Missing tooth 4
Leaving out wisdom teeth, the upper second premolar is the third most commonly missing adult tooth, after the lower second premolar and the upper lateral incisor.
If it never forms, the baby molar it should replace (tooth A) may stay in place longer.
Keeping the baby molar. It can be kept, or removed and the space closed with braces, filled with a replacement tooth, or filled with a tooth moved from elsewhere in the mouth (autotransplantation). Keeping a sunken (fused) baby molar for years can leave a dip in the bone that makes a later implant harder.
The same tooth on the left side, tooth 13, has its own section on root canals and the sinus.
Where is tooth 4?
Tooth 4 is in your upper jaw on your right side. It is the fifth tooth from the middle: start at the gap between the two top front teeth and count 5 teeth toward the back on your right side.
In a mirror, tooth 4 shows on the right side of your reflection. Someone looking into your mouth sees it on their left.
In front of it (toward the middle) is tooth 5, the upper right first premolar. Behind it is tooth 3, the upper right first molar.
Its mirror twin on the left side is tooth 13. The tooth in the same spot in the lower jaw is tooth 29, the lower right second premolar.
Dental charts show the patient's right side on the left, so tooth 4 sits on the left half of the top row. Universal numbers start here: upper right teeth run from 1 (the wisdom tooth) to 8 (the front tooth).
What does the upper second premolar do?
Premolars (also called bicuspids) sit between the canines and the molars and help crush and grind food. They have features of both their neighbors. The upper second premolar looks a lot like the first premolar beside it, but it usually has just one root.
It is also called the "second bicuspid".
Adult premolars replace the baby molars. There are no premolars among the 20 baby teeth.
How many roots does tooth 4 have?
Usually 1 root, sometimes 2.
When does tooth 4 come in?
Both the ADA and AAPD charts give 10–12 years for the upper second premolars.
Tooth 4 replaces the upper right baby second molar (tooth A), which usually falls out at 10–12 years (ADA).
In the ADA chart, they come in at the same time as the lower first premolars, after the upper first premolars (10–11 years) and before the upper canines (11–12 years). In the AAPD's 13-step order, from the first molars (step 1) to the wisdom teeth (step 13), they are step 9.
Under the gum, according to the AAPD chart, it starts to harden (calcify) at about 24–30 months, has a finished crown by 6–7 years and has a finished root by about 12–14 years, a few years after it comes into the mouth.
Common problems with upper second premolars
- Cavities in the grooves and between the teeth. Small cavities are fixed with a filling. If decay or an injury reaches the nerve, root canal treatment can save the tooth, often followed by a crown.
If tooth 4 hurts, feels loose, or the gum around it swells, the Dental Emergency Checker can help you decide how soon to see a dentist. Swelling that spreads to the eye or neck, or makes it hard to breathe or swallow, is an emergency: call 911. These are typical problems for this kind of tooth, not a diagnosis.
Tooth 4 in FDI and Palmer notation
| System | Tooth 4 is written | What it means |
|---|---|---|
| Universal (ADA, used in the US) | 4 | Adult teeth are numbered 1–32 around the mouth, starting at the upper right wisdom tooth. |
| FDI / ISO 3950 (international) | 15 | First digit 1 = upper right quarter; second digit 5 = fifth tooth from the middle. Said "one-five". |
| Palmer | 5┘ (often typed UR5) | The ┘ bracket marks the upper right quarter; 5 = fifth tooth from the middle. |
A lone "4" can only be Universal. FDI codes always have two digits, so 4 on its own is never an FDI number.
On a US chart, "15" is a different tooth. Universal 15 is the upper left second molar (tooth 15), so "tooth 15" only means this tooth when the chart uses FDI.
Palmer needs the bracket. Every quarter of the mouth has a tooth 5 in Palmer notation; only the ┘ (or the letters UR) makes it this one.
All adult teeth in the upper right quarter
From the front of the mouth to the back:
| Universal | FDI | Palmer | Tooth |
|---|---|---|---|
| 8 | 11 | 1┘ (UR1) | Central incisor |
| 7 | 12 | 2┘ (UR2) | Lateral incisor |
| 6 | 13 | 3┘ (UR3) | Canine |
| 5 | 14 | 4┘ (UR4) | First premolar |
| 4 | 15 | 5┘ (UR5) | Second premolar (this tooth) |
| 3 | 16 | 6┘ (UR6) | First molar |
| 2 | 17 | 7┘ (UR7) | Second molar |
| 1 | 18 | 8┘ (UR8) | Wisdom tooth |
The Tooth Number Chart & Converter converts any tooth between the three systems.
Tools for tooth 4
- Dental Emergency Checker: how soon to see a dentist if it hurts or breaks.
- Dental Numbness Calculator: how long numbness lasts after a filling.
- Dental Insurance Calculator: what your plan may pay for a crown or root canal.
- Adult Teeth Predictor: likely dates for your child's adult teeth.
- How Long Does Dental Work Last?: how long fillings, crowns, veneers and implants usually last, from long-term studies.
- Dental Treatment Plan Decoder: plain English for treatment-plan shorthand like "#30 MOD comp".
Frequently asked questions
What tooth is number 4?
Is tooth 4 the same as tooth 15?
At what age does tooth 4 come in?
What happens if tooth 4 never forms?
Sources
- American Dental Association (MouthHealthy). Permanent Tooth Development (eruption chart). 2012. Accessed October 26, 2026.
- American Dental Association (MouthHealthy). Primary Tooth Development (eruption chart). 2012. Accessed October 26, 2026.
- American Academy of Pediatric Dentistry. Dental Growth and Development (chronology after Logan & Kronfeld 1933, adapted 2003). Accessed October 26, 2026.
- American Academy of Pediatric Dentistry. Management of the Developing Dentition and Occlusion in Pediatric Dentistry (Reference Manual of Pediatric Dentistry). latest revision 2024. Accessed October 26, 2026.
- World Health Organization. Oral health surveys: basic methods, 5th edition (tooth notation after ISO 3950). 2013. Accessed October 26, 2026.
- Nelson SJ. Elsevier. Wheeler's Dental Anatomy, Physiology and Occlusion, 11th edition. 2019.
- American Dental Association. ADA Dental Claim Form (tooth designation systems). Accessed October 26, 2026.
- Dentalcare.com (continuing education course CE500). An Overview of Dental Anatomy: Types of Teeth and their Functions. Accessed October 26, 2026.
- Dentalcare.com (continuing education course CE500). An Overview of Dental Anatomy: Permanent Dentition. Accessed October 26, 2026.
- Cleveland Clinic. Teeth: Anatomy, Types, Function & Care. last updated January 26, 2023. Accessed October 26, 2026.
Last reviewed by the Dental Health Time editorial team, against the sources above. How we review.