If one of your child's back baby teeth looks like it is sitting lower than the teeth around it, as though it is slowly sinking into the gum, you may be looking at infraocclusion. It is more common than many parents realise, reported in roughly 1 to 9 percent of growing children, and it most often affects the lower first baby molars. In most cases it is not painful and not an emergency, but it does need watching, because the decision about whether to leave it or remove it depends on what is happening underneath.
Key takeaways
- Infraocclusion means a tooth sits below the normal biting level of its neighbours.
- It usually happens because the tooth has fused to the bone, a process called ankylosis.
- Lower first baby molars are the most commonly affected teeth.
- Many cases are simply monitored, often with a tapping test and X-rays.
- Removal is considered if the adult tooth below is being blocked or there is no adult tooth to follow.
The one question that guides treatment: is there an adult tooth underneath?
The single most important factor in deciding what to do is whether a healthy adult tooth is developing below the submerged baby tooth, and whether it can erupt normally. If a good successor is on its way and on track, a mildly submerged baby tooth can often be left to shed naturally. If there is no adult tooth, or the adult tooth is being pushed off course, the plan changes. An X-ray answers this question, which is why imaging guides the whole decision.
What infraocclusion actually is
As children grow, the jaw and the teeth around a baby molar keep developing and erupting. If one baby tooth has become locked to the bone, it cannot keep pace, so it appears to sink relative to its taller neighbours. The tooth has not actually moved down. Everything around it has moved up. The usual cause is ankylosis, where the normal cushioning ligament between tooth and bone disappears in places and the tooth fuses directly to the jaw. Heredity, past trauma and local disturbances may also play a part.
How a dentist spots it
Diagnosis combines what the dentist sees and feels with what the X-ray shows. A simple clue is the percussion test: tapping an ankylosed tooth gives a sharp, solid, higher-pitched sound compared with the duller, cushioned sound of a normal tooth. The dentist also grades how far below the bite the tooth sits and looks for tipping of the neighbouring teeth. An X-ray then shows whether the ligament space has been lost and, crucially, whether an adult tooth is present and where it is heading.
Why it matters
A mildly submerged baby tooth that sheds on time often causes no trouble at all. Problems arise when the tooth stays put too long or sinks too far. The neighbouring teeth can tip inwards over the gap, the opposing tooth can over-erupt looking for contact, food can pack around the sunken tooth, and in some cases the adult tooth below is diverted from its proper path. The more severe the infraocclusion and the longer it persists, the greater the chance of these knock-on effects on the bite.
How it is managed
Monitoring
For mild cases with a healthy successor on the way, the usual approach is watchful monitoring, often reviewing every six months or so to make sure the tooth sheds and the adult tooth erupts as expected.
Building up the tooth
If the tooth is sinking and food is trapping or the opposing tooth is over-erupting, the dentist may add a build-up to restore the biting surface temporarily and keep the space healthy until the tooth is ready to come out.
Removal
Extraction is considered when the tooth is severely submerged, when neighbouring teeth are tipping enough to block the successor, or when there is no adult tooth to replace it and a longer-term space plan is needed. Timing is chosen carefully with growth in mind, sometimes alongside an orthodontic plan.
| Situation | Usual approach |
|---|---|
| Mild, healthy adult tooth on track | Monitor and let it shed naturally |
| Food trapping or opposing tooth over-erupting | Build up the surface, keep monitoring |
| Severe submersion or successor blocked | Plan removal at the right time |
| No adult successor present | Removal plus a space or orthodontic plan |
General cost considerations in Australia
Monitoring infraocclusion mostly involves routine check-ups and the occasional X-ray. If a build-up or extraction is needed, those are separate procedures, and any orthodontic space management is planned on its own. As a general guide, a children's check-up sits around $60 to $120, an X-ray around $40 to $90, and a simple extraction varies with complexity. These are market ranges only, not a quote, and many children are eligible for support through the Child Dental Benefits Schedule. Lumi Dental does not publish its own prices here. See the offers page or ask for a written estimate.
Frequently asked questions
Is a submerged baby tooth painful?
Usually not. It is most often discovered at a check-up rather than because of pain, though food trapping can cause gum irritation.
Will it fix itself?
Mild cases with a healthy adult tooth often resolve when the baby tooth sheds normally. More severe cases tend to need help.
Does my child need an X-ray?
An X-ray is the key test, because it shows whether an adult tooth is present and whether it is being blocked, which decides the plan.
What happens if there is no adult tooth underneath?
The dentist will discuss keeping the baby tooth as long as it is useful, or removing it and managing the space, sometimes with orthodontic input.
Can adults have infraocclusion?
It is mainly a childhood finding in baby molars, but ankylosis can affect adult teeth too, especially after trauma.
Watch it, image it, then decide
A submerged baby tooth is rarely an emergency, but it deserves monitoring and an X-ray to check the adult tooth beneath. For related reading, see our guides to missing adult teeth in children and a child's first dental visit. To have your child's bite reviewed, contact the team at Lumi Dental.
This article is general information and not a substitute for an assessment by your child's dentist.
