# Which tooth is number 26?

Answer: 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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Answer intent ID: `tooth-number-26`
Cluster: Tooth numbering reference
Last verified: 2026-07-08
Reviewer: see source page

## Direct answer

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.

## Query patterns

- Which tooth is number 26?
- Tooth 26: Lower Right Lateral Incisor
- Which tooth is 26?
- What is tooth number 26 in FDI and Palmer notation?
- Which tooth is FDI 42?
- What is FDI 42 in Universal numbering?
- FDI 42 to Universal tooth number
- ISO 3950 tooth 42
- Which tooth is Palmer 2 Lower Right?
- Palmer 2 Lower Right to Universal
- Lower Right Palmer 2 tooth
- LR Palmer 2 permanent tooth
- Lower Right Lateral Incisor tooth number
- Universal 26 FDI 42 Palmer 2
- which tooth is number 26?
- tooth 26
- tooth number 26
- universal tooth 26
- adult tooth 26
- lower right lateral incisor
- mandibular right lateral incisor
- fdi 42

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-26](https://dentovio.com/tools/tooth-numbering-chart/tooth-26)

## Related answers

- [FDI to Universal tooth number converter](https://dentovio.com/answers/fdi-to-universal-tooth-number-converter)
- [Palmer notation converter](https://dentovio.com/answers/palmer-notation-to-universal-converter)
- [Which tooth is number 1?](https://dentovio.com/answers/tooth-number-1)
- [Which tooth is number 2?](https://dentovio.com/answers/tooth-number-2)