# Tooth 19: Lower Left First Molar

> In the Universal Numbering System, tooth 19 is the lower left first molar (mandibular left first molar). Its FDI (ISO 3950) designation is 36 and its Palmer designation is 6 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-19

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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 19? In the Universal Numbering System, tooth 19 is the lower left first molar (mandibular left first molar). Its FDI (ISO 3950) designation is 36 and its Palmer designation is 6 in the lower left quadrant. It is a molar in the lower arch with typically 2 roots.
- Universal number: 19
- FDI / ISO 3950 designation: 36
- Palmer designation: 6 LL
- Plain-language name: Lower Left First Molar
- Anatomical name: Mandibular Left First Molar
- Quadrant: Lower Left
- Arch and side: lower, left
- Type: molar
- Typical roots: 2

## Conversion table

| System | Designation |
| --- | --- |
| Universal Numbering System | 19 |
| FDI / ISO 3950 | 36 |
| Palmer notation | 6 LL |
| Tooth name | Lower Left First Molar |

## Search terms

- which tooth is number 19?
- tooth 19
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- universal tooth 19
- adult tooth 19
- lower left first molar
- mandibular left first molar
- fdi 36
- palmer 6
- lower left tooth 6
- 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 18: Lower Left Second Molar](https://dentovio.com/tools/tooth-numbering-chart/tooth-18/index.html.md)
- [Next tooth: Tooth 20: Lower Left Second Premolar](https://dentovio.com/tools/tooth-numbering-chart/tooth-20/index.html.md)