Tooth Number 28: Lower Right First Premolar

Tooth 28: braces and the chin nerve

Removed for braces. First premolars are often the teeth removed when braces need more room.

Near a nerve opening. The nerve that gives feeling to the lower lip and chin leaves the jaw through a small opening (the mental foramen). A review of CBCT studies found it most often between the two lower premolars or below the second premolar. It is an important landmark for numbing shots, surgery and implants in this area.

The same tooth on the left side, tooth 21, has its own section on extra canals.

Where is tooth 28?

Tooth 28 is in your lower jaw on your right side. It is the fourth tooth from the middle: start at the gap between the two bottom front teeth and count 4 teeth toward the back on your right side.

In a mirror, tooth 28 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 27, the lower right canine. Behind it is tooth 29, the lower right second premolar.

Its mirror twin on the left side is tooth 21. The tooth in the same spot in the upper jaw is tooth 5, the upper right first premolar.

Dental charts show the patient's right side on the left, so tooth 28 sits on the left half of the bottom row. Lower right teeth finish the circle, from 25 (the front tooth) to 32 (the wisdom tooth).

What does the lower first 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 lower first premolar has a large, pointed cheek-side cusp and a small tongue-side cusp, so it looks a bit like a canine.

It is also called the "first bicuspid".

Adult premolars replace the baby molars. There are no premolars among the 20 baby teeth.

How many roots does tooth 28 have?

Almost always 1 root.

When does tooth 28 come in?

Both the ADA and AAPD charts give 10–12 years for the lower first premolars.

Tooth 28 replaces the lower right baby first molar (tooth S), which usually falls out at 9–11 years (ADA).

In the ADA chart, they come in at the same time as the upper second 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 8.

Under the gum, according to the AAPD chart, it starts to harden (calcify) at about 18–24 months, has a finished crown by 5–6 years and has a finished root by about 12–13 years, a few years after it comes into the mouth.

Common problems with lower first premolars

• Cavities. 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 28 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 28 in FDI and Palmer notation

"28" in FDI is a different tooth. Read as an FDI code, 28 means the upper left wisdom tooth (tooth 16 in Universal). Charts and X-ray reports from outside the US often use FDI, so check which system is in use.

"44" can only be FDI. Universal numbers stop at 32, so a tooth 44 on any chart is this tooth.

Palmer needs the bracket. Every quarter of the mouth has a tooth 4 in Palmer notation; only the ┐ (or the letters LR) makes it this one.

All adult teeth in the lower right quarter

From the front of the mouth to the back:

The Tooth Number Chart & Converter converts any tooth between the three systems.

Tools for tooth 28

• 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

Sources

1. American Dental Association (MouthHealthy). Permanent Tooth Development (eruption chart). 2012. Accessed October 26, 2026.
2. American Dental Association (MouthHealthy). Primary Tooth Development (eruption chart). 2012. Accessed October 26, 2026.
3. American Academy of Pediatric Dentistry. Dental Growth and Development (chronology after Logan & Kronfeld 1933, adapted 2003). Accessed October 26, 2026.
4. World Health Organization. Oral health surveys: basic methods, 5th edition (tooth notation after ISO 3950). 2013. Accessed October 26, 2026.
5. Nelson SJ. Elsevier. Wheeler's Dental Anatomy, Physiology and Occlusion, 11th edition. 2019.
6. American Dental Association. ADA Dental Claim Form (tooth designation systems). Accessed October 26, 2026.
7. Dentalcare.com (continuing education course CE500). An Overview of Dental Anatomy: Types of Teeth and their Functions. Accessed October 26, 2026.
8. Dentalcare.com (continuing education course CE500). An Overview of Dental Anatomy: Permanent Dentition. Accessed October 26, 2026.
9. Cleveland Clinic. Teeth: Anatomy, Types, Function & Care. last updated January 26, 2023. Accessed October 26, 2026.
10. Pelé A, Berry PA, Evanno C, Jordana F. Radiology Research and Practice 2021:8897275. Evaluation of Mental Foramen with Cone Beam Computed Tomography: A Systematic Review of Literature. 2021. Accessed October 26, 2026.

Last reviewed October 26, 2026 by the Dental Health Time editorial team, against the sources above. How we review.