Tooth 31 (FDI): mandibular left central incisor

The three numbers

Careful with plain numbers: Universal 31 is a different tooth, the mandibular right second molar (FDI 47).

About this tooth

Name

Mandibular left central incisor

Set

Adult (permanent)

Position

Lower arch, patient left (lower left, quadrant 3)

Erupts

6 to 7 years

Roots

1

Root canals

1

Crown surfaces

Mesial, distal, labial (facial), lingual and incisal.

Also written

#24 (Universal), 3.1 (FDI with a dot), lower left 1

Read on 23 October 2026. Sources: American Dental Association, Tooth development charts (primary and permanent); Number of roots and canals, from Ingle's Endodontics; Dental anatomy, citing Ash and Nelson, Wheeler's Dental Anatomy, Physiology and Occlusion. Ages and counts are usual figures, and teeth vary from person to person.

On the chart

Teeth next to it

• Toward the middle: 41 (mandibular right central incisor)
• Toward the back: 32 (mandibular left lateral incisor)
• Across the midline: 41 (mandibular right central incisor)
• In the other arch: 21 (maxillary left central incisor)

Convert any other tooth with the full chart.