# Tooth 26: Lower Right Lateral Incisor

> In the Universal Numbering System, tooth 26 is the lower right lateral incisor (mandibular right lateral incisor). Its FDI (ISO 3950) designation is 42 and its Palmer designation is 2 in the lower right quadrant. It is a incisor in the lower arch with typically 1 root.

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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 26? In the Universal Numbering System, tooth 26 is the lower right lateral incisor (mandibular right lateral incisor). Its FDI (ISO 3950) designation is 42 and its Palmer designation is 2 in the lower right quadrant. It is a incisor in the lower arch with typically 1 root.
- Universal number: 26
- FDI / ISO 3950 designation: 42
- Palmer designation: 2 LR
- Plain-language name: Lower Right Lateral Incisor
- Anatomical name: Mandibular Right Lateral Incisor
- Quadrant: Lower Right
- Arch and side: lower, right
- Type: incisor
- Typical roots: 1

## Conversion table

| System | Designation |
| --- | --- |
| Universal Numbering System | 26 |
| FDI / ISO 3950 | 42 |
| Palmer notation | 2 LR |
| Tooth name | Lower Right Lateral Incisor |

## Search terms

- which tooth is number 26?
- tooth 26
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- universal tooth 26
- adult tooth 26
- lower right lateral incisor
- mandibular right lateral incisor
- fdi 42
- palmer 2
- lower right tooth 2
- lower right incisor

## 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 25: Lower Right Central Incisor](https://dentovio.com/tools/tooth-numbering-chart/tooth-25/index.html.md)
- [Next tooth: Tooth 27: Lower Right Canine](https://dentovio.com/tools/tooth-numbering-chart/tooth-27/index.html.md)