Orofacial Myofunctional Disorders

Orofacial Myofunctional Disorders are atypical, adaptive patterns that emerge in the absence of normalized patterns within the orofacial complex. The regular presence of these adaptive movements can often result in a variety of disturbances.  It is often difficult to isolate a particular source as the sole cause of an Orofacial Myofunctional Disorder and in most cases, it can be result of a combination of factors. Two major recognized factors are airway issues and or sucking habits.

An OMD disorder involves abnormal rest postures which either prevent or disrupt normal growth and development. When normal growth and development is disrupted due to an abnormal tongue rest posture, the dental freeway space is opened beyond the normal range, leading to changes in structure and functions.

The regular presence of these adaptive movements can often result in a variety of disturbances

Symptoms of Orofacial Myofunctional Disorders

• Open mouth rest posture of the lips

• Low rest posture of the tongue when the mandible is hinged open.

• Malocclusion

• Recurring malocclusion after dental intervention

• Weak obicularis oris

• Difficulty with solid foods-chewing, gathering, swallowing

• Thumb-finger-digit-tongue sucking problems

• Speech problems (interdental or lateral /s/ lisp, misarticulation of the /t/,/d/,/n/,/l/

• Facial grimace during swallow

• Ankylosed tongue

• High narrow arched hard palate

Tongue Thrust - Abnormal Tongue Pattern

Tongue thrusting is an adaptation to rather than a cause of tooth changes and malocclusion.  It is not the primary cause it is an adaptation, therefore, will be addressed with all abnormal tongue patterns. Two recognized etiologies contributing to abnormal tongue patterns are airway issues and sucking habits.  Thumb sucking anchors the tongue down and forward instead of allowing the tongue to rest in the proper position Increasing the freeway space dimension. Increasing the freeway space dimension contributes to abnormal tongue patterns, such as, low forward rest posture of the tongue, open mouth rest posture of the lips. Complications that can develop include disordered breathing, speech distortions, change in craniofacial development, changes in body posture, malocclusions.

Treatment of orofacial myofunctional disorders involves ‘Rest Posture Therapy’ which includes treatment of the open mouth rest posture of the lips, low forward rest posture of the tongue, tongue thrusting. Therapy involves normalizing the abnormal tongue functioning pattern as a way of stabilizing the freeway space.

Low Forward Rest Posture of the Tongue

Very light resting tongue pressures can influence tooth eruption and contribute to a malocclusion, the most common being open bite and excessive overjet. The forward rest posture of the tongue provides continuous and intermittent pressure; disrupting the dental equilibrium by opening the freeway space beyond its normal range. When the freeway space is open for hours a differential dental eruption can occur resulting in malocclusion.

Low Forward Rest Posture of the Tongue
This differential eruption and the force of the tongue resting forward is the primary mover of teeth rather than the actual tongue thrust, which is commonly thought to be the contributor. Possible causes of a low forward rest posture of the tongue include: thumb/finger sucking, tongue sucking, enlarged tonsils, high narrow arched palate, tethered oral tissue (tongue- tie), and low tonicity of the muscles. The two main causes are most likely, prolonged sucking habits and airway problems

Mouth Breathing - Open Mouth Rest Posture 

A thorough evaluation is required to determine whether the lips apart, open mouth rest posture is a habit due to past upper respiratory problems or if there is a medical concern that needs to be addressed. Medical conditions may include enlarged tonsils and or adenoids, allergies, seasonal sinus.

Mouth Breathing Open Mouth Rest Posture
Once a determination of cause has been established a course of treatment is set forth. Treatment of lips apart, open mouth, rest posture consists of a series of exercises that will ultimately result in functional nasal breathing. If the open mouth rest posture is not corrected it not only is detrimental to a successful orthodontic treatment plan, but it may be a contributing factor to orthodontic relapse. Furthermore, when the lips remain open, the tongue will drop down and forward resulting in an incorrect spring off point for articulation making it difficult to generalize speech sound productions into conversational speech.

Symptoms of Airway Problems

• Open mouth rest posture of the lips

• Low forward tongue rest posture

• Short upper lip with lip incompetence

• Prominent upper incisors

• V-shaped hard palate with narrow posterior maxillary dentition and high vault

• Everted, flaccid “pouting” lower lip Open bite

• Chapped, cracked lips

• Crease on nose (from “allergic salute”)

• Dark circles under eye