Electromyographic Activity of Masticatory Muscles in Subjects with Juvenile Idiopathic Arthritis: A Case—Control Study

Abstract

The aim of this study was to evaluate the effect of juvenile idiopathic arthritis (JIA) on the activity of masticatory muscles using surface electromyography (sEMG). Forty-one JIA subjects (ten males, thirty-one females; average age 13 years ± 3) and thirty-two healthy control subjects (twenty-seven females, five males; average age 14 years ± 2) were recruited. sEMG of anterior temporalis (TA), masseter (MM), and sternocleidomastoid (SCM) muscles was performed by using the occlusal contact analyzer software called Teethan (BTS S.p.A., Garbagnate Milanese, Milan, Italy). Comparisons between groups were assessed with unpaired t-tests for non-normally distributed data and with Mann–Whitney U tests for normally distributed parameters. The JIA group showed a significant increased percentage overlapping coefficient of TA (POC TA) (p = 0.01) and impact index (IMP) (p = 0.003). No significant differences were observed for the POC MM, POC SCM, percentage overlapping coefficient between posterior and anterior teeth contact (BAR), the torsion index (TORS), and the asymmetry index (ASIM). Masticatory muscles seemed to be slightly affected by JIA. sEMG could be an effective aid in the early clinical detection of TMJ involvement in JIA. Further research is needed to confirm its validity.

Clinical and Instrumental Temporomandibular Joint Evaluation in Children and Adolescents with Juvenile Idiopathic Arthritis: A Medium-Term Follow-Up

“…The electromyographic results suggest that the masticatory musculature seems to not be involved in the systemic pathology. The significant difference in IMP values between JIA patients and healthy subjects at baseline is confirmed by a previous case-control study conducted by Caroccia et al in 2022, in which the greater muscular activity of the investigated muscles is due to muscular compensation following the joint deficit [42]. Moreover, statistically significant differences in IMP values were found in JIA subjects between baseline and the second examination, showing an improvement in the muscular workload during the clench.…”