This study was performed to investigate the effects of occlusal appliance on speech pattern, especially, related to the articulation of fricatives and affricates. For this study, twenty dental students, 10 male and 10 female, served as subjects. Subjects were asked to read fricative /s/ followed by Korean monophthongs in 7CVCV type syllables and four sentences including fricatives(s??, s?, s?) and affricates(t???, tf???. t???, t??, t??, t??, ??), in the four different speech environments, namely, speaking without splint(normal), with upper CR splint(up), with lower CR splint(down), and with anterior jig(jig), The recorded speech data were analyzed by CSL?(Computerized Speech Lab, Model 4300B, USA) and Wavesurfer. The statistical analysis was performed using SPSS Windows?(ver. 10.0) program. The results of this study were as follows: For the energy distribution type of fricative /s/ followed by Korean single vowels, scattered type was increased by splint regardless of vowel type. These changes were more significant in men, and in high vowels. Frication noise duration of fricative /s/ were not changed by splints, but peak energy frequency were decreased by splints both in male and in female subjects.
In fricatives(s??, s?, s?), frication noise duration were decreased in ´s??´, but increased in ´SA´ and ´so´ by splints. Aspiration duration, however, did not show any consistent tendencies.
In affricates, frication noise duration in men were longer than that of women without regard to the position in a word or in a sentence and properties of aspiratedness and/or tenseness. Frication noise duration by splints were variable according to the word and aspiration duration did not show any significant change by splints.
Peak energy frequency of almost all fricatives(s??, s?, s?) and affricates(t???, t???, t??, t??, t???, t??, t??) were decreased by splints.
In summary, by splints, measured absolute value of frication noise duration, aspiration duration, and peak energy frequency showed a tendency of change or were significantly changed for some specific words, but the ranks among the observed words did not changed in almost all situations by splints. So these results suggests that the pronunciation of words or sentences with splint can cause some problems phonetically, but still could be differentiated phonologically.
|