What Counts and What Does Not: 2018 AAP Periodontal Classification
As dental professionals have implemented the 2018 AAP periodontal classification of staging and grading there is still some confusion as to some of the rules of what counts and what does not count. One of the ways to make sense of the ‘rules’ is to ask the question Papapanou et al. (2018) pose in the Journal of Clinical Periodontology, “How do we define a patient as a periodontal patient?” (p. 168). Answering this question clarifies the rules of staging and grading, including the need to capture true interdental CAL’s, the requirement for a matching CAL site, searching for the highest CAL’s, why adjacent CAL doesn’t count, when buccal and lingual CAL can be considered, and how periodontitis distribution is assessed across the entire mouth rather than assigning generalized or localized labels to specific stages.
To answer this question, we must consider how we have traditionally approached it and not ask "Does the patient have perio?" instead "How do we define a patient as a perio patient?" The difference lies in the depth of analysis and clinical significance, with the latter requiring a more precise and standardized assessment. “Does the patient have perio?” This is a yes/no question that assumes a simple answer based on clinical findings. The ‘old’ classification leaned more towards a yes/no approach, hence why AAP saw the need for change. It may not take into account disease staging, progression, or individual risk factors. Although clinicians were diligent in making notes on these elements, the old system did not connect and intertwine these as easily. The answer could be misleading if it only considers current symptoms without historical data or risk assessment. For example, the number of teeth loss to periodontal disease now being accounted for in the 2018 AAP periodontal classification version.
“How do we define a patient as a perio patient?” This is a more critical and clinically relevant question because it requires an evidence-based, structured approach, considering Stage & Grade of the disease, CAL, radiographic bone loss, teeth loss to periodontal disease, risk factors (e.g., smoking & diabetes), etc. This question leads to better treatment planning and prognosis determination. It helps in long-term disease management, including maintenance and risk factor modification. It aligns with evidence-based approaches, ensuring that periodontal classification is used consistently from one clinician to the next.
So, what counts and what doesn’t?
- Interdental CAL as the Primary Indicator
According to AAP guidelines, interdental clinical attachment loss (CAL) is the primary reference for staging periodontitis, not probing depths. Some offices default to probing due to a lack of GM charting, which is a quality control issue rather than an interpretation of AAP guidelines. For years I taught a course titled ‘Where the Heck is the GM’, although important, other speakers were focused on the theory of the new periodontal system, however, I saw where on the clinical ground floor the GM was the stopper. Many RDH and DDS do not know where the heck the GM is because it’s a new shift from the previous AAP system update where CAL’s were introduced as the deciding factor of periodontal classification not the unreliable unfixed points within probing (yes there were two updates from AAP). This change introduced the ‘charting’ of inflammation and health not just recession. Highlighting all along why periodontal odontograms have a coinciding box to each sulcus depth value labelled as the GM line in the software program. Furthermore, it is not ‘okay’ to bypass these boxes in the GM line or simply default to assigning a ‘0’ value. Paint yourself a mental image, a ‘0’ CAL has no papillae as the GM is at the CEJ. So, when a ‘0’ is charted in every box except the middle box, the chart is displaying no papillae! - Non-Adjacent CAL and the Need for a Match
To diagnose periodontitis, CAL must be present on two or more non-adjacent teeth to rule out localized trauma or other non-periodontal causes. - Why Not Count Buccal/Lingual CAL Automatically?
Buccal and lingual CAL can only be included if due to periodontitis, not trauma, anatomy, or occlusal factors. AAP states that occlusal trauma does not initiate periodontitis, despite clinical assumptions. The criteria to ‘count’ is buccal or lingual CAL of ≥3mm with a probing depth of ≥3mm at two or more teeth (not due to trauma, decay, frenum pull, class V resto, any resto, etc.). - Generalized vs. Localized Periodontitis
The AAP classification system defines periodontitis at the whole-mouth level, not by mixed-stage severity. The highest stage of loss dictates the case classification, we are picking the worse area (two areas with a match). For example, a case with Stage I, II, and III teeth would be classified as generalized Stage III periodontitis as it encompasses all stages. Localized periodontitis applies only if less than 30% of teeth are affected. Paint yourself another mental image, what does this look like? It’s the perio odontogram that has many CAL’s of ‘0’ and less than 30% of the teeth have a CAL of 1 or above. Are you thinking, this is not commonly seen? Correct. Why? Because periodontitis is a chronic disease. - What about RBL and the CEJ?
This needs to be discussed from an anatomical perspective in remembering the crestal area of the alveolar bone in health does not sit at the CEJ. Stressing again, in health, it is 0.5-2.0 mm apical to the CEJ. As such this brings about another debate, should clinicians measure RBL from the CEJ or slightly lower because the alveolar bone was never at the CEJ to begin with!
Interpretations of the new system vary, but over and under staging should be avoided, or worse no staging and grading. Teams should calibrate regularly to maintain consistency and ensure quality client care. This background information is the base as to why there are ‘rules’ of what counts and what does not count. This is the most confusing part of the classification system but look at you now the AAP guru having tackled this puzzle piece!
Reference:
Papapanou, P. N., et al. (2018). Periodontitis: Consensus report of workgroup 2 of the 2017 World Workshop on the Classification of Periodontal and Peri‐Implant Diseases and Conditions. Journal of Clinical Periodontology, 45(S20), S162-S170. https://doi.org/10.1111/jcpe.12946
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Michelle Aubé (Simmonds) RDH, maxill Dental Hygiene Educator
Michelle is a Dental Hygiene Speaker, Consultant and Educator with over 30 years of experience as a RDH and 4 years as a CDA. She is a professor and curriculum writer at Fanshawe College in both the dental hygiene and continuing education program sharing her knowledge in IPAC, professional practice, periodontal classification, social justice, advocacy and clinical applications. She is maxill's CE and IPAC Director and wears various IPAC hats including auditing federal correctional facilities dental clinics for IPAC standards. Michelle is ODHA's Regional Board Director and authors articles for CDHA's OH Canada professional publication and continues to practice clinically in London ON. She is a CDHO IPAC Remedial Facilitator and IPAC Expert Opinion. Her strong ethics has allowed her to serve on the Discipline Committee at Algonquin College and hold the position of a CDHO Quality Assurance Assessor for 7 years. As a lifelong learner she is completing a BA in Adult Education at Brock University. Her diverse dental background and current status as a practicing RDH offer a fulsome and realistic view of dental-related topics. As a passionate champion for the profession, she advocates for equity, professional autonomy, and systemic change, true grassroots leadership at its finest.
Michelle can be reached at michellea@maxill.com
