Thumb Sucking and Dummies: When Should Parents Worry About Teeth?
- Star Light Dental
- July 2, 2026
- [email protected]
Sucking is one of the first things a baby learns to do, and for many babies a thumb, a finger or a dummy becomes the main way of settling themselves. It is completely normal, and most children give it up without any help somewhere between two and four.
The question parents ask is when it starts to matter for teeth. The answer comes down to three things: age, how often, and how hard.
1. When Does It Become a Problem?
In babies and toddlers, sucking habits do no lasting harm. Any changes to the baby teeth usually correct themselves once the habit stops. The age to watch is around four to five. If the habit is still going strong when the adult front teeth begin to arrive at about six, the changes are much more likely to become permanent.
Intensity matters as much as age. A child who rests a thumb passively in the mouth does far less damage than one who sucks hard for hours, including through the night.
2. What It Can Do to Teeth and Jaws
- An open bite: the top and bottom front teeth do not meet when the back teeth are together, leaving a gap the shape of the thumb.
- Front teeth pushed forward and lower front teeth tipped back.
- A narrowed upper jaw, which can lead to a crossbite at the back.
- Changes to speech, such as a lisp, and a tongue that pushes forward when swallowing.
3. Dummy or Thumb: Which Is Better?
Neither is good for teeth if it continues too long, but a dummy has one big advantage: you can take it away. A thumb is always available. If your baby uses a dummy:
- choose an orthodontic shape and the right size for their age
- never dip it in honey, juice or anything sweet, which causes severe decay
- do not clean it in your own mouth, as that passes on decay-causing bacteria
- replace it when it shows signs of wear
- aim to phase it out between the ages of two and three, starting by limiting it to sleep times
4. Gentle Ways to Help a Child Stop
- Work out the triggers. Tiredness, boredom, anxiety and screen time are the usual ones. Offer a cuddle, a comfort toy or something to keep hands busy.
- Praise, do not punish. Nagging and shaming raise anxiety, and anxiety drives the habit.
- Use a reward chart with small, quick rewards for thumb-free periods, building up to whole days and nights.
- Make them a partner in the plan. Children over four often want to stop but do it without noticing. Agree on a quiet reminder signal.
- For night-time, a sock or glove over the hand, or a plaster on the thumb, can work as a reminder the child has agreed to.
- Pick a calm time. Not the week a new sibling arrives or school starts.
5. When to See the Dentist
Mention the habit at your child’s regular check-ups so that we can keep an eye on the bite. Book a visit specifically if the habit is still strong at four or five, if you can see a gap between the front teeth when your child bites together, or if the front teeth are starting to stick out.
A calm, friendly chat with the dentist about why it is time to stop often works better than months of reminders from Mum and Dad. For persistent habits past the age of six or seven, a simple dental appliance or a referral to an orthodontist may be recommended.
6. Will the Teeth Fix Themselves?
Very often, yes. If the habit stops before the adult front teeth come through, an open bite usually closes over the following months. The later it stops, the less the teeth self-correct and the more likely orthodontic treatment becomes. That is the real argument for acting at four or five rather than waiting. Our baby teeth timeline shows when those adult teeth are due.
Not Sure If It Is Affecting Their Teeth?
Bring your child in and we will take a look. Dr Liza Mekhael has a special focus on children’s dentistry, and Star Light Dental is a CDBS provider. Call (02) 9432 2833 or book online. We are open Saturdays from 10am to 3pm.