Quantitative assessment of masticatory function in patients with temporomandibular joint arthralgia: A study focusing on maximum bite force, chewing efficiency, chewing frequency, pressure pain threshold and mandibular range of motion

Objectives Patients with temporomandibular joint (TMJ) arthralgia typically claim joint function impairments negatively affecting their quality of life. Aim of this study was to quantitatively assess masticatory function with instrumental measures in a group of TMJ arthralgia patients and compare it to symptom-free controls. Materials and Methods Masticatory function data were collected in a sample of TMJ arthralgia patients (n = 14) and symptom-free controls (n = 19). Diagnosis of arthralgia and mandibular range of motion were obtained following the DC/TMD protocol. Bite forces, chewing frequency, variance-of-hue-based (VOH) chewing efficiency, and bilateral pressure pain threshold (PPT) of temporalis and masseter muscles were measured. Group differences were examined applying t-test for independent variables (level of significance α = 0.05). Results In the arthralgia group, pain-free, maximum unassisted and maximum assisted mouth opening were significantly restricted (p < 0.001, p = 0.004, p = 0.019, respectively), bite force and chewing frequency were significantly lower (p < 0.001), the average chewing efficiency was 0.16 ± 0.11 VOH, PPT for both masseter muscles was significantly reduced (p = 0.011 ipsilateral and p = 0.041 contralateral to the pain side) than in controls. Conclusions Functional markers including bite force, chewing frequency, PPT, and mouth opening range were limited in the patients with TMJ arthralgia when compared to controls. This is consistent with commonly reported subjective perception, allowing for an objective quantification of functional impairment. Clinical Relevance Instrumental measurements for symptom documentation in the clinical practice provides more objective data on functional limitations. Longitudinal observation of the parameters during treatment and the comparison of outcomes of different therapeutic approaches should accompany objective measures.