Introduction. Four years of observations of speech and oral muscle patterns in orthodontic patients have led the examiners to expect certain factors to occur frequently. These factors include open-mouth posture, low forward tongue position at rest, llnguadental instead of linguaalveolar articulatory placement, linguadental tongue position and lip movement during swallowing, upper lip restriction, mentalis wrinkling, frenum restriction, negative oral habits, and articulation and voice disorders. The emergence of these predictable patterns suggested the need for a systematic study of their occurrence. Thus, the incidences of speech differences, negative oral behaviors, and muscle factors identified as correlates to abnormal oral muscle, skeletal, and dental growth were examined in a retrospective study of the records of 229 orthodontic patients, the entire number of new patients reporting for records appointments to an orthodontic practice within a calendar year.
Hale, S. T., et al. (1988). Prevalence of oral muscle and speech differences in orthodontic patients, International Journal of Orofacial Myology, 14 (2), 6-10.