The new AAP guidelines for periodontal disease classification

The new American Academy of Periodontology (AAP) periodontal disease guidelines are all well-intentioned, necessary, very well-thought-out, highly detailed, developed by an erudite group of individuals, confusing, cumbersome, and presently ignored by many dental professionals. To be sure, the need for new classification guidelines is not in dispute.

There is one requirement in particular that, in my opinion, is going to be the point at which many clinicians throw up their hands in frustration and say, “I can’t be bothered with this.” It is percent of bone loss divided by age (% bone loss/age). If this calculation is <0.25, the patient is grade A; 0.25–1.0 = grade B, and >1.0 = grade C.

Think about this for a moment. The clinician is expected to get out a calculator and complete this arithmetic chairside, and then refer to the table to determine the grade level just for that parameter.

So, for a 61-year-old patient with 33% bone loss, % bone loss/age = 0.54, making that patient a grade B. Arriving at this figure without a calculator would be very difficult at best. Next, the clinician needs to evaluate if the periodontal destruction is commensurate with the biofilm deposits, excessive compared to the biofilm deposits, or minimal compared to the biofilm deposits. Then, hope a diabetic patient knows if his or her HbA1c level is more or less than 7.

All of this data is used to determine the rate of periodontal disease progression, which would be a powerful predictor of where this patient’s gums and bone are headed.

There is also the question of how accurately the system predicts disease progression. Periodontal disease comes in many shapes and forms. Think about the patient with the majority of sites at 1–3 mm, a handful of 4 mm pockets, and one 5 mm pocket on the distal lingual of tooth no. 1. If you score the patient according to the worst site as stage II, is that truly representative?

What about the specific periodontal pathogens responsible for each patient’s case of periodontal disease? Of all the risk factors for periodontal disease development and progression—including smoking, diabetes, poor oral hygiene, stress, and immunodeficiency, among others—the most impactful risk factor is the causative bacteria. A patient with one or more of the high-risk pathogens, such as Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, or Aggregatibacter actinomycetemcomitans, is at a higher risk of disease progression. These bacteria are highly pathogenic, associated with aggressive forms of disease, tissue invasive, and capable of causing periodontal disease at lower population levels than other species.

Consider the scenario of a patient who is AAP grade C, which indicates tissue destruction that exceeds expectations given the biofilm deposits. In this scenario, the patient appears to be in a period of rapid breakdown or early onset disease. Wouldn’t identification of the bacteria be important? Of course it would. If the patient’s salivary test identified low levels of less risky pathogens, then some other factor is the primary reason for the excessive degree of periodontal breakdown with low biofilm levels. If the patient is loaded with high-risk bugs, then that is likely the primary factor. In either case, identifying the causative bacteria provides information on which therapeutic approach to take.

It is important to keep in mind the herculean effort it took to bring the protocol to fruition. Equally important is the recognition that it is far easier to critique than create. Kudos to the individuals who completed this work. Let’s hope that going forward something comes along to accelerate implementation of the new AAP guidelines.

Just something to think about.

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