Understanding Dental Teeth Numbering Chart

woman pointing at her teeth

Sitting in a dentist’s chair is never a very relaxing experience, and a lot of people find it isn’t helped by the dentist and their staff talking about your teeth in a secret code. Well, it isn’t really a secret code, and they are not doing it to hide vital information from you. 

Like most professions, dentistry has its own lingo that outsiders can have great difficulty in trying to follow. They use teeth numbers and other terms and references that are perfectly understandable to them but might as well be Greek to the poor patient sitting in the chair. In this article, we’ll help you crack the code that is dentist speak.

What are quadrants?

When you hear your dentist muttering to their staff about quadrants, they’re not doing complicated mathematical equations to calculate how much to charge you. They are actually referring to parts of your mouth.

For ease of reference, dentists divide the mouth into four parts or quadrants. The upper part of your mouth is made up of the first two quadrants, while the third and fourth are in the lower half.

Tooth numbering system

In order to keep track of the condition of each tooth, dentists use a dental tooth numbering chart. This varies from country to country — the UK uses the Palmer Notation Method while in Canada they use something called the ISO/FDI system. Here in the good old US of A, we use the (not very aptly maned) Universal System. Understanding this chart will help you find out a lot about the state of your overall oral hygiene.

The Universal teeth number chart was first proposed by a German dentist, Julius Parreidt, way back in 1882. In this teeth numbering system, teeth numbers for primary and permanent teeth are assigned differently. The system was approved and accepted by the ADA (American Dental Association) and, as we said, is the most commonly used by dentists in the US.

The advantage of this system, and the main reason why it was accepted by the ADA, is that it numbers teeth sequentially, and this makes it quick and easy to locate the desired tooth in the mouth. It does have one major disadvantage though, which is why it is not accepted universally, despite the name (a bit like the World Series in baseball, isn’t it) and that is that it does not allow for the numbering of supernumerary teeth (these are extra teeth that can sometimes grow in a person’s mouth).

Primary teeth numbering under the Universal Numbering System

This is a bit misleading as primary teeth aren’t given numbers under the Universal System, they are assigned letters. This is done so that technicians and others will immediately know whether the teeth in question are primary or permanent merely from looking at the records.

Numbering (lettering) begins in the upper part of the mouth. The right second molar (the big teeth at the back of your mouth) in the upper right quadrant is assigned the letter A, the next B, etc. all the way round to the second molar in the upper left quadrant which becomes J. The lettering continues sequentially in the bottom half of the mouth, starting with K, the lower second left molar, right under J, continuing the clockwise sequence of the quadrants, and goes all the way to T, the second molar in the bottom right hand quadrant.

Permanent teeth numbering under the Universal Numbering System

This follows the same pattern as with primary teeth except this time, the tooth number chart uses actual numbers, from 1 to 32. The same as primary teeth, the numbering starts with the third upper right molar which is designated 1 and continues in sequential order to the upper left third molar, which is 16. The bottom half of your mouth begins at 17, the bottom left third molar and the numbering continues its way around to number 32, the bottom right third molar.

Gum Numbering

Now that you understand the teeth numbering chart, you might start to feel a little bit more relaxed in the dentist’s chair. But then you’ll hear other numbers which aren’t on the chart being bandied about and end up feeling just as confused as before. This is because most people forget that dentists don’t just take care of the overall health of your teeth, they also look after the health of your gums. And as gum disease like gingivitis or periodontis are among the most common complaints that dentists have to deal with, they have a code to describe that, too.

To check the health of your gums, dentists measure the gap between the tooth and the gum pocket and will give each of your teeth a number for its gum gap.

As gum disease causes the gums to recede and pull back from the teeth, you as the patient want these numbers to be small — the smaller the better. Any measurement of three millimeters or less is good. It means your diligent use of your toothbrush and dental floss has paid off and your gums are healthy. Anything larger than 3mm is indicative of problems such as plaque and tartar build-up, and the higher the number is, the worse the problem is.

If the measurement is between three and five millimeters, it means you’re not keeping your teeth as clean as you should. Inflammation occurs easily and frequently in these circumstances, and you could even be looking at the start of periodontal disease or even bone loss. 

If the number is higher than 5mm, then gum disease could have set already and will need to be dealt with, unless the gap is caused by chipping or other damage. The first step is a deep cleaning or dental scaling to remove any buildup from the teeth and give a clearer picture of the damage that has already been done. Once this is assessed, the dentist will decide how to proceed. In extreme cases, surgery may be necessary, although a good dentist will explore all other options before resorting to the knife.

We hope that this article has helped to clarify the meaning of the cryptic references that are constantly being exchanged between dentists and their staff. Remember, these terms are not being used to hide things from you but merely as quick and easy terms of reference. 

So, the next time you are in the chair and wondering what on earth your dentist is talking about, try asking. Provided of course that there are no tube, sharp instruments, or fingers in your mouth at the time. 

Here at Doral Sedation Dentistry, we are always happy to keep our patients up-to-date on their dental health. Book an appointment with us, today

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