The effect of Invisalign on the articulation of speech
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Objectives: Orthodontic appliances are numerous. Assuming comparable final results of the various orthodontic appliances, impacts on the patient from the treatment should be examined. The objective of this study is to discover the effect that Invisalign aligners may have on a patient's ability to articulate consonants. Methods: 60 samples were obtained from 30 patients in active Invisalign treatment. Patients were recorded at any point in treatment reading the rainbow passage (a passage with every phoneme represented), once with the tray inserted and once with the tray removed. The recordings were analyzed by a speech pathologist for misarticulation of any consonant phoneme. Results: The study shows that misarticulation of consonants is generally associated with the Invisalign aligners as based on the McNemar statistical test, with a significance value of .008 (P<.05). The consonant /z/ was found to be the most impacted by the trays, with a significance of .008(P<.05), followed by the consonant /s/. The consonant /sh/ was not shown to have a statistically significant result (P>.05). Out of the 30 patients, 2 misarticulated the consonant /s/ without the aligner and 8 with the aligner. The consonant /z/ was misarticulated by two patients without the aligners and 9 patients with the aligner. Conclusion: Invisalign aligners do have an impact on articulation of consonants. Specifically, 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 initiation of Invisalign treatment. The results presented herein become even more significant taking into account that Invisalign is often presented as a treatment alternative to lingual braces in a scenario when a patient is particularly disconcerted with the speech effects of lingual brackets. This study confirms that Invisalign also has an effect on articulation. The outcomes presented by this study are clinically relevant to the orthodontist given the removable nature of Invisalign. During Invisalign treatment, in order to alleviate the effect on speech, a patient may choose to remove the aligners. As such, a patient who opts to remove the Invisalign aligners for more than two hours a day will not be wearing the tray sufficiently to gain full expression of the aligner. Therefore, a patient should fully understand the impact on speech of Invisalign prior to making a decision between treatment modalities.