# Tooth 17: Lower Left Third Molar

> 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.

URL: https://dentovio.com/tools/tooth-numbering-chart/tooth-17

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Last verified: 2026-07-08

Neutral tooth-designation reference only; not clinical, diagnostic, or treatment advice. Root counts describe typical permanent-tooth morphology and vary between individuals.

## Direct answer

- Which tooth is number 17? 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.
- Universal number: 17
- FDI / ISO 3950 designation: 38
- Palmer designation: 8 LL
- Plain-language name: Lower Left Third Molar
- Anatomical name: Mandibular Left Third Molar
- Quadrant: Lower Left
- Arch and side: lower, left
- Type: molar
- Typical roots: 2

## Conversion table

| System | Designation |
| --- | --- |
| Universal Numbering System | 17 |
| FDI / ISO 3950 | 38 |
| Palmer notation | 8 LL |
| Tooth name | Lower Left Third Molar |

## Note

Commonly called the wisdom tooth.

## Search terms

- which tooth is number 17?
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- fdi 38
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- lower left molar

## Sources

- `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/>

## Related

- [Full tooth numbering chart](https://dentovio.com/tools/tooth-numbering-chart/index.html.md)
- [FDI to Universal converter](https://dentovio.com/tools/fdi-to-universal-converter/index.html.md)
- [Palmer notation converter](https://dentovio.com/tools/palmer-notation-converter/index.html.md)
- [Previous tooth: Tooth 16: Upper Left Third Molar](https://dentovio.com/tools/tooth-numbering-chart/tooth-16/index.html.md)
- [Next tooth: Tooth 18: Lower Left Second Molar](https://dentovio.com/tools/tooth-numbering-chart/tooth-18/index.html.md)