# Which tooth is number 12?

Answer: In the Universal Numbering System, tooth 12 is the upper left first premolar (maxillary left first premolar). Its FDI (ISO 3950) designation is 24 and its Palmer designation is 4 in the upper left quadrant. It is a premolar in the upper arch with typically 2 roots.

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Answer intent ID: `tooth-number-12`
Cluster: Tooth numbering reference
Last verified: 2026-07-08
Reviewer: see source page

## Direct answer

In the Universal Numbering System, tooth 12 is the upper left first premolar (maxillary left first premolar). Its FDI (ISO 3950) designation is 24 and its Palmer designation is 4 in the upper left quadrant. It is a premolar in the upper arch with typically 2 roots.

## Query patterns

- Which tooth is number 12?
- Tooth 12: Upper Left First Premolar
- Which tooth is 12?
- What is tooth number 12 in FDI and Palmer notation?
- Which tooth is FDI 24?
- What is FDI 24 in Universal numbering?
- FDI 24 to Universal tooth number
- ISO 3950 tooth 24
- Which tooth is Palmer 4 Upper Left?
- Palmer 4 Upper Left to Universal
- Upper Left Palmer 4 tooth
- UL Palmer 4 permanent tooth
- Upper Left First Premolar tooth number
- Universal 12 FDI 24 Palmer 4
- which tooth is number 12?
- tooth 12
- tooth number 12
- universal tooth 12
- adult tooth 12
- upper left first premolar
- maxillary left first premolar
- fdi 24

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-12](https://dentovio.com/tools/tooth-numbering-chart/tooth-12)

## 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)