Objective: To analyse the effects of clear aligner therapy (CAT) on patients affected by sleep bruxism, recording the effects of CAT on masseter contractions and the overall sleep bruxism index during sleep.
Materials and methods: 40 subjects requiring orthodontic treatment and affected by sleep bruxism (17 men, 23 women, 26 ± 5 years) were enrolled and randomly assigned to either the CAT group, with 20 subjects undergoing orthodontic treatment with aligners (8 men, 12 women, 20 ± 6 years), or placebo group (9 men, 11 women, 25 ± 3 years), with 20 subjects wearing a Begg appliance without occlusal coverage. After dropouts were removed, the study was conducted on a total of 34 subjects (13 men, 21 women, 21 ± 6 years), with 17 in the CAT group (6 men, 11 women, 19 ± 4 years) and 17 (7 men, 10 women, 24 ± 3 years) in the placebo group, followed for 1 year. Sleep bruxism index and electromyographic signals were recorded using a portable electromyographic-electrocardiographic device (Bruxoff, Bioelettronica, Turin, Italy) at baseline (T0), after 1 month (T1), 3 months (T2), 6 months (T3) and 12 months (T4).
Results: CAT produced no significant changes in the sleep bruxism index. A reduction in masseter contractions, more specifically general phasic contractions not related to sleep bruxism, was observed after 1 year of treatment in patients wearing clear aligners (P < 0.05).
Conclusion: The use of CAT in orthodontic patients does not influence the sleep bruxism index, but can affect some specific electromyographic background signals.