# Tooth #9 (FDI 21): upper left central incisor

> FDI tooth 21 is the upper left central incisor (quadrant 2): Universal #9, Palmer UL1. With neighbouring teeth and the full chart.

Source: https://hajto.de/en/tooth-chart/tooth-21  
Last updated: 2026-10-17T11:14:40Z  
German version: https://hajto.de/zahnschema/zahn-21.md

- **FDI (ISO 3950):** 21
- **Universal (ADA):** #9
- **Palmer:** └1 (UL1)
- **Name:** Upper left central incisor
- **Tooth type:** Central incisor
- **Group:** Anterior tooth
- **Quadrant:** Quadrant 2: upper left (maxillary left)
- **Dentition:** Permanent dentition

## Neighbouring teeth

- [Tooth 11](https://hajto.de/en/tooth-chart/tooth-11.md): upper right central incisor
- [Tooth 22](https://hajto.de/en/tooth-chart/tooth-22.md): upper left lateral incisor

## Opposing tooth (same position in the opposite jaw)

- [Tooth 31](https://hajto.de/en/tooth-chart/tooth-31.md): lower left central incisor

[Interactive tooth chart](https://hajto.de/en/tooth-chart) · Reference for dentists and dental students. Notation according to the FDI two-digit system (ISO 3950) and the ADA Universal Numbering System.