Effects of fixed labial orthodontic appliances on speech sound production

OBJECTIVE: To explore the impact of fixed labial orthodontic appliances on speech sound production. MATERIALS AND METHODS: Speech evaluations were performed on 23 patients with fixed labial appliances. Evaluations were performed immediately prior to appliance insertion, immediately following insertion, and 1 and 2 months post insertion. Baseline dental/skeletal variables were correlated with the ability to accommodate the presence of the appliances. RESULTS: Appliance effects were variable: 44% of the subjects were unaffected, 39% were temporarily affected but adapted within 2 months, and 17% of patients showed persistent sound errors at 2 months. Resolution of acquired sound errors was noted by 8 months post-appliance removal. Maladaptation to appliances was correlated to severity of malocclusion as determined by the Grainger's Treatment Priority Index. Sibilant sounds, most notably /s/, were affected most often. CONCLUSIONS: (1) Insertion of fixed labial appliances has an effect on speech sound production. (2) Sibilant and stopped sounds are affected, with /s/ being affected most often. (3) Accommodation to fixed appliances depends on the severity of malocclusion.