Abstract: Objective: To analyze the masticatory muscle electromyographic activity in generalized aggressive periodontitis (GagP) patients. Methods: The electromaography of anterior temporalis (TA), masseter muscle (MM), digastric anterior (DA) and sternocleidomastiod (SCM) were recorded in differential mandibular positions. The electromaography (EMG) was analyzed using bundled software. Results:In the resting position, the electromyography values of anterior temporalis, masseter muscle, digastric anterior and sternocleidomastiod of periodontitis group were higher than those of the control group. In the intercuspal position, the electromyography values of anterior temporalis, masseter muscle of periodontitis group were lower than those of control group (P＜0.001). In the resting position, anterior temporalis, masseter muscle, digastric anterior and sternocleidomastiod of periodontitis group showed low electromyographic activities, TA＞MM＞DA. In the intercuspal position, TA＞MM;In the protrusive position, DA＞MM＞TA;In the retruded contact position, DA＞MM,TA＞MM. The differences were statistically significant (P＜0.05). In the intercuspal position, the asymmetry index of electromyography values of anterior cntemporalis, masseter muscle of periodontitis group were lower than those of the control group(P＜0.05). Conclusion: The masticatory function of the patients with GagP was impaired by the damaged periodontium. The patients with GagP showed unbalanced chewing activity, muscle dysfunction and masticatory muscle tension imbalance in left and right side.

Key words: Generalized aggressive periodontitis, Masticatory muscle , Electromaography