Determination of a pressure pain threshold cut-off value for the diagnosis of temporomandibular joint arthralgia

Abstract

Temporomandibular joint (TMJ) disorders are divided by the American Academy of Orofacial Pain into five categories. The most common ones are joint pain, as arthralgia and joint disorders, as disc displacements. An important clinical presentation of arthralgia is the painful tenderness to manual palpation or decreased pressure pain threshold (PPT). The authors conducted a study to determine the appropriate PPT value to discriminate asymptomatic TMJ individuals from those with moderate to severe arthralgia. Forty-nine individuals was evaluated and divided into groups: TMJ arthralgia, asymptomatic disc displacement and control group. Magnetic resonance images were obtained for all the groups, and algometry was performed on the TMJ lateral pole. Patients with arthralgia filled out a visual analogue scale (VAS). anova test with 1% of significance analysed the data. Specificity, sensitivity and ROC curve were also determined. Arthralgia group had significant lower PPT (mean of 1.07 kgf cm(-2) ) than the others. Asymptomatic disc displacement group (mean of 1.64 kgf cm(-2) ) has shown significant lower PPT than the control (mean of 2.35 kgf cm(-2) ). 89.66% of specificity and 70% of sensitivity were obtained when 1.36 kgf cm(-2) was applied to the TMJ (ROC area = 0.90). This value was considered to be the most appropriate to detected moderate to severe TMJ arthralgia. Indeed, the presence of disc displacement seems to significantly decrease PPT levels in asymptomatic subjects. The PPT value of 1.36 kgf cm(-2) can be used in the calibration procedures of the professionals involved with temporomandibular disorders and orofacial pain.

Keywords: arthralgia; magnetic resonance imaging; pain threshold; sensitivity and specificity; temporomandibular disorders; temporomandibular joint.