Study Of SEMG Variation Of Masticatory Muscles Before And After Restoration In Patients Who Lost The Occlusal Relationship

ObjectiveTo evaluate the effect of the denture and adaption of the patients without the occlusal relationship by investigating the changes in surface electromyography (sEMG) activity of masticatory muscles before and after occlusal rehabilitation and assessing patients'content of the denture.MethodsTwenty patients losing occlusal relationship were selected and conducted with regularly occlusal rehabilitation by full denture or removable partial denture. The sEMG of masseter muscle(MM) and anterior temporalis muscle (TA) at mandibular postural position(MPP) and during clenching at intercuspal position(ICP) were separately recorded in the stage of pretreatment, first wearing,1 week after restoration,1 month after restoration, and long-term observation (more than 3 months). The changes of the mean amplitude(MA) of sEMG, the Asymmetry Indexes(AsI) of bilateral MM, TA and total masticatory muscles(AsMM, AsTA, Astot), Activity Indexes(AcI) of MM/TA in each stage were analyzed. The denture satisfaction was surveyed by questionnaire.Results1. The degree of satisfaction with denture was about 90% at first wearing 1 week later, it dropped to the lowest value. After more than three months using, all the patients were satisfied with the denture.2. The changes in sEMG activity before and after restoration at MPP: â‘ No significant difference was found both in MA and Asl of MM in different stage(P> 0.05).â‘¡After three months using, MA of TA was back to the value in pretreatment (P> 0.05), but significantly higher than 1 week and 1 month after restoration(P< 0.05). Asl of TA was significantly lower than any other stages.â‘¢Acl of MM/TA was negative at every stage, and changed after restoration, but this change was out of statistical significance(P> 0.05).3. The changes in sEMG activity before and after restoration at MPP:â‘ After three months using, MA of MM and TA was significantly increased(P< 0.05). Each Asl was close to first wearing, but significantly lower than 1 week and 1 month after restoration(P< 0.05).â‘¡AcI of MM/TA was close to 0, and didn't have significant change after restoration.Conclusion1. It took some time for patients to adapt the new denture, after 3 months wearing, the effect of denture was largely improved.2. The variation trend of sEMG was corresponded to the variation trend of patient's satisfaction with denture. sEMG can be used to investigate the effect of occlusal rehabilitation and adaption of the masticatory muscles.