Teeth chart: find any tooth by its FDI number

A teeth chart divides the mouth into four quadrants: upper right, upper left, lower left and lower right. Right and left are always named from the patient's point of view, not from the dentist facing you, so a chart can look back to front at first. Within each quadrant, teeth are counted from the middle of the mouth towards the back. Healthdirect describes four types of adult teeth: incisors at the front, canines, premolars at the side and molars at the back, including the wisdom teeth.

In each adult quadrant the order is the same. Position 1 is the central incisor, 2 the lateral incisor and 3 the canine. Positions 4 and 5 are the first and second premolars. Positions 6, 7 and 8 are the first, second and third molars, and the third molar is the wisdom tooth. The Australian Dental Association notes that baby teeth have no premolars: children have incisors, canines and molars. Adults have 32 teeth in a full set and children have 20 baby teeth.

• 1 = central incisor
• 2 = lateral incisor
• 3 = canine
• 4 = first premolar, 5 = second premolar
• 6 = first molar, 7 = second molar
• 8 = third molar (wisdom tooth)

Australian dentists generally number teeth with the FDI system, named after the FDI World Dental Federation. NSW Health's Emergency Care Institute, for example, asks clinicians to describe a tooth using the FDI system. Every tooth has two digits. The first digit is the quadrant and the second is the position, counted from the midline towards the back. Adult quadrants are 1 (upper right), 2 (upper left), 3 (lower left) and 4 (lower right). So 16 is the upper right first molar and 36 is the lower left first molar.

Baby teeth use quadrants 5 to 8 in the same order: 5 is upper right, 6 upper left, 7 lower left and 8 lower right. Each baby quadrant has five teeth, so 55 is the upper right second baby molar and 71 is the lower left baby central incisor. Read the number as two separate digits: 36 is "three six", not thirty-six. The chart on this page uses FDI numbers on every tooth.

The Universal system is used mainly in the United States. The American Dental Association describes it as assigning a unique number from 1 to 32 to adult teeth and a letter from A to T to baby teeth. It starts with the upper right third molar as 1, runs across the upper jaw to 16, then continues along the lower jaw from the lower left third molar, 17, to the lower right third molar, 32. So FDI 16 is Universal 3, while Universal 16 is the upper left wisdom tooth.

Tooth numbers appear on treatment plans, X-ray reports, referral letters and invoices. If you compare an Australian quote with one from abroad, the two plans may use different systems. Use the chart to translate both into the same teeth, then check that both plans really cover the same teeth and the same work. The chart only explains numbering. It does not tell you whether a tooth needs treatment, so ask your dentist if anything on your plan is unclear.