# Which tooth is number 24?

Answer: In the Universal Numbering System, tooth 24 is the lower left central incisor (mandibular left central incisor). Its FDI (ISO 3950) designation is 31 and its Palmer designation is 1 in the lower left quadrant. It is a incisor in the lower arch with typically 1 root.

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Answer intent ID: `tooth-number-24`
Cluster: Tooth numbering reference
Last verified: 2026-07-08
Reviewer: see source page

## Direct answer

In the Universal Numbering System, tooth 24 is the lower left central incisor (mandibular left central incisor). Its FDI (ISO 3950) designation is 31 and its Palmer designation is 1 in the lower left quadrant. It is a incisor in the lower arch with typically 1 root.

## Query patterns

- Which tooth is number 24?
- Tooth 24: Lower Left Central Incisor
- Which tooth is 24?
- What is tooth number 24 in FDI and Palmer notation?
- Which tooth is FDI 31?
- What is FDI 31 in Universal numbering?
- FDI 31 to Universal tooth number
- ISO 3950 tooth 31
- Which tooth is Palmer 1 Lower Left?
- Palmer 1 Lower Left to Universal
- Lower Left Palmer 1 tooth
- LL Palmer 1 permanent tooth
- Lower Left Central Incisor tooth number
- Universal 24 FDI 31 Palmer 1
- which tooth is number 24?
- tooth 24
- tooth number 24
- universal tooth 24
- adult tooth 24
- lower left central incisor
- mandibular left central incisor
- fdi 31

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-24](https://dentovio.com/tools/tooth-numbering-chart/tooth-24)

## Related answers

- [FDI to Universal tooth number converter](https://dentovio.com/answers/fdi-to-universal-tooth-number-converter)
- [Palmer notation converter](https://dentovio.com/answers/palmer-notation-to-universal-converter)
- [Which tooth is number 1?](https://dentovio.com/answers/tooth-number-1)
- [Which tooth is number 2?](https://dentovio.com/answers/tooth-number-2)