Baby tooth K is the lower left second molar in the baby (primary) teeth. In the FDI (ISO 3950) system it is 75, and in Palmer notation it is ┌E. It usually comes in at 23-31 mos and falls out at 10-12 yrs.
Tooth K at a glance
| Universal (US) | K |
| FDI / ISO 3950 | 75 |
| Palmer | ┌E |
| Name | Lower left second molar |
| Type | Second molar (baby tooth) |
| Jaw | Lower (mandible) |
| Side | Patient’s left |
| Comes in | 23-31 mos |
| Falls out | 10-12 yrs |
| Roots | 2, widely spread |
| Root canals (usual) | usually 3 |
| Chewing surface | 5 cusps |
Where it is and what it does
It sits in the lower jaw on the patient’s left side, fifth from the midline. Baby molars do most of a young child’s chewing. They also hold the space for the adult premolars that will grow in underneath them, so losing one early can let neighbouring teeth drift.
Neighbouring and related teeth
- In front of it (toward the midline): Baby tooth L, the lower left first molar
- Same tooth on the other side: Baby tooth T
- The matching tooth in the upper jaw: Baby tooth J
- Replaced by: Tooth number 20, the lower left second premolar (adult premolars replace baby molars)
Common dental work on this tooth
Baby molars can get cavities between them and in the grooves on top, so dentists often check them closely. Treatments include fillings, sealants and small crowns. If a baby molar is lost early, a space maintainer may be used to keep room for the adult tooth.
Questions
What tooth is letter K?
Baby tooth K is the lower left second molar (a baby tooth). Letters A to T are used for baby teeth in the Universal system used in the United States.
What is baby tooth K in the FDI and Palmer systems?
In FDI it is 75, said digit by digit (“seven-five”). The first digit is the quadrant and the second is the position from the midline. In Palmer notation it is ┌E.
When does baby tooth K fall out?
Usually at about 10-12 yrs, when the adult lower left second premolar pushes it out from underneath. It first comes in at about 23-31 mos.
For education only. This is not dental advice; your dentist can tell you what is right for your own teeth.