Is proprioception affected in those with persistent intra-articular temporomandibular disorders? A cross-sectional study exploring joint position sense and force sense of the jaw

Proprioception is an important component of normal jaw function, although to date it is unknown if and how proprioception is affected in those with intra-articular temporomandibular disorders (IA-TMDs). This challenges effective management of this subgroup. Determine whether differences in local joint position sense and force sense exist between individuals with IA-TMD and those without a jaw problem. Cross-sectional study. Sixty age and sex matched participants were recruited (n = 30 IA-TMD, n = 30 healthy controls). Temporomandibular joint position sense was tested to one target (50% of maximal mouth opening) using a ruler. Temporomandibular force sense was tested to two targets (50% and 70% of maximal molar pain-free bite force) using a bite sensor. Constant, absolute and variable errors were calculated for each outcome and compared between groups using p-values and 95% confidence intervals for effect size (d). Significantly greater degrees of constant, absolute and variable error were seen for force sense testing at the 50% target (p 0.05). Despite this, all joint position sense and force sense measures demonstrated possible clinical significance (upper limits 95% CI d ≥ 0.5). Force sense, particularly at lower levels, appears impaired in those with IA-TMD. Joint position sense and force sense at higher levels appear less affected, although may still be important to consider in the management of IA-TMD in some patients.