The 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions resulted in a new classification of periodontitis characterized by a multidimensional staging and grading system.
Intro
The new guideline has replaced the 1999 periodontal classification which was widely used for 20 years. Yet dental cinicians still find this new staging and grading classification system difficult to apply in daily practice.
Staging Periodontitis?
I was an oral maxillofacial surgeon. And it is quite familiar for me to use cancer Staging system to describe the extent of a cancer in a patient's body. The T-N-M system basically is based on the size of Tumor ("T"); whether it has spread to nearby lymph Nodes ("N"), and if it has Metastasized, spread out distantly to other parts of the body ("M"). This TNM system actually helps to determined the best treatment course and also to predict the prognosis or outcomes of the cancer. Oral surgeons all know about that. If a gingival cancer has cortical bone invasion (T4a), then a wide excision and marginal bone resection has to be done. If there is one ispilateral lymph node, less than 3cm invasion (N1), mostly we do selective neck dissection... something like that. We make surgical treatment or radiation, chemo plan based on different T, different N, and different M. While cancer Grading system classifieds cancer in a microscopic scope, based on how well or how bad the differentiation of cancer cells that can be seen under miscroscope.
But, after years of practicing cancer staging and grading system in the field of oral and maxillofacial surgery, I went to the Periodontal & Implant residency in 2019, when the "New periodontitis classification" was just released. Dental schools and periodontists all over the world are eager to teach and adopt this new system to classify gum disease.
This new periodontitis classification really annoyed me at that time. Because it doesn't really change the modality of treatment or tooth prognosis based on "staging" or "grading". For example, if patient A is diagnosed to have stage 2 periodontitis, and patient B is have stage 3 periodontitis, we can't really say patient B needs periodontal treatment different thatn patient A, neither can we say patient B would lose his teeth faster or more than patient A. You know what I mean?
Then, in that case, what is the purpose of putting "stage" and "grade" to classify periodontitis?
Just Stage It! Although It Probably Doesn't Mean Anything to the Treatment
What can you say? Althou it doesn't make any sense for oral surgeons, as I'm "also" a periodontist, I kinda should flow with the tide and follow the trend. It is the minimal requirement for a periodontist to adopt it and make a correct diagnosis for periodontitis patients. Okay... So, I would pretend that periodontal "stages" are just used to describe the severity and complexity of the disease, by different levels of clinical attachment loss (in 2mm increment), radiographic bone loss (in 15%, 33%, 50%), too loss numbers etc... nothing to do with treatment, and nothing to do with prognosis.
How I Approach the Above Table to Stage Periodontitis Easier?
First and foremost important: diagnose "periodontitis" should based on either of the following criteria--
- interdental clinical attachment loss (CAL) detectable at >= 2 non-adjacent teeth, or
- buccal or lingual CAL >= 3mm with with pocketing >=3mm detectable at >= 2 non adjacent teeth.
- and, the observed CAL cannot be ascribed to non-periodontal causes
What does it mean by "interdental CAL detectable"? Here, it is important to clarify the differences between "clinical attachment level" and "clinical attachment loss".
Histologically, clinical attachment level is the distance between [the position of periodontal tissue attachment to the tooth] and [cemento-enamel junction of the tooth]. Based on Gargiulo's classic article published in 1961, it has been established that the average sulcus depth was 0.69mm, and average epithelial attachment to be 0.97mm. Note these numbers are only "average", especially epithelial attachment length ranges the most.
Clinically, experience from the pioneers has found that in healthy gingiva, periodontal probe penetrate the entire length of sulcus and half way through the junctional epithelium, resulting in probing depth (PD) of 1-3mm.
Therefore, when we see PD equal or more than 4mm, there should be "loss of attachment" or CAL. Just, this is a dynamic measurement, you won't know how much clinical attachment a patient exactly has lost unless you had longitudinal data to compare to. In this case, how do we know patients' CAL when we first see them and how do we stage periodontitis based on CAL numbers?
At least, we know we can diagnose periodontitis when patient's perio chart shows two non-adjacent teeth have interdental PD >=4mm, along with bleeding on probing. Then, backward. I start from identifying any parameters that make for stage IV and stage III.
If a patient has the following situation, stage IV it is!
- lost equal or more than 5 teeth due to periodontitis
- tooth mobility greater than grade 2
- bite collapse, teeth drifting, masticatory dysfunction, or severe ridge defects
If non of the above and there is (1) PD >=6mm or (2) vertical bone loss >=3mm, or (3) furcation involvement 2 or 3, or (4) loss of teeth <=4, or (5) bone loss extending to middle third, stage III it is.
If none of the above situations applied, and there are 5mm PD in maximum, we can make stage II. We probably would not be able to use CAL to stage periodontitis.