Tooth Number 30: Lower Right First Molar

Crown, filling or implant for tooth 30

After a root canal. The tooth is restored with a crown or filling for protection.

Why a crown matters. In a study of 203 root-canal-treated teeth, those left without a crown were lost at about 6 times the rate of crowned teeth. In another study of 119 root-canal-treated teeth that were later pulled, a lower first molar without a crown was the tooth removed most often.

One study singled out this tooth. In a review of 1,748 root-canal-treated teeth, the lower right first molar (tooth 30) was the single most often treated tooth (11.3%).

Replacing a lost molar. An implant is one option. A review of 18 studies found that 96.4% of implants were still in place after 10 years.

The same tooth on the left side, tooth 19, has its own section on cavities, sealants and root canals.

Where is tooth 30?

Tooth 30 is in your lower jaw on your right side. It is the sixth tooth from the middle: start at the gap between the two bottom front teeth and count 6 teeth toward the back on your right side.

In a mirror, tooth 30 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 29, the lower right second premolar. Behind it is tooth 31, the lower right second molar. When it first comes in at about age 6, the tooth in front of it is usually still the baby second molar (tooth T), which the second premolar replaces years later.

Its mirror twin on the left side is tooth 19. The tooth in the same spot in the upper jaw is tooth 3, the upper right first molar.

Dental charts show the patient's right side on the left, so tooth 30 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).

When does tooth 30 come in?

The lower first molars usually come in at 6–7 years according to the ADA chart. The AAPD chart gives 5.5–7 years.

In the ADA chart, they are among the first to come in, along with the upper first molars and the lower central incisors. In the AAPD's 13-step order, from the first molars (step 1) to the wisdom teeth (step 13), they are step 1.

Under the gum, according to the AAPD chart, it starts to harden (calcify) around birth, has a finished crown by 30–36 months and has a finished root by about 9–10 years, a few years after it comes into the mouth.

What does the lower first molar do?

Molars do the heavy grinding. Cleveland Clinic notes that about 90% of chewing happens on the molars. Molars have broad, flat chewing surfaces with 4–5 cusps (points) and the largest crowns of any teeth. The lower first molar is the largest tooth in the lower jaw, usually with five cusps.

It is also called the "6-year molar". First molars are named for the age they usually arrive, about 6 years.

Adult molars don't replace any baby tooth. They come in behind the baby teeth as the jaw grows.

How many roots does tooth 30 have?

2 roots, one at the front (mesial) and one at the back (distal). A review of 18,781 teeth found a third root in 13%, much more often in some ethnic groups.

Common problems with lower first molars

• Treatment. 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 30 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 30 in FDI and Palmer notation

There is no FDI tooth 30. In FDI the second digit only runs from 1 to 8, so 30 can only be a Universal number.

"46" can only be FDI. Universal numbers stop at 32, so a tooth 46 on any chart is this tooth.

Palmer needs the bracket. Every quarter of the mouth has a tooth 6 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 30

• Adult Teeth Predictor: likely dates for your child's adult teeth.
• Dental Emergency Checker: how soon to see a dentist if it hurts or breaks.
• Dental Numbness Calculator: lower molars usually get a nerve block, which lasts longer (about 3–3½ hours with lidocaine, vs about 2½ hours for a shot by the tooth).
• Dental Insurance Calculator: what your plan may pay for a crown or root canal.
• 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 Academy of Pediatric Dentistry. Dental Growth and Development (chronology after Logan & Kronfeld 1933, adapted 2003). Accessed October 26, 2026.
3. World Health Organization. Oral health surveys: basic methods, 5th edition (tooth notation after ISO 3950). 2013. Accessed October 26, 2026.
4. Nelson SJ. Elsevier. Wheeler's Dental Anatomy, Physiology and Occlusion, 11th edition. 2019.
5. American Dental Association. ADA Dental Claim Form (tooth designation systems). Accessed October 26, 2026.
6. Dentalcare.com (continuing education course CE500). An Overview of Dental Anatomy: Types of Teeth and their Functions. Accessed October 26, 2026.
7. Dentalcare.com (continuing education course CE500). An Overview of Dental Anatomy: Permanent Dentition. Accessed October 26, 2026.
8. Cleveland Clinic. Teeth: Anatomy, Types, Function & Care. last updated January 26, 2023. Accessed October 26, 2026.
9. American Association of Endodontists. What is a Root Canal?. Accessed October 26, 2026.
10. U.S. FDA label via DailyMed (Dentsply). XYLOCAINE Dental (lidocaine HCl and epinephrine) injection. updated August 13, 2026. Accessed October 26, 2026.
11. de Pablo OV, Estevez R, Péix Sánchez M, Heilborn C, Cohenca N. Journal of Endodontics 36(12):1919–1931. Root anatomy and canal configuration of the permanent mandibular first molar: a systematic review. 2010. Accessed October 26, 2026.
12. Yousuf W, Khan M, Mehdi H. International Journal of Dentistry 2015:673914. Endodontic Procedural Errors: Frequency, Type of Error, and the Most Frequently Treated Tooth. 2015. Accessed October 26, 2026.
13. Aquilino SA, Caplan DJ. Journal of Prosthetic Dentistry 87(3):256–263. Relationship between crown placement and the survival of endodontically treated teeth. 2002. Accessed October 26, 2026.
14. Touré B et al. Journal of Endodontics 37(11):1512–1515. Analysis of reasons for extraction of endodontically treated teeth: a prospective study. 2011. Accessed October 26, 2026.
15. Howe MS, Keys W, Richards D. Journal of Dentistry 84:9–21. Long-term (10-year) dental implant survival: A systematic review and sensitivity meta-analysis. 2019. Accessed October 26, 2026.
16. Almadhoon HW, Abuiriban RW, Almassri H, Al-Hamed FS. Journal of Evidence-Based Dental Practice 22(2):101712. Efficacy of 4% articaine buccal infiltration versus inferior alveolar nerve block for mandibular molars with symptomatic irreversible pulpitis: a systematic review and meta-analysis. 2022. Accessed October 26, 2026.

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