Effectiveness of oral motor appliances on oral motor function and speech in children: a systematic review

Different oral motor appliances have been used in connection with speech therapy to improve oral motor function and speech development, but no consensus has been reached on the effectiveness of the appliances. The objective was to systematically review the effectiveness of oral motor appliances on oral motor function and speech in children with speech sound disorders (SSDs) or oral motor dysfunctions.

A systematic search was conducted up to February 2023 in the PubMed, Scopus, and Cochrane databases. Inclusion criteria were prospective randomized or case-control clinical trials investigating the effect of intraoral appliances on orofacial function and/or speech. The risk of bias was evaluated by the Cochrane Collaboration's Robins-I tool.

Nine publications of three individual studies met the inclusion and search criteria. Six of the publications were conducted in children with Down Syndrome (DS) and three publications were conducted in children with Cerebral Palsy (CP). No meta-analysis was made due to the limitations of the publications. Selected studies reported some beneficial effects of intraoral appliances on oral motor function in children with DS and CP, although the evidence is low. Due to the study design in selected studies and confounding factors, the overall risk of bias was categorized as moderate or high.

Intraoral appliances may improve oral motor function in children with DS and CP. Due to lack of studies this review limited to children with DS and CP. The initial question concerning SSDs was not answered. Well-designed RCTs with larger sample sizes are needed, especially among non-syndromic children with SSDs. The level of evidence was considered very low.