Orthodontic info
My child does not seem able to close their mouth all the way. Is that a problem?
Sometimes, yes: when a child cannot comfortably keep the lips together with the mouth closed and at rest, the American Association of Orthodontists (AAO) calls the condition lip incompetence and says it can affect facial muscles, which could alter facial development.
On this page
Why the lips may not meet over the teeth
Lip incompetence is usually due to protrusive front teeth or an excessively long face, according to the AAO glossary. The position of the lips is closely associated with the position of the underlying teeth, the AAO says, so teeth that are too protrusive may push the lips forward or even force them apart; for teeth that protrude, see when a child's front teeth stick out.
Facial imbalance is one of the AAO's warning signs for growing children: the underlying teeth and jaws, the AAO says, may affect how the lips, the chin and the rest of the face look.
Mouth breathing is another of the AAO's warning signs for growing children, and the AAO says many orthodontic problems can develop as a result of mouth breathing; the practice's airway orthodontics page focuses on how the mouth, jaw and airway work together, and it says braces alone are not a cure for sleep apnea.
How the exam sorts out the cause
An evaluation is the AAO's advice for lips that cannot comfortably close at rest, and at a first visit the AAO says the orthodontist evaluates the teeth, bite and jaws, and the office may take photos, X-rays or digital scans to help create a diagnosis. At Carvalho & Roth Orthodontics, the initial examination takes digital photos and X-rays, and the AAO notes that photographs of a child's teeth and face can be documentation referred to at later visits.
What follows the evaluation depends on the cause it finds, and the concerns for which the AAO's October 2026 article says an orthodontist "may recommend early treatment" are listed on the early orthodontic treatment page.
Notes worth taking at home
Watching at home gives the exam something to work with: note whether the lips stay apart when your child is relaxed, whether your child breathes through the mouth, and when you notice each. Recalling your child's dental history is part of preparing, according to the practice's first consultation page.
When to call about lips that stay apart
A call does not need to wait for a birthday: in an FAQ entry dated October 2026, the AAO recommends a child's first orthodontic check-up when a problem is first recognized and no later than age 7, and another entry in the same FAQ says a parent who notices something that appears "off" before then need not wait or get a recommendation from the dentist.
Questions
Frequently asked questions
Can lips that stay apart affect how my child's teeth come in?
Possibly. The AAO says that when a person cannot comfortably keep the lips together at rest, there may be problems with swallowing, jaw joint function and the way teeth come in, and it advises an evaluation by an orthodontist.
What does a relaxed, closed mouth usually look like?
The AAO's general answer, written for anyone rather than for children in particular, is that when the mouth is closed the lips should be relaxed, the jaw should not feel tight and the teeth should not be clenched. A child who cannot rest that way is worth describing at the exam.
Should my child practice holding the lips closed?
Ask the orthodontist first. The AAO says a person should not need to consciously use the facial muscles to close the lips over the teeth, so visible effort to keep them closed is a finding for the exam to explain, and the cause the exam finds decides what, if anything, helps.
Request a consultation
Tell us which office and who the visit is for, and we will call you back.