Occurrence of bruxism in individuals with autism spectrum disorder: A systematic review and meta-analysis

Aims: To investigate bruxism in individuals with autism spectrum disorder (ASD) and neurotypical individuals. Methods and results: Searches were conducted in the MedLine via Ovid, Embase via Ovid, Cochrane Database of Systematic Reviews, Scopus, Web of Science, Latin American and Caribbean Health Sciences (LILACS), Brazilian Library of Dentistry (BBO) and SciELO databases, grey literature and a hand search up to December 2020 with no restrictions imposed regarding language or year of publication (CRD42020211307). For the meta-analysis, the frequency of bruxism was extracted, with the calculation of odds ratios (OR) and 95% confidence intervals (CI) using a random effects model in RevManager. The certainty of the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE). Seventeen case-control studies were included in the qualitative synthesis and 15 were included in the meta-analysis, totaling a population of 3850 individuals. The ASD group was more likely to develop bruxism than the controls (OR: 3.80; 95% CI: 2.06-7.01). The certainty of the evidence was classified as "very low" for the occurrence of bruxism between ASD and control individuals. Conclusion: It is uncertain whether individuals with ASD are more likely to have bruxism than healthy controls.