Calculus is a Poor Predictor

Calculus is a Poor Predictor

If you are a veterinarian in small animal practice, how are you assessing the oral health of your patients during their annual wellness examination? Chances are, you ‘flip the lip’ and have a look in the mouth to see what you can see.

One of the common criteria to be assessed is how much calculus/tartar is visible on the crowns of the teeth. While that is certainly something to be noted, you also need to keep in mind that the amount of calculus on the crowns of the teeth is actually a very poor predictor of periodontal health. In fact, there is almost no relationship between the amount of calculus on the crowns of the teeth and periodontal status. That is because periodontal disease is what is going on below the gum line, not on the crowns.

For more on the hidden nature of periodontal disease, their is this paper – Periodontal Disease is Hidden. I also have a video on this post that describes periodontal anatomy and the progression of disease – Periodontal Anatomy Video

Here are some examples to illustrate what I am getting at. They are by no means rare findings. I see this sort of thing all the time.

First we have a case with lots of coronal calculus but no significant periodontal disease.

Lots of coronal calculus in this mature Chihuahua, so you could be forgiven for assuming there is lots of periodontal disease, however…
Radiographically, there is no bone loss and…
After cleaning things up, they were in quite good shape – no extractions needed.
And much the same situation around his mandibular canines. Lots of coronal calculus…
Radiographs show no bone loss
And there was just mild, reversible gingivitis.

One the other hand…

In this clinical photograph, there is virtually no plaque, calculus or gingivitis. Things look really healthy… above the surface. However…
Radiographically, we can see end-stage periodontal disease with bone loss completely encompassing the distal root of the molar. This, in turn, resulted in bacteria getting into the tooth through the root tip to cause septic pulp necrosis and then infection oozed out through the mesial root tip causing bone loss there too.
There is significant calculus at the mesial aspect of the first molar and distal aspect of the fourth premolar and no calculus at the distal aspect of the first molar or on the crown on the second molar. So, based on this photograph where do you think the periodontal disease is hiding?
Well, there you go. The periodontal defect is below the area with no calculus and there is no periodontal disease below the area where there is calculus.

What are the take-aways from this? There are a few that come to mind.

  1. If you are relying on the amount of coronal calculus visible on conscious examination to determine when a pet is in need of a detailed dental assessment and treatment, you will be missing a lot of cases in need of care. Not only is periodontal disease a hidden problem, the amount of calculus on the crowns has no predictive value for endodontic disease, tooth resorption, cyst formation or a number of other dental/oral pathologies.
  2. There are lots of products in the market that claim to help control ‘tartar’ (the lay-term for calculus) but since calculus on the crowns of the teeth is not really the problem, how much value would these products have, even if they did what they claim (and most have no research to back their claims, so…)? To look for products that have at least some research to warrant their use, visit and favour products with a claim from plaque control over ones that just have a claim for tartar control.
  3. Anesthesia-Free Dentistry, which targets coronal calculus, is going to be worse than useless. It is like putting a fresh coat of paint on rotting window frames. It might look better on the surface but the rot is continuing out of view. For more on AFD, have a look at my page devoted to that subject.

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