Temporomandibular joint (TMJ) involvement is common in juvenile idiopathic arthritis (JIA). Dexamethasone iontophoresis (DIP) uses low-grade electric currents for transdermal dexamethasone delivery into deeper anatomic structures. The purpose of this study was to assess the safety and effectiveness of DIP for the treatment of TMJ involvement in JIA, and to delineate variables that are associated with improvement after DIP.
Medical records of all JIA patients who underwent DIP for TMJ involvement at a larger tertiary pediatric rheumatology center from 1997-2011 were reviewed. DIP was performed using a standard protocol. The effectiveness of DIP was assessed by comparing the maximal interincisor opening (MIO(TMJ) ) and the maximal lateral excursion (MLE(TMJ) ) before and after treatment.
Twenty-eight patients (ages 2-21 years) who received an average of 8 DIP treatment sessions per involved TMJ were included in the analysis. Statistically significant improvement in the median MIO(TMJ)  (P < 0.0001) was observed in 68%. The median MLE(TMJ)  (P = 0.03) improved in 69%, and resolution of TMJ pain occurred in 73% of the patients who had TMJ pain at baseline. Side effects of DIP were transient site erythema (86%), skin blister (4%), and metallic taste (4%). Improvement in TMJ range of motion from DIP is associated with lower MIO(TMJ) , lower MLE(TMJ) , and absence of TMJ crepitus at baseline.
In this pilot study, DIP appeared to be an effective and safe initial treatment of TMJ involvement in JIA, especially among patients with decreased TMJ measurements. Prospective controlled studies are needed.