Effects of the functional orthopaedic therapy on masticatory muscles activity.

E Di Palma,C Sforza,M Tepedino,Gm Tartaglia,C Chimenti

doi:10.4317/jced.53986

Abstract

BackgroundThe purpose of this study was to examine surface electromyographic (sEMG) activity of masticatory muscles before and after functional orthopaedic therapy with Sander appliance.Material and MethodsTen adolescents (5 girls, 5 boys) with an Angle Class II, division I malocclusion, 9-13 years old, were submitted to sEMG before and after functional orthopaedic therapy. To verify the neuromuscular equilibrium, the standardized EMG activities of right and left masseter and anterior temporal muscles were recorded during maximum voluntary clench, and analysed calculating: POC (index of the symmetric distribution of the muscular activity determined by the occlusion); TC (index of presence of mandibular torque) and Ac (index suggesting the position of occlusal barycentre). The total muscular activity was also calculated. Pre- and post- functional therapy data were compared with Wilcoxon Signed-Rank Test.ResultsBefore treatment, all subjects had a good neuromuscular equilibrium, which was not altered by treatment.ConclusionssEMG evaluations allow to quantify the impact of occlusion on masticatory muscle activity and to control that the functional orthopaedic therapy maintain a good muscular coordination. Key words:Functional appliance, Sander appliance, electromyography, masticatory muscles.

Highlights

The first attempt to study the muscular activity in orthodontics was reported by Moyers [1], who suggested that different patterns of muscular activity seemed to be associated with different types of occlusion
The improvements of muscular activity previously reported were mainly focused on the electrical activity of the muscles, whereas their functional symmetry has not been analysed in detail
If the patient is biting these stainless-steel parts together, they are guided by the inclined plane [16]. -surface electromyographic (sEMG) analysis To evaluate the muscular equilibrium in static conditions, sEMG analysis of right and left masseter and anterior temporalis muscles was performed in all patients before and after functional therapy [14,17,18]

Summary

Introduction

The first attempt to study the muscular activity in orthodontics was reported by Moyers [1], who suggested that different patterns of muscular activity seemed to be associated with different types of occlusion. At the end of the orthopaedic-functional treatment, if the muscles were balanced during a symmetrical contraction, a long lasting stable result is more probable Both the orthopaedic-functional treatment and the orthodontic treatment may cause an altered muscular equilibrium, and in this case the relapse will be a physiological attempt of the stomatognathic system to go back to an acceptable equilibrium [15]. To verify the neuromuscular equilibrium, the standardized EMG activities of right and left masseter and anterior temporal muscles were recorded during maximum voluntary clench, and analysed calculating: POC (index of the symmetric distribution of the muscular activity determined by the occlusion); TC (index of presence of mandibular torque) and Ac (index suggesting the position of occlusal barycentre). Conclusions: sEMG evaluations allow to quantify the impact of occlusion on masticatory muscle activity and to control that the functional orthopaedic therapy maintain a good muscular coordination

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