The effect of clear aligners on speech: a systematic review

Abstract

Objective To assess the effect of clear aligners on the speech of patients undergoing orthodontic therapy through a systematic review of the literature. Search methods and selection criteria: The protocol of this systematic review was registered in the International Prospective Register of Systematic Reviews (PROSPERO) CRD42021278694. An electronic search of the Scopus, Embase, Pubmed, and Web of Science databases was done for papers published between January 2000 till September 2021. Studies that evaluated speech difficulties in patients undergoing orthodontic treatment with clear aligners using objective and subjective analyses were included. The evaluated primary outcome was speech difficulties. Secondary outcomes were time to adaptation and recovery from speech difficulties. Study quality was assessed based on the Cochrane Handbook for Systematic Reviews of Interventions Handbook guidelines and ROBINS-I tool. Results Two hundred and eighty-three articles were screened to identify seven studies (n = 332 patients) that assessed speech difficulty with aligners, of which two were randomized trials. Meta-analysis was not performed due to the heterogeneity in the study designs. Five studies compared speech difficulty with aligners to fixed appliances. Two studies showed a moderate risk of bias and five studies had a serious risk of bias. Level of evidence was downgraded to low due to the methodological insufficiencies and risk of bias in the studies. All seven studies reported that aligners could influence the clarity and delivery of speech, similar to fixed appliances. Various phonemes were affected including /s/,/z/,/zh/,/sh/,/th/,/ch/ on wearing aligners. Errors in articulation of consonants and sibilants were noted with lisping and speech impairment. These speech difficulties were temporary and most patients recovered in 7–14 days while few patients took 30-60 days to recover. Conclusion The likelihood of speech difficulties appears high with clear aligners. However, patients adapt quickly and speech returns to normal. The results of this review must be interpreted with caution and more well-designed randomized trials examining long-term effects of aligners on speech are indicated. Clinical Significance Orthodontists should counsel patients opting for clear aligner treatment of the potential transient speech difficulties. Registration The protocol for this systematic review was registered in the International Prospective Register of Systematic Reviews (PROSPERO) CRD42021278694.

Orthodontic aligners: between passion and science

“…41 It is common that during orthodontic treatment patients experience some discomfort during the adaptation process, because the devices cause pain or even interfere with tongue movements, limiting the space for tongue accommodation and therefore the patient's speech. 42,43,44 Mendes Ribeiro SM, Aragón MLSC, Espinosa DSG, Shibasaki WMM, Normando D -Orthodontic aligners: between passion and science Because they are plates that cover the tooth surface, aligners may cause discomfort to the patient in verbal articulation. 38 Several studies have reported that esthetic aligners can influence the clarity and articulation of speech, in a more pronounced way than fixed appliances.…”

Immediate effect of clear aligners and fixed appliances on perioral soft tissues and speech

“…Following the collection of each image, participants were asked to read a script aloud, comprising their name, age, educational qualification, and corresponding address at baseline (pre-intervention) and while wearing the clear aligners and fixed appliances, respectively. 16,17,22,23 Participants then answered the question: "Do you feel that your speech has changed?". Responses were provided on a four-point Likert scale with possible answers including: (1) "No, not at all"; (2) "Slightly";…”

“…Orthodontic appliances can affect movement of the tongue and space in the oral cavity, leading to the distortion of speech 14‐16 . Prior investigations have described the effect of fixed appliances, removable appliances and orthodontic retainers on speech 14,17‐22 .…”

“…Orthodontic appliances can affect movement of the tongue and space in the oral cavity, leading to the distortion of speech. [14][15][16] Prior investigations have described the effect of fixed appliances, removable appliances and orthodontic retainers on speech. 14,[17][18][19][20][21][22] Speech changes reportedly occur with placement of both fixed labial and lingual appliances but speech patterns were found to gradually improve to pre-intervention levels within 1 month for patients treated with fixed labial appliances whereas patients with linguallybonded appliances continued to exhibit speech difficulties beyond 3 months.…”

Orthodontic pretreatment with aligners for optimizing the result prior to fixed restorations in the esthetic zone

“…The aligners may lead to initial speech difficulties. However, most patients adapt quickly and speech returns to normal 13 . For effective three‐dimensional tooth movements such as anterior root torque, rotation, mesio‐distal movement and intrusion or extrusion, these aligners may require adhesive composite attachments, 14 that are tooth‐colored and like the clear appliances itself almost not visible.…”