During your regular dental checkup, you may have heard us say things like
"15-MOD" or "3-buccal." It may sound like we're playing
some bingo-like game with your mouth, but actually, we're using a kind
of shorthand to quickly identify the surfaces of individual teeth. To help
you decode our conversations, we'd like to share some of our "secret"
Deciphering the names of teeth
Children start out with 20 teeth, which begin to erupt in babies as young as
6 months old. These primary teeth eventually are replaced with several kinds of
adult teeth, totaling 32 in all. Each kind performs specialized functions.
- Incisors: These 8 front teeth are good for biting because of their sharp
- Cuspids: Also called "canine teeth" or "eye teeth," these 4 pointed teeth
grasp and tear food.
- Bicuspids: Also called "premolars," these 8 teeth grind and mash food.
- Molars: These 12 large teeth, located in the most powerful part of the
mouth, also grind and mash food. Molars are particularly efficient at making
food soft enough to swallow.
Unlocking the numbers for teeth
Because there are several of each kind of tooth, using words to identify a
single tooth would be time-consuming and potentially confusing. For example,
having to refer to the "upper left lateral incisor" all the time would be a real
This is why we use a numbering system to quickly identify each individual
tooth. Instead of "upper left lateral incisor," we say "number 10." In the chart
at right, you can see how we number teeth in the United States. In other
countries, dentists often use different systems.
Decoding the outside surfaces of teeth
Each tooth has several surfaces, and we refer to each one separately when
talking about the condition of your teeth. For example, a cavity might occur in
just the biting surface or in the space where the sides of teeth meet. Similar
to the numbering system for teeth, we use letters to refer to each tooth
- "O" for occlusal: This refers to the top surface, which is colored red in
the illustration at right.
- "M" for mesial (MEE-zee-ull): The mesial surface of the tooth, indicated in
blue, is the side closest to the center of the mouth.
- "D" for distal: The distal surface, identified with yellow, is the side
closest to the back of the mouth.
- Buccal (BUCK-ull): This is the cheek side of a tooth.
- Lingual: This is the tongue side of lower teeth.
- Palatal (PAL-ah-tal): This is the palate side of upper teeth.
Solving the puzzle
Now let's combine the codes and solve the puzzle. For example, if you hear us
talk about decay in "15-MOD," what does that mean? The number 15 tooth is the
upper left 2nd molar. Decoding the letters, you know that MOD stands for mesial,
occlusal, and distal. This means that we've found decay on the biting surface of
the upper left 2nd molar and that the decay reaches from the front to the back
of the tooth. Let's hope this is just an example and not what we really find
when we examine your teeth!