Differences of sound and morphology in skeletal class III patients

Abstract

[Background] This study aimed to explore differences in vowel production using acoustic analysis in skeletal Class III and Class I Japanese participants, and to investigate the correlation between vowel sounds and cephalometric variables in skeletal Class III subjects.

[Materials and Methods] Japanese males with skeletal Class III (ANB<0°) and Class I skeletal relationships (0.62°<ANB<5.94°) were recruited (n=18/group). Acoustic analysis of vowel sounds and cephalometric analysis of lateral cephalograms were performed. For sound analysis, an isolated Japanese vowel (/a/, /i/, /u/, /e/, /o/) pattern was recorded. Praat software was used to extract acoustic parameters such as fundamental frequency (F0) and the first four formants (F1, F2, F3, and F4). The formant graph area was calculated. For cephalometric analysis, cephalometric values were obtained by ImageJ. Correlations between acoustic and cephalometric variables in skeletal Class III subjects were then investigated.

[Results] Skeletal Class III subjects showed significantly higher /o/F2 and lower /o/F4 values. Mandibular length, SNB, and overjet of Class III subjects were moderately negatively correlated with acoustic variables.