The ugly duckling stage is a normal phase, usually seen somewhere between about 8 and 12 years of age, when new upper front teeth come through with gaps or at an angle and then settle as the rest of the adult teeth arrive. Parents often see it for the first time in school photos and wonder whether braces are already needed. In most children, the ugly duckling stage teeth are simply part of development, and the picture changes a great deal once the canines come through. Cleveland Clinic notes that a gap in a child's teeth commonly closes once the adult teeth are in.
By Dr James Tran, BDent (University of Sydney), Graduate Diploma in Oral Implants. General information for parents.
The short version
- The ugly duckling stage is a temporary mismatch of tooth size, spacing and angle while a child has a mix of baby and adult teeth.
- It is commonly described between about 8 and 12 years, though children vary and a range is normal.
- A gap between the upper front teeth often narrows when the upper canines come through, so treatment is usually not started during the gap.
- Crowding, a bite that does not meet properly, or teeth that look worse over several months are reasons for a closer look.
- Orthodontic treatment is provided by registered specialist orthodontists, and a general dentist can tell you whether a referral is worthwhile. Our guide to the first orthodontic check explains the timing.
- Regular check-ups and good brushing matter more at this age than any appliance.
What the Ugly Duckling Stage Is
Children go through a period when baby teeth and adult teeth share the mouth. The adult front teeth are noticeably wider than the baby teeth they replace, and they arrive before the jaw has finished growing. The upper incisors often erupt with a space between them and may tip slightly outwards, which is the look parents describe as a gap or buck teeth.
The name comes from the Hans Christian Andersen story. It is a lighthearted label, not a diagnosis. In my experience, many of the children I see at this age are far more settled about their smile than their parents are, and what helps most is a calm explanation of what is happening.
Why Gaps and Angles Appear
The canines are still to come
The upper canines are among the last baby teeth to be replaced. Typical ranges put baby canines coming out at around 9 to 12 years, with the adult canines following. As the adult canine moves down beside the upper side teeth, it is commonly described as pressing the roots of the front teeth towards each other. That pressure often closes a gap that looked large a year earlier, which is why dentists tend to wait.
Size mismatch
New teeth are wider than the baby teeth before them, and the jaw is still growing to make room. Sometimes this looks like crowding, and sometimes like spacing, depending on the child's jaw and tooth size. Our article on the timing of baby tooth loss sets out the usual order, which helps explain why the front of the mouth changes first.
Inherited traits and habits
Some gaps are inherited, linked to small teeth, a missing tooth or a thick band of tissue between the lip and gum called the frenum. Habits such as thumb sucking or tongue thrust can also keep a gap open. See our notes on thumb sucking and teeth if that applies at home.
Normal Pattern or Worth Checking?
This table is a general guide. Only an examination, and sometimes an X-ray, can say what applies to your child.
| What you see | Often part of normal development | Worth raising with a dentist |
|---|---|---|
| Gap between upper front teeth, age 8 to 11 | Yes, it commonly narrows when canines arrive | If it is very wide, or one tooth is missing |
| Upper front teeth tipped outwards | Often, during the mixed stage | If a tooth sticks out far enough to be at risk of injury |
| Crowding of lower front teeth | Common as new teeth arrive | If it keeps worsening or a baby tooth will not loosen |
| Adult tooth behind a baby tooth | Common | If the baby tooth stays firm for several weeks |
| Upper and lower teeth not meeting properly | Not typical | Yes, ask for an assessment |
| Teeth that look worse over many months, with no canines in sight | Not typical | Yes, an X-ray may be needed |
| Child is worried about how their teeth look | Understandable | Yes, a chat can help |
The One Rule: Watch, Do Not Rush
A simple rule for most families is to avoid judging a smile until the canines and premolars have come through. Closing a gap early can mean the teeth drift apart again, or leave too little room for the canines. That does not mean ignoring the mouth. It means checking at regular visits and acting when there is a reason, such as a bite problem, a blocked tooth or an injury risk.
When an Orthodontic Opinion Makes Sense
Orthodontics Australia suggests a first visit to an orthodontist at around age 7, even if braces are not needed yet, so that early problems can be picked up. The Orthodontists, an Australian practice, similarly suggest an evaluation between roughly 8 and 10 years. Those are general guides rather than a rule that every child needs treatment.
Common reasons to seek an opinion include a crossbite, a bite where the upper teeth sit well forward of the lower, teeth that are crowded enough to trap an adult tooth, or an adult tooth that has not appeared when its partner on the other side has. Our overview of early orthodontic treatment for children explains what phase one treatment can and cannot do.
Orthodontic treatment is carried out by a registered specialist orthodontist. A general dentist can monitor, explain and refer. Lumi Dental does not have specialist orthodontists on staff, so where braces or jaw-guiding appliances are likely to be useful, we refer to a registered specialist.
What Parents Can Do in the Meantime
- Keep brushing with fluoride toothpaste and supervise it, because crowded and partly erupted teeth hold plaque easily.
- Ask about fissure sealants on new adult molars as they come through.
- Protect front teeth during sport with a mouthguard if they sit forward.
- Avoid comparing your child with classmates. Eruption timing differs widely between children of the same age.
- Do not use home gap-closing devices such as rubber bands. They can move teeth in ways that damage gums and bone.
If you have a specific gap in mind, such as one that persists in adults, our article on gaps between the front teeth compares the options.
How we approach this at Lumi Dental
The team at Lumi Dental includes dentists and oral health therapists, who work closely with children and families. At a child's check-up we look at the teeth that have come through, how the upper and lower teeth meet, and what is still to come, and we explain it in plain language. The team accepts the Child Dental Benefits Schedule for eligible children, and you can read how it works in our CDBS guide. Where a child may benefit from orthodontic care, we refer to a registered specialist.
Questions patients ask
How long does the ugly duckling stage last?
It typically lasts a couple of years, and is commonly described as running from about 8 to 12 years. It tends to settle as the canines and remaining adult teeth come through, although timing varies.
Will the gap between my child's front teeth close by itself?
Often, yes. Cleveland Clinic notes that many gaps in children close once the adult teeth arrive, though a larger gap may remain. A dentist can say whether yours is likely to.
Does my child need braces during the ugly duckling stage?
Usually not at this point. Treatment is more often planned once most adult teeth are in, unless there is a bite problem or a blocked tooth. A registered orthodontist makes that call.
Can thumb sucking cause the gaps?
It can contribute by pushing the front teeth forward or keeping a gap open. If the habit continues, mention it at the next check-up.
When should I book a dental check for my child's front teeth?
Keep to regular check-ups, and book sooner if a tooth is knocked, painful, very protruding or crowded enough to block another tooth. Our general dental team can look and advise.
Book a Child's Check at Lumi Dental
If you would like someone to look at your child's smile and explain what is normal, the team at Lumi Dental in Melrose Park can help. Visit general dentistry in Melrose Park to book, or see current deals for new patient offers. Families visit from Ryde, Parramatta, Ermington and Rydalmere.
Sources
- Cleveland Clinic: Diastema, definition, causes and treatment
- Orthodontics Australia: Orthodontic care for children
- The Orthodontists: When should children lose their baby teeth
- Australian Government Department of Health: Child Dental Benefits Schedule
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. This article is general information and is not a substitute for individual advice from a dentist who has examined you.
