Dental charting notation
What does #19 MOD mean?
A charting entry packs two separate standards into one string: a tooth number and a set of surface codes. This decodes both at once, shows the tooth, and marks the surfaces it refers to.
Decode a charting expression
Type what is written on the chart — a tooth number, a surface code, or both. #19 MOD resolves to a specific tooth with its mesial, occlusal and distal surfaces marked.
Universal numbers 1–32 and A–T, or FDI numbers 11–48 and 51–85. Surface codes M, D, O, I, B, F and L.
The short answer
#19 is tooth 19 in the ADA Universal system — the lower left first molar, written 36 in FDI notation. MOD names three of its surfaces: Mesial, Occlusal and Distal. Together the entry describes work involving the front, chewing and back surfaces of that one molar.
Tooth number chart
All 32 permanent teeth. The large number is the ADA Universal number used across the United States; the small number below it is the FDI number used in most of the rest of the world. Select any tooth for its full notation and surfaces.
- 1 18 upper right third molar
- 2 17 upper right second molar
- 3 16 upper right first molar
- 4 15 upper right second premolar
- 5 14 upper right first premolar
- 6 13 upper right canine
- 7 12 upper right lateral incisor
- 8 11 upper right central incisor
- 9 21 upper left central incisor
- 10 22 upper left lateral incisor
- 11 23 upper left canine
- 12 24 upper left first premolar
- 13 25 upper left second premolar
- 14 26 upper left first molar
- 15 27 upper left second molar
- 16 28 upper left third molar
- 32 48 lower right third molar
- 31 47 lower right second molar
- 30 46 lower right first molar
- 29 45 lower right second premolar
- 28 44 lower right first premolar
- 27 43 lower right canine
- 26 42 lower right lateral incisor
- 25 41 lower right central incisor
- 24 31 lower left central incisor
- 23 32 lower left lateral incisor
- 22 33 lower left canine
- 21 34 lower left first premolar
- 20 35 lower left second premolar
- 19 36 lower left first molar
- 18 37 lower left second molar
- 17 38 lower left third molar
Primary teeth use letters A to T in the Universal system and numbers 51 to 85 in FDI. The decoder handles both — try #A MO.
The seven surface codes
| Code | Surface | What it means |
|---|---|---|
| M | Mesial | The side facing the front of the mouth, toward the midline. |
| D | Distal | The side facing the back of the mouth, away from the midline. |
| O | Occlusal | The chewing surface. Premolars and molars only. |
| I | Incisal | The biting edge. Incisors and canines only. |
| B | Buccal | The cheek side. Used for premolars and molars. |
| F | Facial | The lip or cheek side. On front teeth this is also called labial. |
| L | Lingual | The tongue side. On upper teeth it is also called palatal. |
Definitions follow the standard surface code list published by the US Centers for Medicare & Medicaid Services. Full detail on Tooth surfaces.
When a number means two different teeth
The Universal system numbers teeth 1–32. FDI uses two digits where the first is the quadrant and the second is the position from the midline, giving 11–18, 21–28, 31–38 and 41–48. Where those ranges overlap, the same bare number is valid in both systems and points at a different tooth in each.
Universal 14 is the upper left first molar. FDI 14 is the upper right first premolar. Different arch side, different tooth type. The decoder shows both readings rather than guessing which chart you are holding.
The 18 ambiguous numbers
- 11
- 12
- 13
- 14
- 15
- 16
- 17
- 18
- 21
- 22
- 23
- 24
- 25
- 26
- 27
- 28
- 31
- 32
Everything else is unambiguous: 1–10, 19, 20, 29 and 30 exist only in Universal; 33–38 and 41–48 exist only in FDI.
Common questions
- What does #19 MOD mean?
- Tooth 19 in the ADA Universal system — the lower left first molar — with three surfaces involved: Mesial, Occlusal and Distal. The number identifies the tooth and the letters identify which of its surfaces are being described.
- Does the number 14 always mean the same tooth?
- No. In the Universal system 14 is the upper left first molar. In the FDI system 14 is the upper right first premolar. Eighteen numbers are valid in both systems and mean different teeth in each, so a bare number is only unambiguous once you know which system the chart uses.
- What are the tooth surface codes?
- M mesial, D distal, O occlusal, I incisal, B buccal, F facial and L lingual. Occlusal applies to premolars and molars; incisal applies to incisors and canines.
- How many teeth are in the Universal numbering system?
- Thirty-two permanent teeth, numbered 1 to 32 starting at the upper right third molar and finishing at the lower right third molar. Primary teeth use the letters A to T.