Dentistry and speech production. Correlations between the morphology of the articulation zone and acoustics exemplified in /s/ articulation.

Many factors are thought to be responsible for misarticulation. Maxillomandibular or dental irregularities play an important role as one of these factors. Correlations between morphological changes in dental status and speech disorders are well known, but different opinions are discussed in the literature. A reciprocal relationship between dysfunction and various dental irregularities is assumed. The objective of our review and experimental investigations was to document the influence of dental irregularities on speech articulation as exemplified by the second articulation zone and /s/ articulation. The second articulation zone was experimentally changed by application of dental cement to the palatal surface of the upper incisors. Various words were spoken before and just after the change to the frontal teeth. The /s/ articulations were acoustically analyzed by means of sonography and compared with each other. Although this modification of the teeth, which was identical in all probands, leads to /s/ misarticulation from the standpoint of auditory analysis, interindividual differences were recorded by acoustic means. It is thus possible to differentiate objectively between acoustically correct and incorrect /s/ articulation. Speech and articulation are, however, such complex mechanisms that it is impossible to characterize them by simple causal connections with maxillomandibular or dental irregularities.