Respiratory Function, Muscle Biomechanics, and Pain Sensitivity in Individuals With Bruxism

Abstract

Background Bruxism is a multifactorial condition characterized by repetitive masticatory muscle activity that may influence not only the stomatognathic system but also cervical muscle biomechanics and respiratory function. This study aimed to investigate pulmonary function, biomechanical properties, and pressure pain sensitivity of the masticatory and cervical muscles in individuals with bruxism compared to healthy controls. Methods This prospective cross‐sectional study included 43 participants aged 18–40 years (bruxism group: n = 24; control group: n = 19). Bruxism was determined using a self‐reported frequency score derived from the Fonseca Anamnestic Index. Muscle tone and biomechanical properties of the masseter, temporalis, sternocleidomastoid, splenius capitis, and upper trapezius muscles were assessed bilaterally at rest using the MyotonPRO device. Pressure pain threshold (PPT) and pain tolerance were evaluated with a digital algometer. Pulmonary function parameters (FVC, FEV 1 , FEV 1 /FVC, PEF) were measured via spirometry in both sitting and supine positions. Results No significant differences were observed between groups in biomechanical properties of the masseter, temporalis, sternocleidomastoid, or upper trapezius muscles ( p > 0.05). However, the bruxism group showed higher oscillation frequency and dynamic stiffness values in the splenius capitis muscle bilaterally ( p < 0.05). Pain parameters were similar between groups for all muscles ( p > 0.05). Pulmonary function across positions and positional differences did not differ between groups ( p > 0.05). Conclusion Bruxism‐related biomechanical alterations appear to be selectively localized to the splenius capitis muscle under resting conditions, while pain sensitivity and pulmonary function remain unaffected.