A Prospective Evaluation of Speech Distortion among Patients Wearing Hawley Retainer Using Acoustics Approach

Abstract

1.1.Background: Orthodontic retainers constrict the oral cavity’s dimension and restrict tongue movement during articulation, resulting in distortions of various sounds. Speech impairment is among the main reason for poor patient compliance in wearing the retainers which leads to treatment relapse. 1.2.Objectives: To determine and describe the changes of the distorted sounds in patients wearing upper and lower Hawley retainer. 1.3.Materials and methods: Sixteen orthodontic patients who were at the end of fixed appliance phase were included as subjects in this study. They were all speakers of native Malay, aged between 15 to 31 years old. The sound sample of selected phonemes with /t/, /d/, /k/ and /n/ consonant were recorded from the subjects before wearing (T0), immediately after wearing retainers (T1), and at 1 week (T2), 2 weeks (T3), 1 month (T4), 2 months (T5) and 3 months (T6) of wearing the retainers. Based on the recordings, acoustic analysis was performed objectively on each subject to determine the duration value of selected phonemes at each interval. 1.4.Results: All phonemes tested showed significant speech distortion (p 0.008). Conclusions: A marked distortion of /t/, /d/, /k/ and /n/ consonant sounds were observed in patients during the initial wearing of Hawley retainer. Patient needs to be well informed of the changes and encouraged for constant wearing. With good cooperation, speech will be adapted to normal pattern within 3 months.