Association between attention deficit hyperactivity disorder and bruxism: a systematic review

Background Attention-deficit/hyperactivity disorder (ADHD) is a prevalent neurodevelopmental condition characterized by symptoms of inattention, disorganization, and/or hyperactivity-impulsivity. Bruxism, defined as repetitive masticatory muscle activity involving clenching or grinding of the teeth and/or forceful mandibular movements, has been associated with several physiological and psychosocial factors. Considering the neurobehavioral profile of individuals with ADHD, a possible association between ADHD and bruxism has been hypothesized. Aims To determine whether an association exists between ADHD and bruxism. Methods A comprehensive literature search was conducted across five electronic databases and two gray literature sources. Observational studies comparing individuals with ADHD to non-ADHD controls, with data on the presence of bruxism, were included. Independent authors conducted study selection and data extraction. Risk of bias was assessed using the JBI critical appraisal tools. A pairwise meta-analysis was performed using RevMan Web. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a random-effects model. Results: Sixteen studies with 16,348 participants were included. The pooled OR indicated that individuals with ADHD were two times more likely to present bruxism compared to controls (OR 2.16; 95% CI 1.72-2.71; p < 0.00001, I2 51%). Subgroup analyses by age group showed a consistent association across children, adolescents, and adults. Moderate heterogeneity and potential small-study bias (with little impact on the pooled results after sensitivity analysis) were observed. Conclusions Current evidence supports a possible association between ADHD and bruxism.