The incidence of orofacial myofunctional disorders (OMD) refers to the number of new cases identified in a specified time period. The prevalence of OMD refers to the number of individuals who exhibit OMD at any given time.
Estimates vary according to the definition and criteria used to identify OMDs, as well as the age and characteristics of the population (e.g., orthodontic problems, speech disorders, etc.).
- Tongue thrusting (protrusion of the tongue between the teeth) during swallowing is estimated to range between 33% and 50.5% of the general population of school-aged children (Fletcher, Casteel, & Bradley, 1961; Gross et al., 1990; Hale, Kellum, Nason, & Johnson, 1988; Hanson & Cohen, 1973; Wadsworth, Maul, & Stevens, 1998).
- The presence of tongue thrusting (the protrusion of the tongue between the teeth) during swallowing is significantly related to age. Prevalence estimates are highest in preschool- and young school-aged children and lowest in adolescents (Fletcher, et al., 1961; Wadsworth, et al., 1998).
- Children with articulation disorders are more likely to exhibit a tongue thrust swallow (55.3%; Wadsworth, et al., 1998).
- Approximately 31% of children diagnosed with chronic mouth breathing (a common symptom of OMD) exhibit an articulation disorder (Hitos, Arakaki, Sole, & Weckx, 2013).
- Higher estimates are reported for individuals receiving orthodontic treatment (62% to 73.3%) or with dental malocclusions (Hale, Kellum, & Bishop, 1988; Stahl, Grabowski, Gaebel, & Kundt, 2007).
- In individuals with a temporomandibular disorder (TMD), the percentage of those with orofacial myofunctional variables is estimated to be 97.92% (Ferreira, Da Silva, & de Felicio, 2009).