Immediate effects of myofascial release and post-isometric relaxation on muscle properties and pain in symptomatic bruxism: A randomized, controlled, double-blind trial

Objective: This double-blinded randomized controlled trial investigated the immediate effects of myofascial release (MFR) and post-isometric relaxation (PIR) on muscle stiffness, tone, pain, and maximum mouth opening (MMO) in individuals with bruxism, compared with a control group. Methods: Sixty participants were randomized into MFR (n = 20), PIR (n = 20), or control groups (n = 20). Each intervention was a single standardized session. The primary outcomes were muscle stiffness and tone, while secondary outcomes included pain severity (VAS), and MMO. Results: Both MFR and PIR significantly reduced masseter and sternocleidomastoid stiffness and tone (p <.05), except left sternocleidomastoid stiffness in MFR, with no changes in controls. MFR was superior to control for pain (p =.010) and masseter stiffness (p =.030), while PIR showed superiority only for left tone (p =.034). Both interventions reduced VAS scores (p <.001) and improved MMO (p <.05). Conclusion: A single MFR or PIR session reduced stiffness, tone, and pain and improved MMO in bruxism. MFR showed stronger effects, whereas PIR yielded limited benefits.