Maxillary canine: FDI 13 and 23

The numbers on both sides

In FDI the first digit is the quadrant and the second is the position counted from the midline. 13 is quadrant 1, position 3: the upper right canine. 23 is the same position in quadrant 2, on the upper left. Universal numbers adult teeth from 1 at the upper right third molar around to 32 at the lower right third molar, which makes this tooth 6 on the upper right and 11 on the upper left. Palmer writes the position inside a bracket that shows the quadrant. In plain text that gives UR3 and UL3.

A plain number can name two different teeth, so the system matters. Universal 13 is the maxillary left second premolar, which is FDI 25. Universal 23 is the mandibular left lateral incisor, which is FDI 32.

Crown surfaces: mesial, distal, labial (facial), lingual and incisal.

The ADA chart also uses the older name cuspid.

Development and eruption

Calcification starts at 4 to 5 months and the crown is done by 6 to 7 years. The tooth erupts at 11 to 12 years, later than any other maxillary front tooth, and the root is not finished until 13 to 15 years, the latest root completion of any front tooth.

Read on 24 October 2026. Sources: Human tooth development, tables citing Ash and Nelson, Wheeler's Dental Anatomy, Physiology and Occlusion (Wikipedia); American Dental Association, Tooth development charts (primary and permanent). Figures are usual values, and teeth vary from person to person.

Crown

The crown has one pointed cusp. The mesial slope of the cusp is shorter than the distal slope, a fact used to orient an extracted tooth. A ridge from the middle labial lobe runs down the front, and on the back a large cingulum can look like a small cusp, with marginal ridges that run into it.

The crown is about as long as a central incisor, and its labial width is about 1 mm less. The mesial contact sits near the junction of the incisal and middle thirds, while the distal contact is lower, in the middle third.

Read on 24 October 2026. Sources: Craciunescu and others, Dental Anatomy and Morphology of Permanent Teeth, in Human Teeth, From Function to Esthetics (IntechOpen, 2023); MolarPath note Permanent tooth morphology (built on Wheeler's Dental Anatomy, 11th ed., and Sturdevant's Operative Dentistry, 8th ed.). Figures are usual values, and teeth vary from person to person.

Roots and canals

The root is single and is the longest of any tooth. Ingle's Endodontics tabulates one root and one canal. A review of Saudi CBCT studies reports Vertucci type I, a single canal from orifice to apex, in 98.3 percent of maxillary canines, and an Indian CBCT sample of 250 canines found 81.6 percent type I and 11.6 percent type III. The figures differ by population.

The long root resists the sideways loads of canine guidance when the jaw moves from side to side.

Read on 24 October 2026. Sources: Number of roots and canals, from Ingle's Endodontics (animated-teeth.com); Asiri and others, Root Morphology and Canal Configuration of Permanent Canines Among Saudi Population, Int J Gen Med 2022; Amardeep and others, Root Canal Morphology of Permanent Maxillary and Mandibular Canines in Indian Population Using CBCT, Anatomy Research International 2014; MolarPath note Permanent tooth morphology (built on Wheeler's Dental Anatomy, 11th ed., and Sturdevant's Operative Dentistry, 8th ed.). Figures are usual values, and teeth vary from person to person.

Neighbors and the baby tooth before it

Compared with the lateral incisor, the canine has a longer root and a single cusp in place of an incisal edge. Compared with the mandibular canine, the crown is wider and slightly shorter, with a stronger cingulum and stronger lingual ridges.

The canine replaces the primary canine, which a Columbia primary anatomy lecture describes as long and sharp. In the maxilla the premolars usually come in before the canine, so the canine is pushed toward the cheek when the arch is short. The old ADA name is cuspid.

Read on 24 October 2026. Sources: Craciunescu and others, Dental Anatomy and Morphology of Permanent Teeth, in Human Teeth, From Function to Esthetics (IntechOpen, 2023); Chussid, Anatomy of Primary Teeth, Columbia University College of Dental Medicine lecture; MolarPath note Eruption sequence and chronology (built on McDonald and Avery, 11th ed., and Proffit's Contemporary Orthodontics, 7th ed.); American Dental Association, Tooth development charts (primary and permanent). Figures are usual values, and teeth vary from person to person.

Local anesthesia

The anterior superior alveolar nerve supplies the pulp, and buccal infiltration at the apex is the usual injection. An infraorbital block also reaches the canine and the other anterior teeth.

The nasopalatine nerve supplies the palatal tissue in the canine region. The greater palatine nerve runs forward along the hard palate from its back part to the canine region.

Read on 24 October 2026. Sources: MolarPath note Maxillary techniques, local anesthesia (built on Malamed's Handbook of Local Anesthesia, 7th ed.). Figures are usual values, and teeth vary from person to person.

Clinical and exam points

The AAPD reports that the maxillary canine is impacted in one to three percent of the population, and that females are two to three times as likely as males to be affected. Impaction is suspected when the canine bulge cannot be felt, when the two sides erupt unevenly or when a peg-shaped lateral incisor is present.

A normally erupting canine should be palpable in the buccal sulcus by 10 to 11 years. Taking out the primary canine may stimulate eruption of the permanent one. The AAPD quotes a rate of 75 percent erupting after primary canine extraction when impaction is found at 11 to 16 years and the canine is not horizontal.

Read on 24 October 2026. Sources: American Academy of Pediatric Dentistry, Management of the Developing Dentition and Occlusion in Pediatric Dentistry (2024 revision); MolarPath note Eruption sequence and chronology (built on McDonald and Avery, 11th ed., and Proffit's Contemporary Orthodontics, 7th ed.). Figures are usual values, and teeth vary from person to person.

Questions and answers

Read on 24 October 2026. Sources: American Dental Association, Tooth development charts (primary and permanent); American Academy of Pediatric Dentistry, Management of the Developing Dentition and Occlusion in Pediatric Dentistry (2024 revision); MolarPath note Eruption sequence and chronology (built on McDonald and Avery, 11th ed., and Proffit's Contemporary Orthodontics, 7th ed.); Craciunescu and others, Dental Anatomy and Morphology of Permanent Teeth, in Human Teeth, From Function to Esthetics (IntechOpen, 2023). Figures are usual values, and teeth vary from person to person.