Studying the effects of skeletal class 2 and 3 malocclusions on speech sounds by phonetic analysis

Speech sounds can be affected from many factors such as skeletal and dental malocclusions, hearing problems, neurological disorders, craniofacial deformities. The purpose of this study was to compare the effects of malocclusions of patients who have different skeletal anomalies on the speech sounds by using phonetic analysis methods. This study was carried out at Gaziantep University Faculty of Dentistry Department of Orthodontics. The voice recordings and cephalometric radiographs were taken after the orthodontic treatment of patients with class 1 occlusal relationship and before the orthodontic treatments of patients with class 2 and class 3 malocclusions. A total of 60 patients were included in the study with 20 patients in each group. Speech texts were created to examine the change on the speech sounds. The voice recording process was performed in an insulated voice recording room. The labio-dental, dental, and alveolar consonants, / f /, / s /, and / ş / were selected for evaluation. Following the segmentation process after recording, the intergroup differences were analyzed by examining the values of spectral moments such as spectral center of gravity, standard deviations, skewness and kurtosis. The correlation between the cephalometric measurements and the acoustic parameters was investigated after acoustic analysis. Consequently, changes related to malocclusion were found on the sounds examined by acoustic evaluation, but a moderate correlation was observed with cephalometric measurements.