Anterior palatal form affects the speech and is one of the important factors for the fabrication of upper denture. Air pressure in the incisor region was measured to examine the influence of the anterior palatal form on speech in the previous report. In the present study, the palatogram and jaw position were measured during the utterance of Japanese/sa/, /si/, /ta/, and /ci/. Subjects used and the experimental denture were the same in the report.
The results were as follows:
1. Palatogram was influenced by alterations of anterior palatal form. The thicker the anterior palatal counter, the posterior construction for fricative or plosive in the palatogram positioned during the utterances of /sal, /si/ and /ci/. The influence of the anterior palatal form was not observed during the utterance of /ta/.
2. The alterations of anterior palatal affected significantly the mandibular position. No general tendency was observed regardless of subjects.
The tongue movements primarily compensated alterations of anterior palatal form. This experiment confirmed that adequate anterior palatal form, i.e., width and location of S-ridge and the location, is important for the /s/sound production.
