Association Between Occlusal Wear, Viscoelastic Properties, and Pain in Masticatory Muscles in Individuals With or Without Headache and Neck Pain: A Pilot Cross-Sectional Study.

Objectives: Malocclusion and occlusal wear are identified as potential risk factors for altered masticatory muscle function, pain, and temporomandibular joint (TMJ) dysfunction. This study aimed to assess the correlation between occlusal discrepancies, viscoelastic properties, and pain scores in the muscles of mastication-temporalis, masseter, pterygoids, and sternocleidomastoid muscles-in individuals with and without head and neck pain (HNP). Methods: This pilot exploratory study included 38 participants (10 men and 28 women) divided into 18 patients without HNP (control) and 20 with HNP (case). The following parameters were assessed: severity of tooth wear by the "Individual (personal) Tooth-Wear Index" by Ekfeldt et al. (1990); viscoelastic properties (tone, stiffness, and elasticity) of masticatory muscles (masseter, temporalis, sternocleidomastoid, lateral pterygoids, and medial pterygoid muscles) using Mytone Pro; and pain scores using the numeric rating scale. Stress and anxiety were assessed using the perceived stress scale (PSS) and the Hamilton anxiety (HAM-A) scale, respectively. Correlation analyses between occlusal wear and viscoelastic properties of each muscle of mastication were conducted using Pearson's correlation coefficient. For all analyses, statistical significance was set at Results: Participants with HNP exhibited greater mean occlusal wear (8.417 ± 4.54) than those without HNP (6.626 ± 3.72). The frequency and stiffness of the masseter and sternocleidomastoid muscles were significantly greater in individuals with HNP. Pain scores for the muscles of mastication were higher in patients with HNP than in those without HNP. The average pain scores in the muscles of mastication were notably higher in those with HNP (mean = 5.9) than in those without HNP (mean = 3.2). The relaxation time and creep were also reduced in the masticatory muscles of patients with HNP. However, no correlation was observed between masticatory muscle pain and occlusal wear. Conclusion: Stiffness and relaxation time in the masticatory muscles were greater in individuals with HNP. Occlusal wear affects the viscoelastic properties (tone, relaxation, and stiffness) of the masticatory muscles and is positively correlated with HNP. A multidisciplinary approach involving dentists, neurologists, and physiotherapists is essential for effectively managing patients presenting with headaches, occlusal discrepancies, muscle dysfunction, and craniofacial pain.