Does short-term treatment with clear aligner therapy induce changes in muscular activity?

Area of Science:

• Orthodontics
• Biomechanical Engineering
• Dental Occlusion

Background:

• Clear aligners are increasingly used for orthodontic treatment.
• Understanding their impact on occlusal forces and muscle activity is crucial.
• Previous research has not fully elucidated these biomechanical changes over time.

Purpose of the Study:

• To evaluate the effects of clear aligner therapy on occlusal force distribution and muscle activity.
• To assess changes in the center of occlusal force (COF) and surface electromyography (sEMG) parameters over a 6-month period.
• To investigate the relationship between occlusal contact alterations and muscular balance during clear aligner treatment.

Main Methods:

• Prospective cohort study involving 26 adult female patients with Class I malocclusion.
• Surface electromyography (sEMG) and digital occlusal analysis (T-Scan) were performed at baseline, 3 months, and 6 months.
• sEMG assessed muscular symmetry (POC) and balance (TC, Ac, Asym); T-Scan evaluated COF position and maximal intercuspation time (MIC).

Main Results:

• Clear aligner use resulted in a significant anterior shift of the COF in centric occlusion and a posterior shift with aligners worn.
• Muscular symmetry (POC) improved with aligners but declined over time in centric occlusion.
• No significant changes in torque coefficient, activity index, asymmetry index, or maximal intercuspation time were observed.

Conclusions:

• Clear aligners alter occlusal force distribution, causing anterior COF displacement in centric occlusion and posterior displacement with aligners.
• Short-term improvements in muscular balance were noted with aligner use, followed by a decline in centric occlusion.
• No significant transverse plane asymmetries in COF position were detected.