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Which tooth is number 9?

In the Universal Numbering System, tooth 9 is the upper left central incisor (maxillary left central incisor). Its FDI (ISO 3950) designation is 21 and its Palmer designation is 1 in the upper left quadrant. It is a incisor in the upper arch with typically 1 root.

Last verified
2026-07-08
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Query patterns

  • Which tooth is number 9?
  • Tooth 9: Upper Left Central Incisor
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  • What is tooth number 9 in FDI and Palmer notation?
  • Which tooth is FDI 21?
  • What is FDI 21 in Universal numbering?
  • FDI 21 to Universal tooth number
  • ISO 3950 tooth 21
  • Which tooth is Palmer 1 Upper Left?
  • Palmer 1 Upper Left to Universal
  • Upper Left Palmer 1 tooth
  • UL Palmer 1 permanent tooth
  • Upper Left Central Incisor tooth number
  • Universal 9 FDI 21 Palmer 1
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  • upper left central incisor
  • maxillary left central incisor
  • fdi 21

Source citations

  • TOOTH-1 American Dental Association — Universal Numbering System (ada.org)
  • TOOTH-2 ISO 3950:2016 — Dentistry, designation system for teeth and areas of the oral cavity (FDI two-digit) (iso.org)
  • TOOTH-3 FDI World Dental Federation — two-digit notation (fdiworlddental.org)

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