# Tooth 15: Upper Left Second Molar

> In the Universal Numbering System, tooth 15 is the upper left second molar (maxillary left second molar). Its FDI (ISO 3950) designation is 27 and its Palmer designation is 7 in the upper left quadrant. It is a molar in the upper arch with typically 3 roots.

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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 15? In the Universal Numbering System, tooth 15 is the upper left second molar (maxillary left second molar). Its FDI (ISO 3950) designation is 27 and its Palmer designation is 7 in the upper left quadrant. It is a molar in the upper arch with typically 3 roots.
- Universal number: 15
- FDI / ISO 3950 designation: 27
- Palmer designation: 7 UL
- Plain-language name: Upper Left Second Molar
- Anatomical name: Maxillary Left Second Molar
- Quadrant: Upper Left
- Arch and side: upper, left
- Type: molar
- Typical roots: 3

## Conversion table

| System | Designation |
| --- | --- |
| Universal Numbering System | 15 |
| FDI / ISO 3950 | 27 |
| Palmer notation | 7 UL |
| Tooth name | Upper Left Second Molar |

## Search terms

- which tooth is number 15?
- tooth 15
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- upper left second molar
- maxillary left second molar
- fdi 27
- palmer 7
- upper left tooth 7
- upper 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 14: Upper Left First Molar](https://dentovio.com/tools/tooth-numbering-chart/tooth-14/index.html.md)
- [Next tooth: Tooth 16: Upper Left Third Molar](https://dentovio.com/tools/tooth-numbering-chart/tooth-16/index.html.md)