Development and application of reflexodent in the quantitative functional evaluation of chewing control in patients with temporomandibular joint dysfunction and a control group

Background. There has been controversy with respect to the diagnostic value of the inhibitory masseteric reflex in temporomandibular joint dysfunction (TMJD) because the whole reflex response was not considered. The purpose o f this study was to characterize the reflex changes that occur in patients with different levels of TMJD and in a control group. Methods. Eighty-nine patients (ages 31.14 +/- 12.74 years) divided into thr ee groups were studied and compared. The control group was without TMJD (n = 30), with moderate symptoms (n = 30), and with severe symptoms (n = 29), Using an instrument and a software program developed by our group (Reflexod ent), the masseteric inhibitory reflex was studied. The electromyography re cord (EMG) was captured with surface electrodes and the inhibitory reflex w as produced by tapping the chin, The EMG signal was processed, filtered, an d averaged with the Reflexodent. Twenty series of records were applied to e ach patient. The faulty inhibitory area, the area's relation (potentiation/ inhibition) regarding the values of healthy subjects previously characteriz ed, and the bilateral symmetry were measured. Results. Discriminate analysis showed a statistically significant correlati on between clinical groups and electromyographic findings. Statistical func tion explained 91.8% of the discrimination among groups (canonical correlat ion = 0.918, chi(2) = 164.435, p <0.001). Conclusions. The study of whole inhibitory masseteric reflex and the Reflex odent technique are useful as a diagnostic tool to evaluate TMJ illness in the dental clinic. (C) 2000 IMSS. Published by Elsevier Science Inc.