# Which tooth is number 1?

Answer: In the Universal Numbering System, tooth 1 is the upper right third molar (maxillary right third molar). Its FDI (ISO 3950) designation is 18 and its Palmer designation is 8 in the upper right quadrant. It is a molar in the upper arch with typically 3 roots.

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Answer intent ID: `tooth-number-1`
Cluster: Tooth numbering reference
Last verified: 2026-07-08
Reviewer: see source page

## Direct answer

In the Universal Numbering System, tooth 1 is the upper right third molar (maxillary right third molar). Its FDI (ISO 3950) designation is 18 and its Palmer designation is 8 in the upper right quadrant. It is a molar in the upper arch with typically 3 roots.

## Query patterns

- Which tooth is number 1?
- Tooth 1: Upper Right Third Molar
- Which tooth is 1?
- What is tooth number 1 in FDI and Palmer notation?
- Which tooth is FDI 18?
- What is FDI 18 in Universal numbering?
- FDI 18 to Universal tooth number
- ISO 3950 tooth 18
- Which tooth is Palmer 8 Upper Right?
- Palmer 8 Upper Right to Universal
- Upper Right Palmer 8 tooth
- UR Palmer 8 permanent tooth
- Upper Right Third Molar tooth number
- Universal 1 FDI 18 Palmer 8
- which tooth is number 1?
- tooth 1
- tooth number 1
- universal tooth 1
- adult tooth 1
- upper right third molar
- maxillary right third molar
- fdi 18

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-1](https://dentovio.com/tools/tooth-numbering-chart/tooth-1)

## 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 2?](https://dentovio.com/answers/tooth-number-2)
- [Which tooth is number 3?](https://dentovio.com/answers/tooth-number-3)