The effects of manual therapy and exercise directed at the cervical spine on pain and pressure pain sensitivity in patients with myofascial temporomandibular disorders

No studies have investigated the effects of the treatments directed at the cervical spine in patients with temporomandibular disorders (TMD). Our aim was to investigate the effects of joint mobilization and exercise directed at the cervical spine on pain intensity and pressure pain sensitivity in the muscles of mastication in patients with TMD. Nineteen patients (14 females), aged 19-57 years, with myofascial TMD were included. All patients received a total of 10 treatment session over a 5-week period (twice per week). Treatment included manual therapy techniques and exercise directed at the cervical spine. Outcome measures included bilateral pressure pain threshold (PPT) levels over the masseter and temporalis muscles, active pain-free mouth opening (mm) and pain (Visual Analogue Scale) and were all assessed pre-intervention, 48 h after the last treatment (post-intervention) and at 12-week follow-up period. Mixed-model anovas were used to examine the effects of the intervention on each outcome measure. Within-group effect sizes were calculated in order to assess clinical effect. The 2 x 3 mixed model anova revealed significant effect for time (F = 77.8; P < 0.001) but not for side (F = 0.2; P = 0.7) for changes in PPT over the masseter muscle and over the temporalis muscle (time: F = 66.8; P < 0.001; side: F = 0.07; P = 0.8). Post hoc revealed significant differences between pre-intervention and both post-intervention and follow-up periods (P < 0.001) but not between post-intervention and follow-up period (P = 0.9) for both muscles. Within-group effect sizes were large (d > 1.0) for both follow-up periods in both muscles. The anova found a significant effect for time (F = 78.6; P < 0.001) for changes in pain intensity and active pain-free mouth opening (F = 17.1; P < 0.001). Significant differences were found between pre-intervention and both post-intervention and follow-up periods (P < 0.001) but not between the post-intervention and follow-up period (P > 0.7). Within-group effect sizes were large (d > 0.8) for both post-intervention and follow-up periods. The application of treatment directed at the cervical spine may be beneficial in decreasing pain intensity, increasing PPTs over the masticatory muscles and an increasing pain-free mouth opening in patients with myofascial TMD.