[Changes on pronunciation using the removal appliance for children with early loss of deciduous teeth. Comparison between good occlusion children with missing anterior-posterior deciduous teeth].

The purpose of this study was to examine missing anterior teeth and posterior teeth for possible differences according to the where the teeth were missing site, a comparison was made between children with such defects and those with relatively good occlusion. The following results were obtained: 1. Compared with children with missing anterior teeth, children with missing posterior teeth showed more differences in the frequency range for vowel formants from those with relatively good occlusion. 2. As for vowel formant, missing anterior teeth and missing posterior teeth presented more such differences for formant i and formants i and e, respectively. 3. For each formant, more such differences were noted for the first formant and the third formant compared with comparatively fewer such differences noted for the second formant. 4. In terms of the strength of voice components in each frequency range, consonant pronunciation rather than vowel pronunciation proved to be influenced by missing either anterior or posterior teeth. 5. For vowel pronunciation, more such differences were noted at low to intermediate frequency ranges. 6. Pronunciation of words containing the letter t and k tended to be improved for missing anterior and posterior teeth, respectively, but pronunciation proved to be improved in a difficult manner. The above results revealed that compared with missing anterior teeth, missing posterior teeth presented more differences from children with relatively good occlusion, suggesting that not only space maintenance and masticatory function but also speech function must be considered in preparing the removal appliance for missing posterior teeth of children.