• Heredia-Rizo AM
• Oliva-Pascual-Vaca A
• Rodríguez-Blanco C
• Piña-Pozo F
• Luque-Carrasco A

• Head / physiology
• Masticatory Muscles / physiology
• Mechanoreceptors / physiology
• Mouth
• Myofascial Technique
• Pain Threshold
• Posture

Objective: This study aimed to assess the immediate effects on masticatory muscle mechanosensitivity, maximal vertical mouth opening (VMO), and head posture in pain-free healthy participants after intervention with myofascial treatment in the temporalis and masseter muscles.

Methods: A randomized, double-blind study was conducted. The sample group included 48 participants (n = 48), with a mean age of 21 ± 2.47 years (18-29). Two subgroups were defined: an intervention group (n = 24), who underwent a fascial induction protocol in the masseter and temporalis muscles, and a control group (n = 24), who underwent a sham (placebo) intervention. The pressure pain threshold in 2 locations in the masseter (M1, M2) and temporalis (T1, T2) muscles, maximal VMO, and head posture, by means of the craniovertebral angle, were all measured.

Results: Significant improvements were observed in the intragroup comparison in the intervention group for the craniovertebral angle with the participant in seated (P < .001; F_1,23 = 16.45, R² = 0.41) and standing positions (P = .012, F_1,23 = 7.49, R² = 0.24) and for the pressure pain threshold in the masticatory muscles, except for M2 (P = .151; M1: P = .003; F_1,23 = 11.34, R² = 0.33; T1: P = .013, F_1,23 = 7.25, R² = 0.23; T2: P = .019, F_1,23 = 6.41, R² = 0.21). There were no intragroup differences for the VMO (P = .542). Nevertheless, no significant differences were observed in the intergroup analysis in any of the studied variables (P > .05).

Conclusion: Myofascial induction techniques in the masseter and temporalis muscles show no significant differences in maximal VMO, in the mechanical sensitivity of the masticatory muscles, and in head posture in comparison with a placebo intervention in which the therapist's hands are placed in the temporomandibular joint region without exerting any therapeutic pressure.

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