Assessment of the Pronunciation in Subjects with Sound Dentition

Objectives: The objective of this study was to investigate and standardize the speech intelligibility of consonants in normal subjects with sound dentition in order to apply to the patients with missing teeth.

Methods: The subjects of this study consisted of 29 patients, who had the personal normal occlusion with sound dentition; 6 males and 23 females; 23-74 years old. Each subject was instructed to pronounce the test words of Japanese proper noun which were including the test sounds [Si], [Chi] or other syllables. Each pronunciation was recorded and analyzed with the speech recognition program (Voice Analyzer, TOSHIBA Digital Media Engineering Co., Japan). This program was transferred automatically the phonetic signals to the signs which were called phonetic segment labels in every 8 msec. The labels correctly recognized were defined as correct labels, and distribution of correct and incorrect labels was analyzed. The appearance ratio of the labels in each condition was evaluated with repeated measures one-way ANOVA, with Tukey's multiple comparison tests. P-Values<0.05 were considered significant.

Results: The average appearance ratio of the correct labels of [Si] showed 91.3±7.9% in normal subjects with sound dentition. This value was significantly higher than that of the denture wearers; 76.0±16.4 % extracted from our former studies. On the other hand, the incorrect labels corresponding to the affricate [Chi] and [Hi] tended to be less appeared.

Conclusion: The results of this study represented standard intelligibility of monosyllable consonants based on the average appearance ratio in normal subjects with this system would be helpful for evaluating phonetic function of the patients with dentures on the dental chair-side.