permanent dentition · lower right quadrant
Tooth number 31
In the ADA Universal system, tooth 31 is the lower right second molar. It is written 47 in FDI notation and 7┐ in Palmer notation.
Notation
- Universal (ADA)
- 31
- FDI (ISO 3950)
- 47
- Palmer
- 7┐
- Tooth type
- molar
- Arch
- lower
- Side
- right
- Position from midline
- 7 of 8
Surfaces of tooth 31
As a posterior tooth it has an occlusal (chewing) table and a buccal (cheek) face. It has no incisal edge.
- 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.
- B Buccal — The cheek side. Used for premolars and molars.
- L Lingual — The tongue side. On upper teeth it is also called palatal.
- O Occlusal — The chewing surface. Premolars and molars only.
31 is ambiguous on its own
The number 31 is valid in both numbering systems and means a different tooth in each. In the Universal system it is the lower right second molar. In the FDI system it is the lower left central incisor — Universal 24.
If a chart does not state its system, a bare 31 does not identify a tooth. Look for numbers above 32 or letters A–T elsewhere on the chart: those only appear in one system and settle it.
How tooth 31 is written on a chart
Each of these is a valid entry for this tooth. Select one to open it in the decoder.
A combination such as MOD on tooth 31 names its mesial, occlusal and distal surfaces together — the pattern usually written MOD. See what MOD means and the full surface reference.
Where tooth 31 sits
- 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