Mouth Breathing | Functional Growth

Mouth breathing in children can seem harmless at first, especially during colds or seasonal allergies. However, when mouth breathing becomes a daily habit (especially during sleep), it may be a sign of airway obstruction or functional growth concerns that can affect your child’s sleep, jaw development, and oral health. At San Marcos Pediatric Dentistry, we help families understand the cause of mouth breathing and what steps can support healthier breathing and proper development.

Is Mouth Breathing a Cause for Concern?

Occasional mouth breathing is common when a child is congested. But persistent mouth breathing, especially when your child is not sick, can be linked to underlying airway or structural issues. Over time, this habit may affect how the jaw grows, how the bite develops, and how well your child sleeps.

My Baby Sleeps With Their Mouth Open. Should I Be Worried?

In many cases, babies sleep with their mouths open due to temporary congestion. However, if your baby frequently sleeps with an open mouth and it continues long-term, it may be accompanied by signs such as:

• Irritability
• Cracked lips
• Excessive crying (especially in younger children)

If this pattern is consistent, it is a good idea to ask about it during your child’s dental visit.

What Dental Problems Can Mouth Breathing Cause?

Chronic mouth breathing can change the oral environment by drying out the mouth and reducing saliva, which plays an important protective role. Over time, mouth breathing may be associated with:

• Enlarged tonsils
• Enlarged adenoids
• Teeth grinding
• Temporomandibular disorder (TMD)
• Myofascial pain
• Periodontal disease
• Impacted teeth
• Malocclusion
• Tooth decay
• Chronic bad breath

Dry mouth can also increase the risk of cavities, especially when combined with snacking or poor brushing habits.

Can Mouth Breathing Affect Sleep and Overall Health?

Yes. Mouth breathing often happens during sleep and may signal reduced airflow through the nose. When breathing is disrupted at night, children may not reach deep, restorative sleep, which can affect daily functioning.

Common related concerns include:

• Daytime drowsiness
• Headaches
• Restless sleep
• Poor focus
• Memory issues
• Snoring
• Sleep deprivation

Healthy breathing supports healthy sleep, and healthy sleep supports healthy growth.

Why Is My Child Breathing Through Their Mouth?

Mouth breathing is often caused by nasal blockage or airway restriction. Some common causes include:

• Deviated septum
• Enlarged nasal vessels, bones, or tissue
• Tongue tie

In other cases, mouth breathing may be related to bite or jaw structure concerns. For toddlers who breathe normally during the day but sleep with their mouth open, the issue may involve the upper airway in the throat or nose.

How Can Mouth Breathing in Children Be Remedied?

Treatment depends on the cause, but the first step is evaluation. A care plan may include:

• Scheduling an assessment to evaluate airway and development concerns
• Considering adenoid or tonsil evaluation if needed
• Checking for nasal obstruction, allergies, sinus issues, or tongue tie
• Supporting a healthy weight, since excess weight can worsen breathing concerns

Early evaluation can help prevent long-term complications related to sleep and growth.

Can Mouth Breathing Cause Behavior Problems?

Yes. If mouth breathing leads to disrupted sleep or reduced oxygen intake during rest, it can affect behavior and learning. Some children may experience:

• Irritability
• Short attention span
• Difficulty concentrating
• Slower cognitive development
• Social and emotional challenges

When sleep improves, many families notice improvements in daytime mood and performance.

When Can Babies Breathe Through Their Mouths?

Babies may begin mouth breathing as early as three to four months, since they have not fully developed consistent nasal breathing patterns. If mouth breathing becomes persistent, it can continue into childhood and may affect development if not addressed.

How Do You Treat Mouth Breathing in Children?

Once the cause is identified, treatment may involve one or more approaches such as:

• Allergy management
• Breathing training
• Surgical care (tonsil or adenoid removal when recommended)
• Habit correction strategies (such as thumb-sucking support)
• Orthodontic or growth guidance interventions

The right approach depends on what is causing the airway restriction.

Can Mouth Breathing Affect a Toddler’s Speech?

Yes. Long-term mouth breathing may influence tongue posture and swallowing patterns. This can contribute to:

• Difficulty with certain sounds
• Lisp development
• Tongue thrust swallowing pattern

In some cases, this may also increase difficulty swallowing or increase the risk of choking.