In most dental offices, after the hygienist cleans your teeth, the dentist comes in to examine your teeth. Then, out of nowhere, he or she starts rattling off alpha-numeric jargon like, 3MOD, 5DO, 13MFD, and so on. The dentist is not looking at a bowl of alphabet soup, but, rather, using a form of dental shorthand. The numbers represent which teeth have cavities or other problems. Tooth number one is the upper right third molar or wisdom tooth, the farthest tooth back in the mouth. Tooth number sixteen is the upper left third molar. Tooth number seventeen is the lower left third molar, and tooth number thirty-two is the lower right third molar. So, teeth eight and nine are the upper front teeth, or left and right central incisors, and teeth twenty-four and twenty-five are the lower front teeth, or lower left and right central incisors.
The letter part of the code refers to different parts or surfaces of the tooth. An "M" mesial, or "D" distal, is the front or back surface of the tooth, respectively. An "O" occlusal, is the top or biting surface of a back tooth (molar or premolar), and "I" incisal, is the biting edge of front teeth (incisors and canines). A "B" buccal, is the surface of the tooth towards the cheek, and an "L" lingual, is the surface of the tooth towards the tongue. So if the dentist says number 3MOD, you'll know that you have a cavity on your upper right first molar, involving the front, top, and back parts of the tooth.