Maxillary first premolar: FDI 14 and 24
The upper first bicuspid: two cusps, a mesial depression that runs onto the root and usually two roots.
Quick answer
- FDI 14 and 24, Universal 5 and 12, Palmer UR4 and UL4.
- Maxillary first premolar erupts at 10 to 11 years.
The numbers on both sides
| Tooth | FDI | Universal | Palmer |
|---|---|---|---|
| Upper right first premolar | 14 | 5 | UR4 |
| Upper left first premolar | 24 | 12 | UL4 |
In FDI the first digit is the quadrant and the second is the position counted from the midline. 14 is quadrant 1, position 4: the upper right first premolar. 24 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 5 on the upper right and 12 on the upper left. Palmer writes the position inside a bracket that shows the quadrant. In plain text that gives UR4 and UL4.
A plain number can name two different teeth, so the system matters. Universal 14 is the maxillary left first molar, which is FDI 26. Universal 24 is the mandibular left central incisor, which is FDI 31.
Crown surfaces: mesial, distal, buccal, palatal (lingual) and occlusal.
The ADA chart also uses the older name first bicuspid.
Development and eruption
| Stage | Age |
|---|---|
| Calcification begins | 1.5 to 1.75 years |
| Crown completed | 5 to 6 years |
| Erupts | 10 to 11 years |
| Root completed | 12 to 13 years |
Calcification starts between 1.5 and 1.75 years and the crown is complete at 5 to 6 years. The tooth erupts at 10 to 11 years, ahead of the canine in the upper arch, and the root closes at 12 to 13 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). Figures are usual values, and teeth vary from person to person.
Crown
The occlusal outline is hexagonal, and the crown is wider cheek to tongue than front to back. Two cusps carry the occlusal table. The buccal cusp is sharper, longer and wider, and it stands about 1 mm or more above the lingual cusp, which is the shortest of the four upper premolar cusps.
A transverse ridge joins the two cusps. A central developmental groove runs between them and ends in a mesial pit and a distal pit, with few supplemental grooves.
The feature that separates it from the second premolar is on the mesial side: a mesial developmental depression and a mesial marginal groove.
Read on 24 October 2026. Sources: Nagas and others, The Permanent Maxillary and Mandibular Premolar Teeth, in Dental Anatomy (IntechOpen, 2018). Figures are usual values, and teeth vary from person to person.
Roots and canals
Ingle's Endodontics tabulates one or two roots and two canals. The two-rooted form has a buccal and a palatal root that separate in the middle or apical third, and the palatal root is smoother with a blunter tip. The pooled review of 86 studies and 31,325 teeth reports two roots in a range from 7.1 to 96.2 percent across populations, so no single figure applies everywhere.
The most common canal pattern in that review was 2-2-2/2 (Vertucci type IV), followed by a single canal from orifice to apex. The root is about 3 to 4 mm shorter than the canine's root.
Read on 24 October 2026. Sources: Number of roots and canals, from Ingle's Endodontics (animated-teeth.com); Nagas and others, The Permanent Maxillary and Mandibular Premolar Teeth, in Dental Anatomy (IntechOpen, 2018); Wolf and others, Maxillary First Premolars' Internal Morphology: A Systematic Review and Meta-Analysis, Dentistry Journal 2025; 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
The crown is larger than the second premolar's, and its cusp lengths differ more. Its mesial depression has no equivalent on the second premolar. Compared with the canine, the crown is shorter cervico-occlusally.
The first premolar replaces the primary maxillary first molar, an atypical tooth with three or four cusps and a prominent mesiobuccal cervical bulge. The premolar crown forms between the divergent roots of the primary molar.
Read on 24 October 2026. Sources: Nagas and others, The Permanent Maxillary and Mandibular Premolar Teeth, in Dental Anatomy (IntechOpen, 2018); 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.
Local anesthesia
The middle superior alveolar nerve supplies the premolars when it is present. It is not present in every person, so the injection is chosen when premolar or first molar root sensitivity points to it. The middle superior alveolar block goes in at the height of the fold above the second premolar.
The anterior middle superior alveolar injection, a palatal technique near the premolar apices, is another route. 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 mesial concavity affects restorations. A flat matrix band spans the hollow and leaves the gingival margin open unless it is burnished and wedged or replaced by a contoured matrix. The same hollow makes plaque control and root instrumentation harder.
Premolars erupt sooner when a primary molar is lost: removing a primary molar speeds the eruption of the premolar beneath it once the premolar root is half to two thirds formed, but earlier removal lets bone grow over the crypt and delays it.
Read on 24 October 2026. Sources: MolarPath note Permanent tooth morphology (built on Wheeler's Dental Anatomy, 11th ed., and Sturdevant's Operative Dentistry, 8th ed.); 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
What are the numbers for the maxillary first premolar?
FDI 14 and 24, Universal 5 and 12, Palmer UR4 and UL4. The ADA also uses the name first bicuspid.
How many roots does it have?
Often two, a buccal and a palatal root. Studies range widely, from 7.1 to 96.2 percent two-rooted, depending on the population.
How do I tell it from the second premolar?
Look for the mesial developmental depression and mesial marginal groove, which only the first premolar has, and for the larger difference in cusp length.
When does it erupt?
The ADA chart gives 10 to 11 years.
Read on 24 October 2026. Sources: American Dental Association, Tooth development charts (primary and permanent); Wolf and others, Maxillary First Premolars' Internal Morphology: A Systematic Review and Meta-Analysis, Dentistry Journal 2025; Nagas and others, The Permanent Maxillary and Mandibular Premolar Teeth, in Dental Anatomy (IntechOpen, 2018). Figures are usual values, and teeth vary from person to person.
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