The relationship between the mandibular movements during speech and specific types of malocclusions.

To investigate the effect of malocclusion on mandibular movements during speech, the location, width and height of the envelope of motion during speech were analyzed in 25 normal subjects and 60 subjects with malocclusion using the Sirognathograph Analyszing System. Location of the envelope of motion was closely related to the specific types of malocclusions. It is suggested that the analysis of the envelope of motion during speech has diagnostic values in speech function and dental treatments.