Clear Twin Block Versus Traditional Twin Block: a Clinical Electromyographic Comparison

Background: Functional appliances such as twin blocks are widely used to treat skeletal Class II malocclusions. Myofunctional effects are one of the critical features of these appliances. The present study aimed to investigate the muscular effects of clear and traditional twin blocks.Methods: In this randomized clinical trial, ۶۰ skeletal Class II division ۱ patient were randomly divided into two groups: clear twin block (CTB) and traditional twin block (TTB). Electromyographic (EMG) evaluation of masseter, anterior temporalis, orbicularis oris, and mentalis muscles was carried out during deglutition, rest, whistling, and forced occlusion before insertion (T۱) and six months (T۲) after insertion of the appliance. Data were analyzed using independent t-test, paired t-test, and Wilcoxon’s signed rank at the ۰.۰۵ significance level.Results: There were no significant differences in T۲ values between the groups (P>۰.۰۵). The intragroup comparisons showed a significant change from T۱ to T۲ in the CTB group for the clenching of the masseter muscle and in the TTB group for swallowing and rest position of the anterior temporalis muscle and swallowing of the masseter muscle (P<۰.۰۵).Conclusion: Both CTB and TTB changed the muscular activity of circumoral muscles. No significant difference was found when the post-treatment muscular activity of the two groups was compared.

کلیدواژه ها:

EMG ، Clear Twin block ، Muscle ، Skeletal Class II