Effects of therapy on masseter activity and chewing kinematics in patients with unilateral posterior crossbite

•Before therapy, unilateral posterior crossbite showed evident effects on mastication.•Masseter muscle coordination and chewing kinematics were evaluated after therapy.•The percent difference between bilateral masseter activity significantly increased on the crossbite-side.•The percentage of reverse cycles significantly decreased after therapy.•Mastication after therapy showed a significant symmetrization between sides.