Orofacial Myofunctional Disorders (OMDs) are defined as behaviors and patterns created by inappropriate muscle function and incorrect habits involving the tongue, lips, jaw and face.

These may include tongue thrust (thrusting the tongue against or between the teeth during swallowing or at rest), thumb, finger, lip and tongue sucking habits, inappropriate tongue resting posture and open-mouth/lips apart resting posture.  

OMDs may negatively impact dental eruption patterns, alignment of the teeth and jaws and functioning of the temporomandibular joint (TMJ). Speech problems, including an interdental lisp may also develop.