The answer has two halves, and the second half is why so many permanent teeth in children go unnoticed until they are badly damaged.
- All eight baby molars are replaced, generally between nine and twelve years old.
- The molar erupting at around six years at the very back is permanent and never replaced, because it is an addition rather than a replacement.
- Rule of thumb at home: only five baby teeth per side per jaw, so the sixth tooth from the middle is permanent.
- A decayed baby molar still needs treating, as it chews for years more and infection at its root sits above the permanent tooth bud below.
A child has decay in a back tooth and the family decides to leave it, on the basis that the tooth will be replaced anyway. Dentists meet this situation constantly, which is why this article needs to be blunt.
The short answer
Baby molars are replaced. A child has eight of them, four per jaw, and all eight come out to make way for the permanent premolars, generally between nine and twelve years old.
But the molar that arrives at around six years is not replaced. That one is a permanent first molar, erupting behind the existing row rather than replacing any baby tooth. Once it is through, it stays for life.
Why the two are so easily confused
Every other permanent tooth announces itself: a baby tooth loosens and falls out first. The six-year molar simply appears at the back of the existing row with nothing coming out beforehand. The child happens to be losing front teeth at the same time, so families assume everything further back is a baby tooth awaiting its turn.
There is a second reason. This tooth sits right at the back, hard to see and hard to brush, so it is both prone to decay and easy to overlook.
Telling them apart at home
Count backwards from the midline of the jaw. A child has only five baby teeth per side per jaw: two incisors, one canine and two molars. So:
- The fourth and fifth teeth from the middle are baby molars and will be replaced.
- The sixth, sitting immediately behind them at the very back, is a permanent tooth and will not be.
This gives you an estimate. Confirmation comes from the dentist at an examination, sometimes with an X-ray. What matters more than counting correctly: any decayed tooth needs attention, baby or permanent.
Does a decayed baby molar need treating?
Yes. Waiting for it to be replaced is a common mistake, for several reasons:
- Baby molars stay in use until around ten to twelve years, which is years away. Your child chews with them the whole time.
- Decay reaching the pulp causes pain, lost meals, broken sleep and missed school.
- Infection at the root of a baby tooth sits directly above the permanent tooth bud below and can affect the tooth on its way.
- A baby molar damaged badly enough to need removing leaves a space, and neighbouring teeth drift in, narrowing the room for the permanent tooth.
As for the six-year molar, waiting is not an option at all, since it is never replaced.
The health insurance side
Paediatric dental procedures such as treating dentine decay, root canal treatment on baby teeth, extraction of baby teeth and fissure sealing fall within the scope considered for health insurance cover when prescribed by the dentist. The level of cover depends on the category recorded on the child's card.
Children under six have their own health insurance card under the regulations. Bring the card or the VssID app together with identification when you come in.
Protecting the six-year molar
- Brush right to the back, where the new tooth sits behind the row of baby teeth and is easily missed.
- Use fluoride toothpaste in an amount suited to your child's age.
- Ask the dentist about fissure sealing for this tooth once it is fully through. It is a preventive technique for the deep grooves on the chewing surface.
- Keep up check-ups so decay is caught while it is still a small spot.
For an examination, Ky Hoa Dental is at 266A - 268, 3 Thang 2 Street, Hoa Hung Ward, Ho Chi Minh City, open Monday to Saturday.
Frequently asked questions
Do a child's baby molars fall out?
Yes. There are eight baby molars and all of them come out to make way for the permanent premolars, generally between nine and twelve years old. The exception is the molar that erupts at around six years right at the back, which is permanent and is never replaced.
How do I tell whether a back tooth is a baby tooth or permanent?
Count backwards from the midline. There are only five baby teeth per side per jaw, so the fourth and fifth from the middle are baby molars while the sixth, at the very back, is permanent. This gives an estimate; the dentist confirms it at an examination.
Can a decayed baby molar simply be left to fall out?
No. Baby molars stay in use until around ten to twelve years. Decay reaching the pulp causes pain, and infection at the root sits directly above the permanent tooth bud below. If the tooth has to come out early, the space also lets neighbouring teeth drift in.