Short answer: Long-term mouth breathing is associated in some children of growing age with a narrow upper jaw, a high palate, crossbite and crowded teeth, but it does not have the same effect in every child. The cause is most often enlarged adenoids, allergies or nasal congestion, and it should be evaluated by an ENT specialist. The orthodontist monitors jaw development and, if needed, plans options such as expansion during the growth period.
If you have noticed that your child sleeps with their mouth open at night and that their lips are often apart during the day, it is quite natural to wonder whether this is only a habit or a sign that needs attention. Mouth breathing is a condition associated with jaw and tooth development, especially in children of growing age. In this article, we explain in a calm and realistic way which signs to look out for, which doctors take part in investigating the cause and where orthodontics stands in this process.
Does mouth breathing affect jaw development?
Long-term mouth breathing that has become a habit can affect jaw development in some children, but it does not lead to the same outcome in every child. Normally, when breathing through the nose, the tongue rests against the palate and the lips stay closed. This position of the tongue acts as a natural support for the widening of the upper jaw. When the mouth stays open all the time, the tongue sits lower, the cheek muscles press on the upper jaw without support from the inside, and this balance can change.
Studies show that there can be a relationship between chronic mouth breathing and a narrow upper jaw, a high palate, crossbite and lengthening of the face in the vertical direction. That said, facial and jaw development also depends on genetic makeup, eating habits and many other factors. For this reason, it is not right to say that "mouth breathing definitely disrupts jaw development"; the more accurate statement is that long-term mouth breathing should be considered as a risk factor.
Signs to watch for in children
The clearest sign that suggests mouth breathing in children is the lips staying open all the time, both during the day and in sleep. Other signs that parents may notice are as follows:
- The child sleeps with their mouth open, snores often or seems to sleep restlessly
- Dry mouth in the mornings, cracked lips or bad breath
- Tiredness during the day, distractibility or restlessness
- Constant nasal congestion, frequently recurring colds or a runny nose
- Chewing with the mouth open while eating and getting out of breath
- The upper front teeth tilting forward or the teeth being arranged in a narrow arch
Seeing one or several of these signs does not by itself mean there is a problem. However, mouth breathing that lasts for several weeks, especially when it is more marked during sleep, is reason enough to consult a doctor. Instead of trying to make a diagnosis at home based on these signs, having the cause investigated by a specialist is the healthiest path.
Adenoids, allergies and nasal congestion
The most common causes of mouth breathing in children are conditions that narrow the nasal passage. These include enlarged adenoids, large tonsils, allergic rhinitis, swelling of the structures inside the nose or a deviation in the nasal septum. In some children, mouth breathing can continue as a habit even after the initial congestion has passed.
The appearance referred to in the literature as "adenoid face" is a face type described in children with long-term mouth breathing: lips that stay apart, a lower face that looks long, narrow nostrils and a narrow upper jaw are among the features listed in this picture. Still, this is a description, not a diagnosis. It is not possible to decide that a child has enlarged adenoids by looking at their facial structure.
Evaluating the nasal and adenoid passage is the field of the Ear, Nose and Throat (ENT) specialist. When the orthodontist notices dental and jaw findings that suggest mouth breathing, they refer the family to an ENT evaluation. Orthodontic interventions done before the cause in the airway has been removed may not give the expected result in the long term.
A narrow upper jaw and crossbite
The most common finding at the orthodontic exam in children with mouth breathing is a narrow upper jaw and a resulting crossbite. When the upper jaw has not widened enough, the upper teeth may sit inside the lower teeth rather than outside them. This can be seen on one or both sides and sometimes causes the lower jaw to slide to one side as it closes.
A narrow palate also reduces the space in which the teeth will be arranged. During the transition from baby teeth to permanent teeth, a lack of space can become marked and the permanent teeth may come in crowded. The upper front teeth tilting forward can keep the cycle going by making it harder for the lips to close.
In children of growing age, because the growth zone at the midline of the upper jaw has not yet closed, expansion treatments done in this period generally respond better. We described in detail how these treatments are applied on our page on jaw expansion treatment.
Which doctors evaluate it together?
Evaluating a child who breathes through the mouth generally requires cooperation between more than one doctor. Each specialty looks at a different part of the picture:
- Pediatrician: Makes the first evaluation in terms of general health, growth and frequently recurring infections.
- ENT specialist: Examines the nose, adenoids and tonsils; investigates the cause of blockage in the airway and plans treatment if needed.
- Allergy specialist: If allergic rhinitis is suspected, carries out the relevant tests and follow-up.
- Orthodontist: Evaluates the development of the jaws, the width of the palate, the bite and the alignment of the teeth.
The order matters in this cooperation. In most cases, the openness of the airway is evaluated first and the orthodontic need is addressed afterward. When our clinic sees a finding that suggests mouth breathing, we refer the family to an ENT evaluation; any medication or treatment recommendation is the decision of the relevant specialist.
What are the orthodontic options?
Orthodontic options are determined according to the child's age, the stage of jaw development and the exam findings. In general, the following approaches may come into question:
- Early monitoring: If there is no marked problem, the child's development is followed at certain intervals.
- Upper jaw expansion: For a narrow palate and crossbite, expansion appliances applied during the growth period may be used.
- Functional appliances: Appliances that help guide the position of the jaws relative to each other may be preferred in some cases.
- Habit training: After the airway has been opened, guidance can be given for lip closure and correct tongue position; if needed, work is done together with the relevant therapists.
The aim of these treatments is to use growth potential in the right direction. For more information on when early intervention is needed and when it can wait, you can read our page on early orthodontic treatment. In suitable cases, Invisalign First is also among the options that can be considered for young children; suitability is determined at the exam.
It is also necessary to be careful about the exercises and tongue-positioning techniques often seen online. The effect of these methods on jaw structure is limited, and they do not remove a blockage in the airway. We covered this topic separately in our article on what mewing is and whether the jawline changes.
Pediatric orthodontics in Ankara
The Turkish Orthodontic Society and the American Association of Orthodontists recommend that a child's first orthodontic check-up be done around age 7; this age is a suitable time for problems in jaw development to be noticed early. We explained the reasons in our article on the first orthodontic exam in children. If you have noticed that your child sleeps with their mouth open or that their teeth are arranged in a narrow arch, at our clinic in Oran, Çankaya, we can evaluate jaw and tooth development and, if needed, talk through a follow-up plan to proceed together with an ENT specialist.
Frequently asked questions
My child sleeps with their mouth open; does this definitely mean adenoids?
No. Sleeping with the mouth open can be seen for different reasons besides adenoids, such as allergies, nasal congestion, large tonsils or habit. An ENT specialist's evaluation is needed to determine the cause.
Does a narrow jaw caused by mouth breathing correct itself?
After the airway is opened, development may proceed in a more balanced way in some children, but a crossbite that has formed or a marked narrowing of the palate generally does not correct itself. Orthodontic follow-up helps determine whether intervention is needed and its timing.
Should I go to the orthodontist first or to an ENT specialist?
If there is marked nasal congestion, snoring or restless sleep, the priority is in most cases an ENT evaluation. If you have noticed a problem in the teeth or the bite, an orthodontic exam can also be done; the two evaluations complement each other.
At what age is orthodontic treatment started in children who breathe through the mouth?
The first orthodontic check-up is generally recommended around age 7. Whether treatment is needed and when to start are determined by the dentist according to the child's jaw development and the exam findings.
