What do dental terms that use numbers and letters mean?

After a dental hygienist cleans your teeth, the dentist will come in to examine them. Out of nowhere, he or she rattles off alpha-numeric jargon: "3MOD," "5DO," "13MFD" and so on. The dentist is using a form of dental shorthand.

Numbers represent teeth that have cavities or other problems. The upper right, third molar or wisdom tooth (this is the one farthest back in the mouth) is tooth number one. Tooth 16 is the upper left, third molar. Number 17 is the lower left, third molar. And 32 is the lower right, third molar. Therefore, teeth eight and nine are the upper front teeth (called the left and right central incisors). Teeth 24 and 25 are the lower front teeth (called the lower left and right central incisors).

The code letter refers to different parts or surfaces of the tooth. For example, "M" stands for mesial (the front surface of the tooth). "D" stands for distal (the back surface). An "O," which stands for occlusal, is the top surface of a back tooth. "I," which stands for incisal, is the biting edge of incisors and canines (the front teeth). "B," which stands for buccal, is the surface of the tooth that faces the cheek. "L," which stands for lingual, is the surface towards the tongue.

Now, if the dentist says number 3MOD, you know you have a cavity on your upper right first molar and that it involves the front, top, and back parts of the tooth.
When dentists and dental hygienists talk about numbers and letters as they peer into your mouth, they are identifying specific teeth. Using a coding system of letters and numbers allows dentists to specify which teeth have decay or other problems. There are several systems used in dentistry to identify specific teeth. In one system, the tooth farthest back on the right side of your mouth in the upper jaw is considered number one. The next tooth is number two and so on until reaching the last upper tooth. Numbering continues with the rear-most tooth on the lower left side. When your dentist attaches a letter to a number, he or she is referring to the side or surface area of a tooth. "M" stands for mesial, which is a medical term for the front of a tooth. "D" stands for distal, or the rear side of a tooth. Other letters are used to describe different tooth surfaces.

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