Gaps between baby teeth are usually a good sign: baby teeth are smaller than the adult teeth that will replace them, so a spaced toddler smile means the jaw is already holding room for what comes next. Better Health Channel describes gaps between baby teeth as very normal, and in a study of 1,000 preschool children published in the International Journal of Clinical Pediatric Dentistry, 81% had spaced baby teeth while 19% had teeth touching all the way around. The gaps that deserve a closer look sit in a single spot.
Written by Dr James Tran, BDent (University of Sydney), MICOI, GradDip (Oral Implants), general dentist at Lumi Dental in Melrose Park.
The short version
- Even, all-round gaps between a toddler's baby teeth are normal and favourable. The wider adult teeth will use that room.
- Two larger gaps, beside the upper canines and behind the lower canines, are called primate spaces and are part of the design.
- Research has reported that spaced baby teeth make crowding of the upper adult teeth less likely, though not impossible.
- A gap in one spot only can mean a missing, lost or extra tooth, or a low lip fraenum. That one is worth a check.
- No gaps at all is not an emergency, but it is the pattern a dentist watches as the adult teeth arrive.
- This covers ages one to six. Gaps between new adult front teeth at seven or eight are covered in our guide to the ugly duckling stage.
Why baby teeth come with spaces built in
There are 20 baby teeth and 32 adult teeth, and the adult front teeth and canines are noticeably wider than the baby teeth they replace. The jaw grows through childhood, but not enough to fit the larger set on its own, so spaces in the baby smile are part of the preparation. Better Health Channel lists natural development first among the causes of gapped teeth, and our article on how baby teeth differ from adult teeth explains why the two sets are built so differently.
Dentists sort baby smiles into two types, a classification credited to Baume. A spaced or open arch has visible gaps between some or all of the teeth; a closed arch has every tooth touching its neighbour. Spaced is the more common: the Bengaluru study put it at 81% of children under six, and across ethnic groups the proportion has ranged from around 42% to 98%.
Primate spaces and leeway space: how the gaps get used
Primate spaces
Two gaps are so consistent that they have a name. In the upper jaw the primate space sits between the baby lateral incisor and the canine; in the lower jaw it sits behind the canine. When the first adult molars push through at around six, the baby molars can shift into these gaps, which helps the back teeth settle into a good bite.
Leeway space
The baby canine and two baby molars on each side are together slightly wider than the adult canine and two premolars that replace them; orthodontists call the difference leeway space. Nance's classic figures, quoted in a Contemporary Clinical Dentistry review, are about 0.9 mm per side in the upper jaw and 1.7 mm per side in the lower, and the amount varies between children. That margin often lets slightly crowded adult front teeth straighten themselves between ten and twelve.
What spacing predicts
A five-year study in the Journal of Dentistry for Children followed 128 children into the mixed dentition. Those with a spaced arch and primate spaces were more likely to avoid crowding of the upper teeth, yet 29% still developed lower front crowding. In my experience parents hear "the gaps are good" and relax completely; the fuller version is that the gaps are good and we still look again at seven.
When a gap means something else
A single gap, with the rest of the teeth in contact, has a shorter list of causes.
A tooth that never formed
Hypodontia, a tooth missing from birth, is uncommon in baby teeth: a review in the International Journal of Dentistry puts it at under 1% of children in European-background populations, mostly the upper lateral and lower central incisors. The adult tooth beneath is often missing too, so an X-ray at the right age lets the family plan ahead.
A tooth lost early
A baby tooth lost to decay or a fall leaves a space the neighbours may drift into. For a front tooth that is rarely a problem. For a baby molar lost well before its time, the first adult molar can tip forward and use up the leeway space, which is when a dentist may suggest one of the space maintainers for children described in our guide.
An extra tooth or a low fraenum
Better Health Channel also lists extra teeth in the bone, which can block a neighbour from coming through, and the fraenum, the fold of tissue inside the upper lip. In babies it often attaches low and the two top front teeth sit apart; by the first birthday more teeth have usually closed the gap. A thick fraenum that persists is watched, not treated, in a toddler.
The single rule: even gaps everywhere, relax; one gap in one place, book a check
Parents often send me a phone photo. It can show that a gap exists, but not why: it cannot tell a missing tooth from a late one, and no dentist should diagnose from it. Spacing on both sides, with no single wide gap, needs no appointment of its own. One gap that stands out, or one that appeared after a knock or a toothache, deserves a chair, a mirror and sometimes a small X-ray.
No gaps at all: the smile a dentist watches
A toddler whose baby teeth all touch is not in trouble; about one in five preschoolers in the Bengaluru study had this closed pattern. The point is what comes next: if the smaller baby teeth already fill the arch, the wider adult teeth are more likely to arrive crowded or rotated. The Bengaluru authors quote Leighton's rule of thumb that around 6 mm of total spacing across the lower baby teeth is needed before lower incisor crowding becomes unlikely. A closed arch earns regular reviews through primary school so the family hears about options early.
Habits that change spacing
A thumb or dummy held between the front teeth for long stretches tends to push the upper front teeth forward and apart, so a thumb-sucker may have an exaggerated front gap that is not a sign of extra room. Most of this corrects itself once the habit stops before the adult front teeth arrive. Our guide to thumb sucking and teeth covers timing and gentle ways to stop.
Gap patterns at a glance
| Gap pattern in a toddler | Usual meaning | What to do |
|---|---|---|
| Small, even gaps between most teeth | Normal developmental spacing | Routine check-ups |
| Larger gap beside each upper canine and behind each lower canine | Primate spaces, normal | Nothing extra |
| Gap between the top two front teeth in a baby | Often a low fraenum; usually closes | Mention at the first visit |
| One gap in one place, other teeth touching | Possible missing, late, extra or lost tooth | Book a check; an X-ray may be suggested |
| Front teeth pushed forward and apart | Thumb or dummy habit | Stop the habit before the adult front teeth arrive |
| No gaps at all | Closed arch; adult crowding more likely | Regular reviews through primary school |
When to see a dentist about your toddler's teeth
The Raising Children Network advises a first check by about 12 months or when the first tooth comes through, whichever happens first, then every six to twelve months. That first visit is short and mostly conversation, and it is when spacing is first noted, so a closed arch or a single odd gap has a record to compare against later. The Child Dental Benefits Schedule covers basic dental care for eligible children aged 0 to 17.
How we approach this at Lumi Dental
At a children's check-up at Lumi Dental the dentist examines and diagnoses, counting the teeth, noting the spacing pattern and checking for decay, while the hygiene team of oral health therapists works with parents on cleaning and diet. Where a single gap raises the question of a missing or extra tooth, the team may suggest a small X-ray when the child is old enough for it to show the answer. The whole practice accepts the Child Dental Benefits Schedule for eligible children, and children who need specialist care are referred to a paediatric dentist or orthodontist; see children's dentistry at Lumi Dental.
Questions patients ask
Is it normal for toddlers to have gaps between their teeth?
Yes. Spacing is the most common pattern in the baby smile; in a large study of preschoolers around four in five children had it. The gaps hold room for the wider adult teeth.
Will the gaps in my child's baby teeth close?
Most are used up rather than closed: the baby molars shift into the primate spaces and the wider adult front teeth fill the rest. Gaps between new adult front teeth usually close when the adult canines arrive; if one remains, our article on gaps between the front teeth covers the options.
Is a gap between my baby's two front teeth a problem?
Usually not. Better Health Channel notes that when the first teeth arrive at around six to nine months the fraenum is often attached low and the front teeth sit apart; by the first birthday more teeth have usually closed the gap.
Does no gaps between baby teeth mean braces later?
Not necessarily, but it raises the odds. Crowding is more likely when the baby teeth already touch, so a dentist reviews a closed arch more closely from about age seven.
When should my toddler first see a dentist?
By about 12 months or when the first tooth comes through, whichever is first. Our guide to a child's first dental visit explains what happens.
Book your child's check-up at Lumi Dental in Melrose Park
If you have noticed a gap you are unsure about, the team at Lumi Dental sees families from Melrose Park, Ryde, Parramatta, Ermington and Rydalmere at Melrose Central, with on-site parking. Read about children's dentistry at Lumi Dental, check eligibility under the Child Dental Benefits Schedule, or see our current offers.
Sources
- Vinay S and colleagues. Prevalence of spaced and closed dentition and its relation to malocclusion in primary and permanent dentition. International Journal of Clinical Pediatric Dentistry (PMC)
- Vyas MB and Hantodkar N. Resolving mandibular arch discrepancy through utilization of leeway space. Contemporary Clinical Dentistry (PMC)
- Better Health Channel: Teeth, gapped teeth
- Raising Children Network: Toddler teeth development, dental health and dental care
About the author
Dr James Tran is a general dentist at Lumi Dental in Melrose Park. He holds a BDent from the University of Sydney and a Graduate Diploma in Oral Implants, and is a Member of the International Congress of Oral Implantologists (MICOI).
This article is general information only and is not a substitute for an examination and individual advice from a registered dental practitioner. Suitability for any treatment varies from person to person.
