Clear Aligners and Bruxism: A Systematic Review

Bruxism is a masticatory muscle activity that may occur during sleep (SB) or wakefulness (AB) and is not classified as a movement or sleep disorder. Clear aligner therapy, widely adopted as a removable and aesthetic orthodontic alternative, modifies occlusal contacts and mandibular dynamics, which may influence the occurrence or perception of bruxism behaviours.

To systematically review the association between clear aligner therapy and bruxism (SB, AW and mixed/self-reported), with a focus on evaluating its role as neutral, protective or a potential risk factor.

A systematic search of electronic databases and grey literature was conducted through April 2025, with included studies that identified bruxism using validated instrumental methods (portable electromyography for SB, or smartphone-based ecological momentary assessment for AB), subjective questionnaires on behaviours and related symptoms. Risk of bias was assessed using the Joanna Briggs Institute tool, and evidence quality was evaluated with GRADE.

Eleven studies evaluated 818 patients (72.8% female). Most studies suggested a neutral effect of clear aligners on bruxism. For SB, aligners often reduced tonic contractions but showed inconsistent effects on higher phasic activity and no changes on overall SB index. AB was generally unaffected, though one study reported reduced self-reported parafunctions with altered muscle recruitment. Mixed/self-reported bruxism outcomes were conflicting: some studies indicated improvements in clenching and TMJ pain, while others found a higher prevalence of bruxism symptoms during aligner therapy. Methodological heterogeneity and risk of bias were notable, precluding that no meta-analysis was possible. GRADE certainty for randomised studies was moderate and very low for non-randomised studies.

Current evidence on the relationship between clear aligner therapy and bruxism remains limited and heterogeneous. Most studies suggest a neutral effect, with occasional reductions in tonic contractions or symptom improvement, but also reports of increased phasic activity or self-reported bruxism. Overall, aligners cannot yet be classified as protective or harmful, highlighting the need for standardised, high-quality studies to clarify their role in bruxism management.