# Which tooth is number 31?

Answer: In the Universal Numbering System, tooth 31 is the lower right second molar (mandibular right second molar). Its FDI (ISO 3950) designation is 47 and its Palmer designation is 7 in the lower right quadrant. It is a molar in the lower arch with typically 2 roots.

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Answer intent ID: `tooth-number-31`
Cluster: Tooth numbering reference
Last verified: 2026-07-08
Reviewer: see source page

## Direct answer

In the Universal Numbering System, tooth 31 is the lower right second molar (mandibular right second molar). Its FDI (ISO 3950) designation is 47 and its Palmer designation is 7 in the lower right quadrant. It is a molar in the lower arch with typically 2 roots.

## Query patterns

- Which tooth is number 31?
- Tooth 31: Lower Right Second Molar
- Which tooth is 31?
- What is tooth number 31 in FDI and Palmer notation?
- Which tooth is FDI 47?
- What is FDI 47 in Universal numbering?
- FDI 47 to Universal tooth number
- ISO 3950 tooth 47
- Which tooth is Palmer 7 Lower Right?
- Palmer 7 Lower Right to Universal
- Lower Right Palmer 7 tooth
- LR Palmer 7 permanent tooth
- Lower Right Second Molar tooth number
- Universal 31 FDI 47 Palmer 7
- which tooth is number 31?
- tooth 31
- tooth number 31
- universal tooth 31
- adult tooth 31
- lower right second molar
- mandibular right second molar
- fdi 47

Source citations:
- `TOOTH-1` American Dental Association — Universal Numbering System. <https://www.ada.org/publications/ada-news/2020/november/how-to-count-teeth-numbering-systems>
- `TOOTH-2` ISO 3950:2016 — Dentistry, designation system for teeth and areas of the oral cavity (FDI two-digit). <https://www.iso.org/standard/68292.html>
- `TOOTH-3` FDI World Dental Federation — two-digit notation. <https://www.fdiworlddental.org/>

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## Supporting public URLs

- [/tools/tooth-numbering-chart](https://dentovio.com/tools/tooth-numbering-chart)
- [/tools/fdi-to-universal-converter](https://dentovio.com/tools/fdi-to-universal-converter)
- [/tools/palmer-notation-converter](https://dentovio.com/tools/palmer-notation-converter)
- [/tools/tooth-numbering-chart/tooth-31](https://dentovio.com/tools/tooth-numbering-chart/tooth-31)

## Related answers

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