Effects of Invisalign^® treatment on speech articulation

Objectives: To determine the effects of Invisalign^® aligners on patients’ abilities to articulate consonants. Materials and methods: Thirty patients undergoing active two-arch Invisalign^® treatment were examined. Patients were recorded reading the rainbow passage (a passage with every phoneme represented), once with the trays inserted and once with the trays removed. The recordings were analysed by a speech pathologist for misarticulation of consonant phonemes. Results: Misarticulation of consonants was significantly associated with the Invisalign^® aligners inserted as based on the McNemar's statistical test (P = 0.008). The fricative alveolar consonant /z/ was found to be the most impacted by the trays, followed by the consonant /s/ (P = 0.016). The consonant /sh/ was not shown to be affected by the Invisalign^® aligners. Conclusions: Invisalign^® aligners do have an impact on the articulation of consonants. Fricative alveolar consonants were the primary phonemes impacted. Due to the fact that the efficacy of Invisalign^® treatment is based primarily on compliance and that speech impairment may interfere with compliance, the information presented in this study should be conveyed to the patient before the initiation of Invisalign^® treatment.