tooth loss due to periodontitis, and complexity of management of the patient's periodontal and overall oral rehabilitation needs.^3,5,6

A system of staging and grading, similar to other fields in medicine, is incorporated to promote a multidimensional and personalized approach to diagnosis and treatment.³ The goal of staging is to classify severity based on measurable factors and to assess the complexity of controlling current disease and managing it long term. Grading is focused on risk, progression, and impact on systemic health, to guide therapy and monitoring. The availability of consistent guidelines will improve collaboration and communication, diagnosis, and treatment results.

In addition to periodontitis, the revised classifications include two other categories: Periodontal Health, Gingival Diseases and Conditions (for example, gingivitis and conditions related to biofilm), and Other Conditions Affecting the Periodontium (for example, systemic diseases and traumatic occlusal forces).

Periodontitis Reclassified

Under the new system, periodontitis has been reclassified under a series of stages and grades. Stages 1 through 4 are now described as follows.³

• Stage I periodontitis (mild disease): Patients will have probing depths less than or equal to 4 mm, clinical attachment loss (CAL) less than or equal to 1 to 2 mm, radiographic bone loss (RBL) less than 15% (coronal third), and horizontal bone loss; they will need nonsurgical treatment. They are not expected to have posttreatment tooth loss, so the case has a good prognosis for the maintenance phase.
• Stage II periodontitis (moderate disease): Patients will have probing depths less than or equal to 5 mm, CAL less than or equal to 3 to 4 mm, RBL of 15% to 33% (coronal third), and horizontal bone loss; they also will need surgical and nonsurgical treatment. Again, they are not expected to have posttreatment tooth loss, so the case has a good prognosis for the maintenance phase.
• Stage III periodontitis (severe disease): Patients will have probing depths greater than or equal to 6 mm, CAL greater than or equal to 5 mm, and RBL extending to the middle third of the root and beyond. They may have vertical bone loss and/or furcation involvement of class II or III. Patients in this stage will require surgical and possibly regenerative treatments. There is a possibility of tooth loss of one to four teeth. Implant and/or restorative treatment will be more complex, and the patient may require multispecialty treatment. The overall case has a fair prognosis for the maintenance phase. 
• Stage IV periodontitis (very severe disease): Patients will have probing depths greater than or equal to 6 mm, CAL greater than or equal to 5 mm, and RBL extending to the middle third of the root and beyond. They also may have vertical bone loss and/or furcation involvement of class II or III. They may have fewer than 20 teeth; tooth loss of five or more teeth is possible. These patients will require advanced surgical treatment and/or regenerative therapy, including augmentation treatment for implant therapy; implant and/or restorative procedures are likely to be very complex and will often involve multispecialty treatment. The overall case has a questionable prognosis for the maintenance phase. 

In conjunction with these stages, the new classifications include a grading system. Grading determines the likelihood of posttreatment disease progression. It is loosely based on previous clinical studies from private practices that classified posttreatment tooth loss. The designations recommended are A, B, or C, signifying slow or no progression, moderate progression, and rapid progression, respectively. The assessment is based on past progression, presence of risk factors such as diabetes and/or smoking, and the systemic impact of periodontitis.³

After the stage and grade are determined, they become the guiding factors for treatment, prognosis, and expectations during maintenance therapy. For example, if a patient is a smoker and also has diabetes, these two risk factors would be considered because they impact healing and progression of disease-treatment is determined based on more than just pocket depths. Treatment is now considered based on the whole condition of the patient. During the periodontal maintenance process, the clinician may need to address why tissue and bone may not be healing and why there has not been improved attachment. Considering risk factors, as specified in the AAP's new "Three Steps to Staging and Grading a Patient," allows practitioners to include information that presents an overall view of the patient rather than a narrowly targeted version. Overall health and risk factors are now included.³

In the published proceedings of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions, the following is stated: "The diagnosis could be divided into severity levels in different parts of the mouth. For example, a patient might have generalized moderate chronic periodontitis with localized severe periodontitis."³ The situation described is commonly seen in the field. Periodontists make an effort to save teeth by saving the bone through preserving tissue and killing the specific types of bacterial microbes that exist. In the last several decades, however, it has been confirmed that a diagnosis based on severity alone gives an overly simplified view of a very complex disease. By allowing for more complexity, the new system is a considerable improvement over the 1999 method. Now the severity of disease as it exists in different areas of the mouth can be diagnosed. Under the previous method, a clinician would look at the worst overall area and diagnose the disease as one specific type. Now, one patient alone can have a generalized moderate chronic periodontitis in one area of the mouth and localized severe periodontitis in another. Being able to add more to a diagnosis is one of the main improvements of the new classification system.³

Patient Example Diagnoses

Here is an example of how the staging and grading criteria can be applied: In determining staging, it is observed that a patient has several areas in the mouth where there are concerns. The patient is diagnosed as stage II in the upper right area of the mouth, where there is between 3 and 4 mm of pocket depth. In that same quadrant (upper right), the grading may be grade A. Even though the patient is a smoker and has heavy plaque in that upper right quadrant area, there has been no bone loss for more than 5 years. So, the upper right quadrant is diagnosed as stage II, grade A. Next, the lower left quadrant could be heavily involved with bone loss, carry both vertical and horizontal bone loss, and be diagnosed as stage III, grade B. Under the staging criteria, this diagnosis would indicate that the lower left quadrant would have greater than 5 mm of pocket depths, moderate bone loss, and possible mobility. Then, under the grading criteria, it may have been noted that the patient has diabetes, is a smoker, and has heavy biofilm and moderate amounts of subgingival mineral deposits. This example shows that one patient can have more than one diagnosed concern in the same mouth.

By following both the staging and grading criteria, patients can be specifically diagnosed in each area of the mouth for respective bone and tissue concerns. Previously, just the area with the most damage or issues would be considered, and the patient would be diagnosed with, perhaps, moderate generalized chronic severity even if just one area were affected, such as the lower left. Now, with better criteria, patients can be diagnosed with different concerns in different areas.

Another important difference is that staging can now change for a patient. Stages do not typically regress to a lower stage. For example, if a patient has been treated and is now clinically stable, that patient can be described as having periodontal stability. If, during a periodontal maintenance visit, sites present greater CAL, greater RBL, and deeper probing depths, the patient would then have an unstable case of recurrent periodontitis. The stage could change to a higher level depending on the presenting criteria, such as loss of more teeth, expanding furcation involvement, or radiographic bone changes such as horizontal or more local vertical areas of bone loss.³

It is also noted that although patients with periodontitis can be treated and improvement can be achieved, they may still require some degree of maintenance. Reattachment may occur and poor oral healthcare habits may be overcome, but there may be continued potential for bone loss and increased pocket depths, and risk factors such as systemic diseases are likely to keep a patient under periodontal maintenance.³

Peri-Implant Disease

A new classification system for peri-implant diseases was also developed at the World Workshop. Peri-implant health was classified as an absence of visual signs of inflammation and bleeding on probing. Conversely, peri-implant mucositis was defined as bleeding on probing and visual signs of inflammation. Peri-implantitis was characterized as a plaque-associated pathologic condition in the tissues surrounding dental implants that may follow peri-implant mucositis, with inflammation in the peri-implant mucosa and progressive loss of supporting bone. The new classifications also described peri-implant soft- and hard-tissue deficiencies that may result from tooth loss or other factors.^2,7

Importance for the Dental Hygienist

With knowledge of the new guidelines and an understanding of the staging and grading criteria for periodontal disease, dental hygienists can further evidence-based care. A more detailed periodontal and peri-implant diseases and conditions classification scheme will aid hygienists in leveraging their knowledge in their expanding scope of practice because they can individualize patient care in consideration of multi-dimensional factors.

For example, in a study designed to explore dental hygienists' experiences diagnosing periodontal disease in clinical practice, the authors found that dental hygienists claimed that the lack of a standardized periodontal classification system undermined communication among healthcare providers.⁸ At the time of the study (before the new system), four different classifications were in use by the respondents: 1986 American Dental Association/AAP Periodontal Case Types; 1986 AAP Classification System; 1989 AAP Classification System; and the 1999 AAP Classification System. In conclusion, they identified a future area of research on the evolving periodontal disease diagnostic terminology focusing on the impact of the 2017 classification guidelines.

The authors also noted that "more than half of the participants in this study reported being responsible for the diagnosis of PD [periodontal disease] in their clinical practice setting. It is noteworthy that none of the participants resided in a state where diagnosis of PD is part of the scope of practice."⁸

Dental hygienists are increasingly positioned to assess periodontal condition, not only in clinical practices, but also as they move into other settings, such as senior residential care facilities. Declining edentulism among this population requires dental hygienists to identify, prevent, and treat periodontal diseases.^9,10

Conclusion

Continuing research into oral health conditions, along with new models of dental practice, is accelerating dental hygiene's expansion into more complex and personalized patient care. With the new classifications of periodontology involving the staging and grading of patients, patients can be classified with a greater accuracy and diagnosis of their oral health. Oral health practitioners can integrate risk factors such as smoking and the body's response to biofilm into the patient's periodontal diagnosis and expected disease progression, integrating both medical and dental care and playing a vital role in community health.

About the Author

Randy R. Terry, BS, RDH, is a national lecturer on paramedic courses, dental hygiene, pharmacology, pathology and oral health, and systemic disease.

References

1. Kornman KS, Tonetti MS, eds. Classification of periodontal and peri-implant diseases and conditions. J Periodontol. 2018;89(suppl 1):S1-S318.

2. Caton JG, 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 Periodontol. 2018;89(suppl 1):S1-S8.

3. American Academy of Periodontology. Proceedings from the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. https://www.perio.org/2017wwdc. Accessed December 18, 2019.

4. 1999 International Workshop for a Classification of Periodontal Diseases and Conditions. Papers. Oak Brook, Illinois, October 30-November 2, 1999. Ann Periodontol. 1999;4(1):1-112.

5. 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. [Erratum in: Corrigendum. J Periodontol. 2018;89(12):1475.]

6. Papapanou PN, Sanz M, Buduneli N, et al. Periodontitis: consensus report of workgroup 2 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. J Periodontol. 2018;89(suppl 1):S173-S182.

7. Berglundh T, Armitage G, Araugo MG, et al. Peri-implant diseases and conditions: consensus report of workgroup 4 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. J Periodontol. 2018;89(suppl 1):S313-S318.

8. French KE, Perry KR, Boyd LD, Giblin-Scanlon LJ. Variations in periodontal diagnosis among clinicians: dental hygienists' experiences and perceived barriers. J Dent Hyg. 2018;92(3):23-30.

9. Hopcraft MS, Morgan MV, Satur JG, Wright FA. Utilizing dental hygienists to undertake dental examination and referral in residential aged care facilities. Community Dent Oral Epidemiol. 2011;39(4):378-384.

10. Haumschild MS, Haumschild RJ. The importance of oral health in long-term care. J Am Med Dir Assoc. 2009;10(9):667-671.