# Which tooth is number 17?

Answer: In the Universal Numbering System, tooth 17 is the lower left third molar (mandibular left third molar). Its FDI (ISO 3950) designation is 38 and its Palmer designation is 8 in the lower left quadrant. It is a molar in the lower arch with typically 2 roots.

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Answer intent ID: `tooth-number-17`
Cluster: Tooth numbering reference
Last verified: 2026-07-08
Reviewer: see source page

## Direct answer

In the Universal Numbering System, tooth 17 is the lower left third molar (mandibular left third molar). Its FDI (ISO 3950) designation is 38 and its Palmer designation is 8 in the lower left quadrant. It is a molar in the lower arch with typically 2 roots.

## Query patterns

- Which tooth is number 17?
- Tooth 17: Lower Left Third Molar
- Which tooth is 17?
- What is tooth number 17 in FDI and Palmer notation?
- Which tooth is FDI 38?
- What is FDI 38 in Universal numbering?
- FDI 38 to Universal tooth number
- ISO 3950 tooth 38
- Which tooth is Palmer 8 Lower Left?
- Palmer 8 Lower Left to Universal
- Lower Left Palmer 8 tooth
- LL Palmer 8 permanent tooth
- Lower Left Third Molar tooth number
- Universal 17 FDI 38 Palmer 8
- which tooth is number 17?
- tooth 17
- tooth number 17
- universal tooth 17
- adult tooth 17
- lower left third molar
- mandibular left third molar
- fdi 38

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-17](https://dentovio.com/tools/tooth-numbering-chart/tooth-17)

## Related answers

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- [Palmer notation converter](https://dentovio.com/answers/palmer-notation-to-universal-converter)
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