Speech performance in adult patients undergoing Invisalign treatment:: A prospective clinical study

ObjectivesTo assess speech performance of adult patients undergoing orthodontic treatment with Invisalign.Materials and MethodsTwenty-four adult patients with Invisalign (Invisalign group: 6 men, 18 women; average age; 34.88 years) and 20 adult patients with fixed labial appliances (fixed group: 5 men, 15 women; average age; 38.85 years) were evaluated. Speech was recorded immediately before delivery of the first set of clear aligners or bonding of labial appliances (T₀), immediately after delivery or bonding (T₁), and 2 months after delivery or bonding (T₂). Speech was evaluated via a combination of three auditory analyses: (1) objective acoustic analysis through digital sonography, (2) semiobjective assessment by six speech and language pathologists, and (3) subjective assessment patient questionnaire.ResultsThe objective acoustic analysis showed a statistically significant difference over time from T₀ to T₁, T₁ to T₂, and T₀ to T₂ for Invisalign patients. The semiobjective analysis revealed a significant speech alteration from T₀ to T₁ and T₁ to T₂ for both groups, and from T₀ to T₂ in the Invisalign group. The subjective analysis showed a significant difference between means of Invisalign and fixed group patient perception at both T₁ and T₂.ConclusionsInvisalign treatment significantly affected speech, and although patients experience some level of adaptation, speech does not return to normal after 2 months of treatment.