[Effects of orthodontic treatment on the masseter muscle inhibitory reflex].
OBJECTIVE
The aim of this study was to identify the effect of the orthodontic treatment on inhibitory masseteric reflex.


METHODS
Twenty-three patients with any type of malocclusion and without any temporomandibular joint dysfunction were studied and treated under arch wire technique with Roth's brackets prescription (0.22" x 0.28"). Electromyographic record of the inhibitory masseteric reflex was obtained before and after orthodontic treatment.


RESULTS
ANOVA test identified not reflex differences between molar relation types; using Student t test for paired data it was identified that with orthodontic treatment (14.65 +/- 2.40 months), the left reflex latency was increased from 6.17 +/- 9.29 ms to 37.00 +/- 66.33 ms (p < 0.05). However the left inhibition duration was decreased from 57.78 +/- 30.70 ms to 35.31 +/- 25.72 ms (p < 0.05), the right inhibition amplitude was decreased from 48.40 +/- 34.44 mV to 28.59 +/- 17.26 mV (p < 0.05) and the left inhibition amplitude was decreased from 40.72 +/- 29.75 mV to 18.73 +/- 17.68 mV (p < 0.05).


CONCLUSIONS
Orthodontic treatment produced constraint of the masseter inhibitory capacity, which could be a transitory neuromuscular adaptation signal in the presence of sensorial scheme modifications. It is necessary to wait for a longer period of time before a new register to clarify the reflex morphology tendency.
D000293:Adolescent; D000328:Adult; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008310:Malocclusion / Q000503:physiopathology / Q000628:therapy; D008406:Masseter Muscle / Q000503:physiopathology*; D016910:Orthodontic Brackets / Q000009:adverse effects; D009969:Orthodontic Wires / Q000009:adverse effects*; D012021:Reflex, Abnormal