Primary maxillary lateral incisor: FDI 52 and 62

The numbers on both sides

In FDI the first digit is the quadrant and the second is the position counted from the midline. 52 is quadrant 5, position 2: the upper right primary lateral incisor. 62 is the same position in quadrant 6, on the upper left. Universal gives baby teeth the letters A to T, from the upper right second molar around to the lower right second molar, which makes this tooth D on the upper right and G on the upper left. Palmer writes the letter for the position inside a bracket that shows the quadrant. In plain text that gives URB and ULB.

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

Development and eruption

Calcification starts at about 16 weeks in utero, the crown is complete at 2.5 months and the tooth erupts at 9 to 13 months, usually in the second half of the first year or later. The root is done at 2 years and the tooth is shed at 7 to 8 years.

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); 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.

Crown

The lateral incisor is narrower than the central incisor, with a crown taller than it is wide. As with the central incisor, a cingulum and distinct marginal ridges enclose a shallow lingual fossa, and there are no mamelons or deep lobe grooves.

In a closed arch the two teeth meet the canine at the primate space, the gap most children have between the lateral incisor and the canine.

Read on 24 October 2026. Sources: MolarPath note Primary tooth morphology (built on McDonald and Avery's Dentistry for the Child and Adolescent, 11th ed.); Chussid, Anatomy of Primary Teeth, Columbia University College of Dental Medicine lecture. Figures are usual values, and teeth vary from person to person.

Roots and canals

The root is slim and conical, narrower from side to side than the crown. In the Salama study, 10 maxillary lateral incisors had canals of 15.0 mm on average (range 14 to 16 mm), shorter and slightly more variable in length than the central incisor's 16.5 mm. All had a single canal without bifurcation or accessory canals.

As in the central incisor, the canal curved toward the lip in the apical third to half of the root. The apical foramen usually sat near the anatomical apex.

Roots of primary teeth finish forming roughly 16 to 20 months after eruption. In about three years they begin to resorb at the apex or on a lateral surface near it, and dentin laid down inside the canal can change the number, size or shape of the canals.

Read on 24 October 2026. Sources: Salama and others, Anatomy of primary incisor and molar root canals, Pediatric Dentistry 14(2), 1992. Figures are usual values, and teeth vary from person to person.

Neighbors and the tooth that replaces it

A lateral incisor beside the canine marks the edge of the maxillary primate space, which lies between the lateral incisor and the canine and is present in most children. Spacing between the central incisors is a general physiologic space.

The permanent lateral incisor that follows is the tooth the AAPD names as the second most frequently missing permanent tooth after the mandibular second premolar, third molars excluded. That successor erupts at 8 to 9 years, after the central incisor.

Read on 24 October 2026. Sources: MolarPath note Primary tooth morphology (built on McDonald and Avery's Dentistry for the Child and Adolescent, 11th ed.); American Academy of Pediatric Dentistry, Management of the Developing Dentition and Occlusion in Pediatric Dentistry (2024 revision); American Dental Association, Tooth development charts (primary and permanent). Figures are usual values, and teeth vary from person to person.

Local anesthesia

The principle is the same as for the central incisor. In children the bone is thin and porous, so a buccal deposit reaches the pulp, and a slow injection reduces discomfort.

When palatal soft tissue must be numb, a small deposit in the attached gingiva is enough for one or two teeth. Palatal mucosa is bound tightly to bone, so the deposit goes in slowly.

Read on 24 October 2026. Sources: MolarPath note Mandibular techniques, local anesthesia (built on Malamed's Handbook of Local Anesthesia, 7th ed.); 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

Hypodontia is less frequent in the primary dentition than in the permanent one, under one percent, and it almost always affects the maxillary incisors and first primary molars. The AAPD adds that a missing primary tooth strongly predicts a missing permanent successor.

Supernumerary teeth in the primary dentition can displace or damage the permanent incisor. A mesiodens is a supernumerary tooth at the midline, and delayed eruption, an over-retained primary incisor or an unusual eruption pattern should raise suspicion of one.

Read on 24 October 2026. Sources: American Academy of Pediatric Dentistry, Management of the Developing Dentition and Occlusion in Pediatric Dentistry (2024 revision). 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); Salama and others, Anatomy of primary incisor and molar root canals, Pediatric Dentistry 14(2), 1992; MolarPath note Primary tooth morphology (built on McDonald and Avery's Dentistry for the Child and Adolescent, 11th ed.). Figures are usual values, and teeth vary from person to person.