Thumb Sucking & Pacifiers: When Does It Become a Problem?

← Back to All Articles

It Starts as a Reflex — and That's Completely Normal

Babies are born with a strong sucking reflex — it's how they feed and how they self-soothe. Sucking a digit or a pacifier satisfies what's called a non-nutritive sucking need, and in infants and young toddlers it is developmentally normal and often actively beneficial. The concern comes not with the habit itself, but with how long it continues past the point when teeth and jaw bones are actively developing.

At Little Smiles Children's Dentistry, we discuss oral habits at every checkup for families at our St. Augustine pediatric dental office and our Palm Coast location. Here is the full picture — benefits, risks, and what the evidence actually says.

The Real Benefits of Pacifier Use in Early Infancy

Pacifiers are not just a convenience for parents — they carry genuine health benefits in the early months of life that are recognized by both the American Academy of Pediatrics (AAP) and the American Academy of Pediatric Dentistry (AAPD):

• SIDS reduction: The AAP recommends offering a pacifier when placing an infant to sleep because of its protective effect against sudden infant death syndrome (SIDS). This recommendation is supported by the Safe to Sleep Campaign of the US Department of Health and Human Services.
• Pain relief: Pacifiers provide a documented analgesic effect during minor procedures in newborns and infants — heel sticks, blood draws, and similar common procedures.
• Self-soothing and stress reduction: The controlled action of sucking promotes feelings of security and helps infants manage stress, including in neonatal intensive care environments.
• Reduces the risk of thumb sucking: Children who begin using an orthodontic pacifier before 4 months of age have a lower risk of developing a persistent finger or thumb habit compared to children who start after 4 months. Forced early cessation of pacifier use has actually been associated with prolonged finger sucking.
• Supports premature infants: Early oral stimulation from a pacifier helps premature infants develop and maintain the sucking reflex needed for feeding.

The AAPD policy is clear: pacifiers are appropriate and beneficial during the first few months of life. The goal is not to avoid pacifiers — it is to wean from them at the right time.

The AAPD Timeline: When the Risk Starts to Build

According to the AAPD's 2024 Policy on Pacifiers, the concern about dental impact follows a clear progression based on age:

• After 12 months: Pacifier use increases the risk of acute otitis media (ear infections). The incidence of ear infections may be reduced by decreasing or eliminating pacifier use in the second six months of life.
• Around 18 months (canine emergence): The AAPD recommends beginning to discontinue or limit pacifier use around the time the canine teeth emerge — approximately 18 months — to limit the development of posterior crossbite. Beyond 18 months, pacifier use begins to influence the developing orofacial complex.
• By 36 months: This is the AAPD's key target. The AAPD encourages discontinuance of nonnutritive sucking habits by 36 months of age. Children who use a pacifier for 36 months or longer have a significantly higher incidence of anterior open bite. Importantly, an anterior open bite that develops from pacifier use will improve after elimination of the pacifier before age 3.
• Beyond 36 months: The percentage of open bite increases significantly the longer the habit continues past 3 years of age. The transverse occlusal relationship (crossbite risk) should be evaluated before age 3. Research shows that malocclusion is affected by duration of the habit more than frequency.

What Prolonged Habits Actually Do to Teeth and Jaws

The degree of dental change depends on the intensity and duration of the habit. Passive resting of a thumb or pacifier in the mouth creates less pressure on developing structures than vigorous sucking. According to the AAPD, duration of the habit matters more than frequency. Common effects of prolonged nonnutritive sucking include:

• Anterior open bite — the upper and lower front teeth don't make contact when the back teeth are together, leaving a gap in the front of the mouth
• Posterior crossbite — the upper jaw becomes constricted, causing lower back teeth to close outside of the upper teeth; can include midline deviation
• Increased overjet — upper front teeth are pushed forward ("buck teeth"); this is more strongly associated with finger habits than with pacifier habits
• Class II malocclusion — also more strongly linked to finger and thumb habits than pacifier use, per AAPD
• Speech effects — an open bite can contribute to a lisp or difficulty producing certain sounds, though evidence linking pacifier use specifically to speech delay is limited

Pacifier vs. Thumb Sucking — Which Is Worse?

Both habits can produce open bite and crossbite, but there are meaningful differences. According to the AAPD, increased overjet and Class II malocclusion are more strongly associated with finger habits than with pacifier habits. In other words, prolonged thumb sucking carries a higher risk of the more serious bite problems.

The most significant practical difference, however, is control: you can take away a pacifier. You cannot take away a thumb. Pacifier weaning gives parents more agency over timing — gradual reduction, limiting to sleep only, or a "pacifier fairy" exchange can all work well between ages 2 and 3. Thumb sucking in an older child who has developed a strong emotional attachment to the habit is considerably harder to address.

Does Pacifier Type Matter?

Yes — to a degree. A systematic review cited in the AAPD policy found that orthodontic pacifiers induce less open bite compared to conventional pacifiers. However, two separate reviews concluded that the evidence is not sufficient to fully support orthodontic pacifiers as a prevention strategy for malocclusion. The most important factor remains when the habit ends.

Pacifier sizing has also come into focus in recent research. Proper fit is important for providing palatal support and preventing loss of transverse palatal dimensions — undersized pacifiers may contribute to palatal collapse and early posterior crossbite development.

A few safety reminders from the AAPD and AAP:

• Choose a one-piece pacifier — less likely to break apart and become a choking hazard
• The shield should be firm, have ventilation holes, and measure at least 1.5 inches across so it cannot pass completely into the mouth
• Inspect the pacifier regularly for structural wear and replace if damaged
• Never dip a pacifier in honey — honey contains spores of Clostridium botulinum, which can cause infant botulism, respiratory failure, and death. The FDA has issued explicit warnings on this
• Sterilize regularly by boiling in water for 15 minutes or spraying with an antimicrobial agent to minimize bacterial and yeast contamination

Strategies That Actually Work for Weaning

The AAPD notes that positive reinforcement is preferable to negative reinforcement when working on habit cessation. Criticism, restraint, or punishment can create power struggles that actually extend how long the habit lasts. The goal is to make stopping feel like an achievement, not a loss.

For toddlers weaning from a pacifier (target: by 36 months):

• Begin limiting pacifier use to sleep times only around 18 months, then gradually eliminate it there too before age 3
• The "pacifier fairy" — child gives away their pacifiers in exchange for a small gift or experience; works well around age 2.5–3
• Reduce access rather than force removal — put pacifiers out of sight during the day
• Praise and acknowledge each day the child self-soothes without it; a simple sticker chart works well for toddlers

For older children with thumb sucking (ages 4+):

• Wait until the child is motivated — forcing a child who isn't ready rarely works
• Identify triggers (tired, anxious, bored) and offer replacement strategies for those moments
• A bandage or light glove on the thumb as a physical reminder — not a punishment, framed as a helpful tool the child controls
• Use a sticker chart for thumb-free days with a meaningful reward at milestones
• Ask your dentist to speak directly with the child — children often respond differently to hearing feedback from someone other than a parent

Will the Teeth Fix Themselves After Stopping?

Often, yes — and the AAPD is specific about this: an anterior open bite caused by pacifier use will improve after the pacifier is eliminated before age 3. This is one of the strongest reasons the 36-month target matters. Once the habit stops and the pressure on the jaw is removed, the bones — which are still highly malleable at this age — often self-correct as permanent teeth begin to come in.

The window for natural correction narrows after age 3, and changes that are still present once the permanent teeth are established (around age 12–13) are unlikely to resolve without orthodontic treatment. Stopping the habit early is not just about the primary teeth your child has right now — it's about setting the trajectory for the permanent ones.

Source: American Academy of Pediatric Dentistry. Policy on pacifiers. The Reference Manual of Pediatric Dentistry. Chicago, IL: AAPD; 2025:86–9. Revised 2024.