When does tooth I come in and fall out?
The upper baby first molars usually come in at 13–19 months and fall out at 9–11 years (ADA). The AAPD chart gives 11–18 months to come in and 9–11 years to fall out.
In the ADA chart, they usually come in after the lower baby lateral incisors (10–16 months) and before the lower baby first molars (14–18 months), and they fall out at the same time as the lower baby first molars, after the lower baby lateral incisors (7–8 years) and before the lower baby canines (9–12 years).
Tooth I is replaced by tooth 12, the upper left first premolar, which usually comes in at 10–11 years (ADA). Under the gum, tooth I starts to harden in the 4th month of pregnancy and is fully formed by about 24–30 months (AAPD).
Cavities between tooth I and its neighbors
Decay between the baby molars is one of the more common reasons teeth drift and space is lost before the adult teeth arrive.
Cavities. The AAPD advises repairing decayed baby teeth when possible, rebuilding each tooth to its original shape so it keeps its place until the adult tooth is ready.
Removing it on purpose. Taking out the upper baby first molar has been reported to help the first premolar, and sometimes a stuck canine, come in.
The same tooth on the right side, tooth B, has its own section on a baby molar that fuses and sinks.
Where is tooth I?
Tooth I is in your child's upper jaw on their left side. It is the fourth tooth from the middle: start at the gap between the two top front teeth and count 4 teeth toward the back on their left side.
"Left" and "right" always mean the child's own sides, so when you face your child, tooth I is on your right.
In front of it (toward the middle) is tooth H, the upper left baby canine. Behind it is tooth J, the upper left baby second molar.
Its mirror twin on the right side is tooth B. The tooth in the same spot in the lower jaw is tooth L, the lower left baby first molar.
Dental charts show the patient's right side on the left, so tooth I sits on the right half of the top row. The letters continue across the top: upper left teeth run from F (the front tooth) to J (the back molar).
What does the upper baby first molar do?
Baby molars do the grinding for young children, and they keep room for the premolars that replace them. Baby teeth matter even though they fall out: children need them to chew, speak and smile, and they help the adult teeth come in correctly.
Adult premolars replace the baby molars, so this tooth is followed by the upper first premolar, not by a molar.
How many roots does tooth I have?
3 roots. Baby molar roots are thin and spread wide apart. The premolar that will replace the baby molar forms in the space between them.
When to call a dentist about tooth I
If a baby tooth is knocked loose or out in a fall, or your child has swelling, fever or pain, call your dentist. Never put a knocked-out baby tooth back in (Knocked-Out Tooth Rescue explains why). Swelling that makes it hard to breathe or swallow is an emergency: call 911.
Tooth I in FDI and Palmer notation
| System | Tooth I is written | What it means |
|---|---|---|
| Universal (ADA, used in the US) | I | Baby teeth are lettered A–T around the mouth, starting at the upper right back molar. |
| FDI / ISO 3950 (international) | 64 | First digit 6 = upper left quarter (baby teeth use 5–8); second digit 4 = fourth baby tooth from the middle. Said "six-four". |
| Palmer | └D (often typed ULD) | The └ bracket marks the upper left quarter; D = fourth baby tooth from the middle. |
Palmer stops at E. Palmer letters only run from A to E in each quarter, so an "I" can only be a Universal letter.
FDI baby teeth start with 5 to 8. The first digit 6 marks the upper left baby quarter, so FDI 64 can't be mixed up with an adult tooth.
Letters and numbers don't line up. I is letter 9 of the alphabet, but baby tooth I is replaced by adult tooth 12, not tooth 9.
All baby teeth in the upper left quarter
From the front of the mouth to the back:
| Universal | FDI | Palmer | Tooth |
|---|---|---|---|
| F | 61 | └A (ULA) | Baby central incisor |
| G | 62 | └B (ULB) | Baby lateral incisor |
| H | 63 | └C (ULC) | Baby canine |
| I | 64 | └D (ULD) | Baby first molar (this tooth) |
| J | 65 | └E (ULE) | Baby second molar |
The Tooth Number Chart & Converter converts any tooth between the three systems.
Tools for tooth I
- Teething Calculator: which baby teeth are due at your baby's age.
- Baby Teeth Tracker: log each tooth in and out.
- Kids Fluoride Calculator: how much toothpaste to use; the ADA says a rice-grain smear until age 3, then a pea-size amount.
- Tooth Fairy Calculator: what families give for a lost tooth.
- Dental Treatment Plan Decoder: plain English for treatment-plan shorthand like "#30 MOD comp".
Frequently asked questions
What tooth is letter I?
When does tooth I come in?
When does tooth I fall out?
Why fix a cavity in tooth I if it will fall out?
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.
- American Dental Association (MouthHealthy). Tooth Decay with Baby Bottles. Accessed October 26, 2026.
Last reviewed by the Dental Health Time editorial team, against the sources above. How we review.