Do occlusal splints have an effect on complex regional pain syndrome? A randomized, controlled proof-of-concept trial

Studies have suggested overlaps between various chronic pain conditions and painful temporomandibular disorders (TMDs). The objective of this pilot study was to assess the effectiveness of occlusal splint (OS) therapy on self-reported measures of pain in patients with chronic complex regional pain syndrome (CRPS) as compared with a nontreatment group.

The design was a prospective randomized controlled clinical trial. Twenty patients with CRPS were randomly assigned to either the OS or control group. The patients in the OS group were asked to use the OS at nighttime and for 3 hours during daytime for a total of 7 weeks; the control group had no stomatognathic intervention. The primary outcome was self-reported assessment of CRPS-related pain on numerical rating scales. Secondary outcome measures were the Temporomandibular Index (TMI), and the Short Form 36 Health Survey (SF-36).

All patients had TMD signs and symptoms, but OS had no effect on CRPS-related pain on the numerical rating scale (P>0.100). The changes in the TMI scores over time were 16.6%+/-24.6% (improvement) in the OS group and -21.3%+/-25.9% (impairment) in the control group that was significant (P=0.004). There were no differences in the changes of SF-36 scores between groups (P=0.636).

The use of OS for 7 weeks has no impact on CRPS-related pain but improved signs and symptoms of TMD pain. Future studies should include an active control group and evaluate if long-term changes in measures of oral health impact general health in CRPS-related pain.