During the orthodontic treatment, the orthodontic appliances that are positioned intraorally may result in articulation problems, especially the distortion of some consonants. The effect on phonetics by orthodontic appliances especially lingual orthodontic appliances is revealed in some researches. This kind of speech defect could mostly disappear during treatment, which might be attributed to the compensation of the oral articulators such as lip and tongue. Besides, appropriate clinical measures and speech training can shorten the duration of phonetic problems. This review gives a introduction about the effect on phonetics by orthodontic appliances, covering the mechanism, scientific evidences, improvement measures and some clinical recommendations.
