Effect of bimaxillary orthognathic surgery on acoustic analysis of vowels

Abstract Aim: Bimaxillary orthognathic double chin surgery is performed for therapeutic purposes in patients with occlusion disorders due to dentofacial deformity. We aimed to show the effect of this procedure on sound acoustics.Materials and Methods: The study was planned as retrospective and cross-sectional. Information about patients who applied to our center due to developmental malocclusion between 2018 and 2020 was examined. A total of 26 patients, 13 males and 13 females, who underwent orthognathic double jaw surgery after orthodontic treatment, were included in the study. Vowel (a,e,i,ı,o,ö,u,ü) recordings of the patients were analyzed before the surgery and at the 6th month after the surgery. Sound recordings were taken with the Audacity program (Open Source Software). The recordings were analyzed with the Praat acoustic analysis program. Before and after surgery for each letter; Fundamental frequency, Shimmer, Jitter and Harmony Noise Ratios were examined. Measurements taken before and after surgery were compared.Results: A decrease in fundamental frequency, jitter, shimmer and harmony noise values was detected. This can be interpreted as an increase in sound quality. A statistically significant change was detected in at least two parameters for each letter.Conclusion: Orthognathic double chin surgery performed due to dentofacial deformity provides an increase in the pronunciation of vowels and voice quality. To increase the reliability of the result, acoustic analysis was performed with multiple parameters.