The prefix, "myo" stands for muscle. Orofacial Myofunctional
Disorders involve behaviours and patterns created by inappropriate
muscle functional and incorrect habits involving the tongue,
lips, jaw and face. Of the many possible myofunctional variations,
those involving the tongue and lips receive the most attention.
A tongue thrust is the most common orofacial myofunctional
variation. During the act of swallowing, (deglutition), and/or
during rest posture, an incorrect positioning of the tongue
may contribute to improper orofacial development and maintenance
of the malalignment of the teeth.
An orofacial variation that relates to the lips is an open
mouth, lips apart resting posture. This is often referred
to lip incompetence and can distract from a pleasing facial
What Causes an Orofacial Myofunctional Disorder?
Often it is difficult to point to one particular source as
the sole cause of an orofacial myofunctional disorder. In
most cases it is the result of a combination of factors. Many
authorities suggest that orofacial myofunctional disorders
may result from the following:
• Improper oral habits: such as thumb or finger sucking,
cheek/nail biting, tooth clenching/grinding.
• Restricted nasal airway: due to enlarged tonsils/adenoids
• Structural or physiological abnormalities such as
a short lingual frenum (tongue-tie) or abnormally large tongue.
• Neurological or developmental abnormalities.
• Hereditary predisposition to some of the above factors.
Why Be Concerned?
Orofacial myofunctional disorders may have a negative effect
on the development of the dentition, particularly dental eruption
patterns and/or alignment of the teeth and jaws. Speech patterns
may become distorted or misarticulated. Para functional habit
patterns may have a negative influence on the functioning
of the temporomandibular joint.
Correcting or improving resting tongue or lip relationships
can be instrumental in aiding the development of normal patterns
of dental eruption and alignment.
Myofunctional therapy for tongue thrusting and lip incompetence
may be recommended for a variety of functional or cosmetic
reasons. If the patient already has orthodontic appliances,
correcting the myofunctional disorder can help stabilize the
orthodontic result by creating a more desirable and a healthier
Usually the therapy programs are designed to retrain patterns
of muscle function and to aid in the creation and maintenance
of a healthy, adaptive orofacial environment. Therapy can
help in the retention of the dental and/or orthodontic treatment,
can help enhance one's appearance and can help maintain optimum
dental health for a lifetime of benefits.