When a baby molar has to come out years before the adult tooth beneath it is ready, the teeth on either side can lean or drift into the gap. A space maintainer is a small appliance that holds that gap open until the adult tooth arrives. Not every early loss needs one, and the decision depends on which tooth was lost, how old your child is and how far the adult tooth has developed.
Parents are often told a maintainer is needed straight away. The research is more mixed than that, which is why an individual assessment matters.
Why the timing of the loss matters
When a baby tooth falls out on schedule, the adult tooth is usually close behind and fills the space within weeks or months. An early loss is different. Baby molars removed because of decay, such as early childhood caries, infection or injury can leave a gap for a year or more, giving the neighbouring teeth time to move. The back teeth in particular tend to tip forward into an open space, which can reduce the room left for the adult tooth.
An X-ray helps the dentist see how far the adult tooth has formed and how much bone still covers it, which gives an idea of how long the space needs holding.
How much space is actually lost
Space loss varies by tooth and by jaw. A 2026 meta-analysis in BMC Oral Health (El-Motayam and colleagues) pooled studies of children aged 6 to 9 who lost a first baby molar early. On average, compared with the other side of the mouth, the space closed by about half a millimetre in the upper jaw over 9 to 12 months, and by nearly 1.8 millimetres in the lower jaw over 8 to 9 months. The authors suggested space maintainers are indicated after lower first baby molar extractions, while upper cases may not need one routinely.
Dentists are often more cautious when a second baby molar, the larger tooth just in front of the first adult molar, is lost early, because the adult molar behind it can drift forward. Even so, a 2023 systematic review in the European Journal of Orthodontics (Tabatabai and Kjellberg) found only limited evidence on space maintainers after second baby molar loss: they can preserve arch length, but they were also linked with more plaque around the appliance, and good quality long-term studies are lacking.
Kinds of space maintainers
Most are fixed in place, which means they work without a child having to remember to wear them. The design depends on how many teeth are missing and where.
| Design | Typically used for | How it holds the space |
|---|---|---|
| Band and loop | One missing baby molar | A metal band on the neighbouring tooth with a wire loop resting against the tooth on the other side of the gap |
| Crown and loop | A gap next to a tooth that also needs a crown | A stainless steel crown with a loop attached |
| Lingual arch | Missing lower baby molars on both sides | A wire behind the lower front teeth joining bands on molars on each side |
| Distal shoe | A second baby molar lost before the first adult molar has come through | A metal extension under the gum guides the adult molar as it erupts |
| Removable plate | Several missing teeth, or where a fixed design does not suit | An acrylic plate, which can also carry a replacement front tooth |
Removable plates suit some older children who will wear them reliably, and can fill a visible gap at the front. Their effect depends on being worn as instructed.
If the decision is not to fit one
Sometimes the dentist will advise watching the space instead, for example when the adult tooth is close to coming through, when there is already spare room in the arch, or after the loss of an upper first baby molar. In that case the space is checked at regular visits, and a maintainer can be reconsidered if it starts to close. Where a maintainer is advised but not fitted, drift can leave the adult tooth crowded, coming through out of line or stuck, which may need orthodontic treatment later.
Children of this age are also gaining other adult teeth, including their twelve-year molars, so the overall picture of the bite is looked at, not only the single gap.
Looking after the appliance
Food and plaque collect more easily around bands and wires, so brush carefully around the appliance every day and clean between the teeth. Avoid very sticky lollies and chewing ice or hard objects, which can bend or loosen it. Keep every review appointment, as the fit needs checking as your child grows. If the appliance comes loose, breaks or falls out, call the practice rather than waiting for the next check, since it stops holding the space as soon as it is out.
Habits can affect a developing bite as well. If your child shows signs of tongue thrust or an open bite, mention it at the same visit. After a knock to a permanent front tooth, see our guide to a chipped permanent front tooth.
What parents ask
How long does it stay in?
Usually until the adult tooth starts to come through, which may be months or a few years depending on how early the baby tooth was lost.
Is fitting one painful?
Fitting a band and loop is usually quick and does not normally need an injection, because the band is cemented around the outside of a tooth.
Will it mean my child avoids braces?
It can help keep space for the adult tooth that would otherwise be lost to drifting, but it does not prevent orthodontic problems with other causes, such as jaw size or tooth size.
Is it the same as a retainer?
No. A retainer holds teeth in place after orthodontic treatment. A space maintainer holds a gap open before the adult tooth has come through.
Booking a check for your child
If your child has lost a baby tooth early, an examination soon afterwards is the best way to find out whether a space maintainer would help. At Lumi Dental in Melrose Park our dentists and oral health therapists see children and families. Read more about general dental care for children or see our current offers.
This article is general information only and is not a substitute for an individual dental assessment.
