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When Should My Child Stop Using a Pacifier or Sucking Their Thumb?

From your family dentist: A parent’s guide to the research on non-nutritive sucking habits, dental development, and when to get your child checked.

Most parents don’t lose sleep over thumb-sucking in a newborn. But they do ask me, a lot: when does it become a real problem? Should I be doing something about it? The tricky part is that these changes don’t cause pain or any visible signs early on, so they can go unnoticed until they’re harder to correct.

If you’re based in St. Clair West, Corso Italia, or the surrounding area and you’re wondering whether it’s time to have your child’s teeth looked at, this is a good place to start. We’ve gone through the research, including the Cochrane review that specifically looked at these habits, and the picture is actually clearer than most people expect.

At our St. Clair West practice, we see families with questions exactly like this all the time. If you’d rather just book and have someone take a look, you can request an appointment here.

The habit itself is completely normal

Sucking is one of the first things babies do. It’s instinctive, it’s comforting, and for very young infants it carries some genuine benefits. Pacifiers in particular have good evidence behind them for reducing the risk of SIDS and providing pain relief during minor procedures. There’s also a Cochrane review that found pacifier use doesn’t meaningfully affect breastfeeding in healthy term infants, which is a common worry among new parents.

So there’s no reason to rush to remove a pacifier from a 6-month-old. The concern is really about what happens if the habit continues well past that early stage.

What prolonged sucking can do to teeth

The mouth is actively developing throughout early childhood, and sustained pressure from sucking causes changes over time. The main issues we often see are:

  1. An anterior open bite (where the front teeth don’t touch when the mouth is closed)
  2. A posterior crossbite (where the back teeth don’t line up properly)
  3. A wider than normal gap between the upper and lower front teeth
  4. Narrowing of the upper arch

How much change occurs depends on how long the habit goes on, how many hours a day it happens, and how intense the sucking is. Pacifiers and thumb sucking tend to cause slightly different problems.

Prolonged sucking habits that alter the bite or jaw structure can also contribute to longer-term jaw alignment issues.

The pacifier teeth effects are mainly crossbite and open bite. Thumb sucking tends to push the upper front teeth forward more. Here’s the link if you want to read more.

When does it actually become a problem?

This is what everyone wants to know. Most changes in the baby teeth will resolve on their own if the habit stops early enough. The mouth has a decent ability to recover, particularly for open bites. But that window does close.

Research points to around age 3 to 4 as the point where things shift from “likely to resolve on its own” to “may need treatment down the line.” A longitudinal study tracking children from birth found that habits continuing to 48 months or beyond produced the most significant changes to the dental arch and bite. Even children who stopped a bit before that still showed some differences compared to those who stopped early.

Age What’s happening What to do
0–12 months Sucking reflex is strongest. Pacifiers carry real benefits — SIDS reduction, pain relief, no breastfeeding impact. Nothing needed.
12–24 months Good time to start winding down pacifier use. Stopping cold turkey before 14 months can trigger finger sucking instead. Gradually reduce pacifier use. Aim to phase out by 18 months.
Ages 2–3 Most children stop thumb sucking on their own in this window. If a pacifier is still going strong, be more intentional about winding it down.
Ages 3–4 Critical window. Habits continuing past 48 months produce the most lasting changes to the bite and arch. Act now — not just monitor.
Beyond age 4 Associated with open bite, Class II jaw relationship, and pronounced forward movement of upper front teeth. Get the teeth checked. Some changes need orthodontic treatment.

Is your child 3 or older and still using a pacifier or sucking their thumb? It’s worth having their teeth checked sooner rather than later. Book a children’s dental appointment at Tinto Dentistry here and we’ll take a look together.

Pacifier or thumb: which is worse?

The general view in the literature is that pacifiers are the lesser concern, mainly because you can take them away. A thumb is always there. Some clinicians actually suggest switching a thumb-sucking infant to a pacifier for this reason, since it gives parents more control over when the habit ends.

That said, a longitudinal study of 372 children found that some changes to the dental arch persisted well after the habit stopped, whether it was a pacifier or a finger sucking habit. The “it’ll all sort itself out” assumption doesn’t always hold, which is part of why regular monitoring from a young age matters.

Does it self-correct after stopping?

Sometimes, yes. Anterior open bite in particular shows a reasonable rate of self-correction after the habit stops, especially in the baby teeth stage. Some crossbites also improve on their own.

But “some children self-correct” isn’t the same as “most children self-correct.” Posterior crossbite tends to be more persistent. And once the permanent teeth start coming through around age 6, the window for things to settle on their own closes considerably.

What actually helps children stop?

The 2015 Cochrane review looked at this directly and found that both orthodontic appliances and behavioural interventions work better than doing nothing. Options range from least to most intensive:

Positive reinforcement — the natural starting point. Reward charts, praise, and making a low-key fuss of small wins work for a lot of children. The American Academy of Pediatric Dentistry specifically recommends this over criticism or pressure, which can backfire and make the habit stick around longer.
Bitter-tasting products applied to the thumb or fingers are a low-cost option that don’t require any clinical input. They need consistent use to be effective.
Physical barriers such as thumb guards or mittens at night can help with overnight habits particularly.
Orthodontic habit-breaking appliances are fitted by a dentist and work by making sucking physically unrewarding. The Cochrane review found that a palatal crib was significantly more effective than a simpler palatal arch. Reserved for cases where other approaches haven’t worked or where there is already some dental change that needs addressing.

One thing is consistent across the research: scolding, criticism, and making children feel bad about the habit tends to make things worse, not better.

Not sure which approach fits your child? Come in for a chat and we can talk through the options together.

The short version

If your child is under 2 and still on a dummy or sucking their thumb, there is no emergency. If they’re approaching 3 and the habit is very much still present, it’s worth starting to work on it gently. If they’re hitting 4 and nothing has changed, getting their teeth looked at is the right move. Not because things are necessarily damaged, but because earlier is always easier.

The research is pretty clear: the sooner the habit stops, the better the odds that nothing permanent comes of it. And if you’re unsure, a quick check is the most straightforward way to get an honest answer.

We’re based on St. Clair West near Corso Italia and we love seeing little ones. Book your child’s appointment here or drop us a message if you’d like to ask us anything first.

Frequently Asked Questions

When should my child stop using a pacifier?

The ideal time to start winding down pacifier use is around 12 months, with the goal of phasing it out by 18 months. Most children can manage this transition gradually with a bit of encouragement. If the pacifier is still going strong at age 3, it is worth being more proactive, because past that point the risk of open bite and crossbite rises noticeably and keeps rising the longer the habit continues. One small thing to keep in mind: stopping the pacifier abruptly before 14 months has been linked to children switching to finger sucking instead, so a gradual wind-down works better than going cold turkey very early.

Is thumb sucking worse than a pacifier?

In some ways, yes. The main reason pacifiers are considered the lesser concern is that you can take them away. A thumb is always available, which means the habit tends to last longer and accumulate more hours of pressure overall. Thumb sucking also tends to push the upper front teeth forward more than a pacifier does, creating a larger gap between the upper and lower teeth. That said, pacifiers are more strongly associated with posterior crossbite and narrowing of the upper arch. So they cause different problems rather than one being universally worse than the other. What really matters is how long the habit goes on.

Will my child’s teeth fix themselves after the habit stops?

Sometimes, and it depends a lot on when the habit stopped and what kind of change has occurred. Anterior open bite has a reasonable rate of self-correction in the baby teeth stage once the sucking pressure is gone. Some crossbites also improve on their own. The less encouraging news is that posterior crossbite and arch width changes tend to be more stubborn, and a longitudinal study of 372 children found that some changes persisted well after the habit had stopped. Self-correction becomes less likely the longer the habit ran, and once the permanent teeth start coming through around age 6, the window for things to settle naturally closes considerably.

When should I see a dentist about this?

If your child is under 2, there is no urgency. If they are approaching 3 and the habit is still very much present, it is a good time to mention it at their next dental visit so the teeth can be monitored. If they are reaching age 4 and nothing has changed despite your best efforts, booking an appointment specifically to discuss it is the right call. A dentist for children can give you an honest picture of whether things are on track or whether some support would help. It is a much easier conversation at 4 than at 10. If you are based in St. Clair West or Corso Italia and you would like someone to take a look, we would be happy to help. Book here or send us a message if you have questions first.

References

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