How Facial and Oral Muscles Affect Your Child’s Smile

The position and alignment of teeth and jaws are not determined by bones and genetics alone. The muscles of the face, jaw, tongue, and throat — and the patterns of how those muscles function at rest and during activities like swallowing, speaking, and breathing — play a significant role in shaping how the dental and skeletal structures develop, and in determining whether orthodontic treatment results remain stable over time.

When those muscle patterns are abnormal — a condition known as orofacial myofunctional disorder (OMD) — they can actively work against orthodontic treatment, contributing to relapse, perpetuating habits that undermine jaw development, and in some cases causing problems that braces alone cannot fully resolve.

At Cranston Orthodontics, Dr. Cosmo incorporates myofascial and orofacial myofunctional assessment into the comprehensive diagnostic evaluation for pediatric patients — identifying muscle function issues early and coordinating with qualified therapists to address them as part of a truly integrated treatment plan.

What is Orofacial Myofunctional Disorder

An orofacial myofunctional disorder (OMD) refers to abnormal patterns of muscle function involving the face, mouth, tongue, and throat. The most common OMDs seen in orthodontic patients include:

Tongue Thrust

A tongue thrust occurs when the tongue pushes forward against or between the teeth during swallowing, speaking, or at rest — rather than resting against the palate. Persistent tongue thrust exerts forward pressure on the front teeth, contributing to open bites, overjet, and instability after orthodontic treatment.

Low Tongue Posture

The tongue should rest comfortably against the palate when the mouth is at rest. When the tongue rests low — on the floor of the mouth or against the lower teeth — it fails to provide the natural internal pressure that supports proper upper arch development, contributing to narrow arches and the airway concerns described on our Airway & Breathing Evaluation page.

Abnormal Swallowing Patterns

In a mature swallowing pattern, the tongue presses against the palate and the lips seal lightly. In an infantile or reverse swallow — which some children retain beyond the appropriate developmental stage — the tongue pushes forward against the teeth and the facial muscles contract visibly. This pattern places continuous abnormal force on the teeth and jaw.

Lip Incompetence

When the lips cannot meet comfortably at rest without straining, it often indicates abnormal muscle tone or jaw positioning. Chronic lip incompetence is associated with mouth breathing, increased overjet, and long-term dental instability.

Oral Habits

Persistent thumb-sucking, finger-sucking, nail-biting, and lip or cheek biting beyond the appropriate developmental age are considered orofacial myofunctional habits. These habits alter the forces acting on the developing jaw and teeth, contributing to characteristic orthodontic problems — including anterior open bites, increased overjet, and asymmetrical arch development.

How OMDs Affect Orthodontic Treatment

An orthodontic appliance can move teeth into proper alignment — but it cannot change the muscle patterns that act on those teeth every day. If the underlying myofunctional disorder is not addressed, the same forces that contributed to the original problem will continue to act on the teeth after treatment is complete — contributing to relapse and instability.

Research consistently shows that patients with untreated tongue thrust and other orofacial myofunctional disorders are at significantly higher risk of orthodontic relapse — particularly in the anterior region. Addressing these patterns before, during, or immediately after orthodontic treatment is one of the most effective ways to protect the stability of the orthodontic result.

Beyond stability, untreated OMDs can also limit what orthodontic treatment alone is able to achieve. An open bite maintained by persistent tongue thrust, for example, may resist closure during treatment or reopen after treatment ends — unless the muscle pattern driving it is corrected.

How Cranston Orthodontics Addresses Myofascial and Myofunctional Concerns

Assessment: Myofunctional assessment is integrated into Dr. Cosmo's comprehensive diagnostic evaluation for pediatric patients. He evaluates tongue posture and function, swallowing pattern, lip seal and tone, facial muscle activity, and the presence of oral habits — building a complete picture of how the muscles of the face and mouth are functioning and how that function is affecting the developing dentition.
Coordination with orofacial myofunctional therapists: Where myofunctional therapy is indicated, Dr. Cosmo coordinates a referral to a qualified orofacial myofunctional therapist (OMT) — a specialist trained to retrain the muscles of the face, mouth, and throat through structured therapeutic exercises. Orofacial myofunctional therapy is an evidence-based approach that has been shown to significantly improve tongue posture, swallowing pattern, and nasal breathing in children and adults.
Integration with orthodontic treatment: Myofunctional therapy is planned in coordination with the orthodontic treatment timeline — ensuring that muscle retraining and orthodontic tooth movement are working together, not against each other. Dr. Cosmo maintains ongoing communication with the treating therapist throughout the process.
Habit appliances: For children with persistent oral habits that have not responded to behavioral intervention, Dr. Cosmo may recommend a habit appliance — a device designed to interrupt the habit pattern and allow the jaw and teeth to develop without the distorting force of the habit. Habit appliances are used judiciously and always as part of a broader treatment plan.

Signs Your Child May Benefit From Myofunctional Assessment

Mouth breathing at rest or during sleep
Tongue pushing against or between the teeth during swallowing or at rest
An open bite — a space between the upper and lower front teeth when the mouth is closed
Protruding front teeth with no clear skeletal explanation
Persistent thumb or finger-sucking past age 4
Difficulty producing certain speech sounds (particularly s, z, sh, ch, j)
Visible strain in the facial muscles when swallowing
Relapse of orthodontic treatment after a previous course of treatment
Low tongue posture observed at rest

Ask Dr. Cosmo About Myofascial Assessment at Your Child's Evaluation

Myofunctional assessment is part of the comprehensive diagnostic approach at Cranston Orthodontics. Schedule your child's complimentary new patient exam today — and find out whether myofascial therapy should be part of their treatment plan.

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Frequently Asked Questions

An orofacial myofunctional disorder refers to abnormal patterns of muscle function involving the face, mouth, tongue, and throat. The most common forms seen in orthodontic patients are tongue thrust — where the tongue pushes forward against the teeth during swallowing or at rest — low tongue posture, abnormal swallowing patterns, lip incompetence, and persistent oral habits like thumb-sucking. These disorders are more common than most parents realize, and because they often produce no obvious symptoms, they frequently go undetected until they begin interfering with orthodontic treatment.

The muscles of the face, tongue, and throat exert continuous force on the teeth and jaw — far more consistently than any orthodontic appliance does. When those muscle patterns are abnormal, they actively shape how the jaw and teeth develop. A tongue that rests low instead of against the palate, for example, deprives the upper arch of the natural internal pressure it needs to develop properly width. A tongue that thrusts forward during every swallow places ongoing outward pressure on the front teeth. Over time, these forces produce characteristic bite problems and arch deformities that braces alone may struggle to fully correct.

Braces move teeth into the correct position — but they cannot change the muscle patterns that act on those teeth thousands of times per day through swallowing, breathing, and resting posture. If the underlying myofunctional disorder is not corrected, the same forces that caused the original problem will continue to act on the teeth after treatment ends. Research consistently shows that patients with untreated tongue thrust and related OMDs are at significantly higher risk of orthodontic relapse, particularly in the front teeth. Addressing muscle patterns is one of the most important things a patient can do to protect the long-term stability of their orthodontic result.

Orofacial myofunctional therapy (OMT) is an evidence-based therapeutic approach that retrains the muscles of the face, mouth, and throat through structured exercises. A qualified orofacial myofunctional therapist works with patients to correct tongue posture and resting position, establish a mature nasal swallowing pattern, improve lip seal and tone, and eliminate oral habits. Therapy is typically conducted over a series of sessions and includes home exercises to reinforce the new muscle patterns between appointments.

Dr. Cosmo identifies myofunctional concerns as part of his comprehensive diagnostic evaluation and coordinates referrals to qualified orofacial myofunctional therapists for patients who need them. He maintains ongoing communication with the treating therapist throughout the process to ensure that muscle retraining and orthodontic tooth movement are progressing in coordination — working together rather than against each other.

The earlier, the better. Myofunctional disorders identified during active jaw growth are most responsive to treatment, and addressing them early protects the developing dentition from the ongoing distorting forces of abnormal muscle patterns. That said, orofacial myofunctional therapy is effective in older children, teenagers, and adults as well — and is particularly important before, during, or immediately after orthodontic treatment at any age.

Quite possibly. Orthodontic relapse — especially in the front teeth — that occurs despite consistent retainer wear is one of the strongest indicators that an underlying myofunctional disorder was never addressed. A persistent tongue thrust or abnormal swallowing pattern can gradually displace teeth even against the resistance of a retainer, particularly a removable one. If your child experienced relapse after prior orthodontic treatment, a myofunctional assessment as part of a new evaluation at Cranston Orthodontics is strongly recommended.

Key signs include mouth breathing at rest or during sleep, the tongue visibly pushing against or between the teeth during swallowing, an open bite between the upper and lower front teeth when the mouth is closed, noticeably protruding front teeth without a clear skeletal explanation, persistent thumb or finger-sucking past age 4, difficulty producing certain speech sounds — particularly s, z, sh, ch, or j — visible straining of the facial muscles when swallowing, and prior orthodontic relapse. Any of these warrants a conversation with Dr. Cosmo at your child's evaluation.