Topical versus systemic diclofenac in the treatment of temporo-mandibular joint dysfunction symptoms

The most frequent symptom of craniomandibular dysfunction is pain in the preauricular area or in the temporo-mandibular joint, usually localized at the level of the masticatory musculature. Patients sometimes also complain of reflect otalgia, headaches and facial pain. Osteoarthrosis is a frequent degenerative debilitating chronic disorder that can affect the temporomandibular joint. It causes pain and articular rigidity, a reduction in mobility, and radiological alterations are visible in stratigraphy. The aim of this study was to compare the efficacy of a topically applied non-steroid anti-inflammatory drug that has recently become commercially available (diclofenac sodium in a patented carrier containing dimethyl sulfoxide, that favours transcutaneous absorption) which is commonly used to alleviate pain in knee or elbow joints, versus oral diclofenac, in the treatment of symptoms of temporomandibular joint dysfunction. Dysfunction of the temporomandibular joint was diagnosed in 36 adult patients. The patients were randomized in two age- and gender -matched groups. Group A (18 patients) received oral diclofenac sodium administered after a meal in 50-mg tablets twice a day for 14 days. Group B (18 patients) received 16 mg/ml topical diclofenac (diclofenac topical solution, 10 drops 4 times a day for 14 days). All patients completed a questionnaire at the start and end of therapy. Patients were asked to quantify on a graded visual analogue scale and to reply to questions about the pain and tenderness of the temporomandibular joint and the functional limitation of mouth opening. Patients were also requested to report side-effects of the treatment. All patients showed relief from pain after treatment: the difference between the two groups was not significant (p > 0.05). Post-treatment, 16 patients of group A had epigastralgic symptoms. Three patients treated with topical diclofenac showed a modest irritation of the temporomandibular joint region, and disappeared spontaneously. Our results demonstrate that topically applied diclofenac and oral diclofenac are equally effective in the treatment of temporomandibular joint dysfunction symptoms. Topical diclofenac has the advantage that it does not have adverse systemic effects, whereas oral diclofenac had untoward effects on the gastric apparatus. The efficacy of diclofenac topically applied on the temporomandibular joint region observed in group B is explained by the association of diclofenac with dimethyl-sulfoxide, which enables a rapid effective penetration into the joint tissues. It is noteworthy that dimethyl-sulfoxide favours transuctaneous absorption when used in a multi-dose regime as in our study with 4 doses a day. Thus, single, "as required", applications should be avoided because this practice results in scarce absorption of diclofenac.