Clear Aligners and Bruxism: A Systematic Review.

Area of Science:

• Orthodontics
• Sleep Medicine
• Neurology

Background:

• Bruxism, a masticatory activity during sleep or wakefulness, is not a classified sleep disorder.
• Clear aligner therapy (CAT) alters occlusal contacts and mandibular dynamics, potentially influencing bruxism behaviors.

Purpose of the Study:

• To systematically review the association between clear aligner therapy and bruxism.
• Evaluate CAT's role as neutral, protective, or a risk factor for sleep bruxism (SB) and awake bruxism (AB).

Main Methods:

• Systematic search of databases and grey literature up to April 2025.
• Included studies used validated instrumental methods (portable EMG for SB, smartphone EMA for AB) or subjective questionnaires.
• Risk of bias and evidence quality assessed using Joanna Briggs Institute and GRADE criteria.

Main Results:

• Eleven studies (818 patients) suggested a mostly neutral effect of CAT on bruxism.
• CAT showed inconsistent effects on SB phasic activity but reduced tonic contractions; AB was generally unaffected.
• Mixed/self-reported outcomes were conflicting, with some reporting symptom improvement and others increased bruxism prevalence.

Conclusions:

• Evidence on CAT and bruxism is limited and heterogeneous.
• CAT is currently neither protective nor harmful for bruxism.
• Standardized, high-quality studies are needed to clarify CAT's role in bruxism management.