Occlusal force, electromyographic activity of masticatory muscles and mandibular flexure of subjects with different facial types

William Custodio,Renata Cunha Matheus Rodrigues Garcia,Altair Antoninha Del Bel Cury,Fernanda Faot,Simone Guimarães Farias Gomes

doi:10.1590/s1678-77572011005000008

William Custodio, Renata Cunha Matheus Rodrigues Garcia + Show 3 more

Open Access

https://doi.org/10.1590/s1678-77572011005000008

Copy DOI

Abstract

ObjectiveThe aim of this study was to evaluate whether vertical facial patterns influence maximal occlusal force (MOF), masticatory muscle electromyographic (EMG) activity, and medial mandibular flexure (MMF).Material and MethodsSeventy-eight dentate subjects were divided into 3 groups by Ricketts's analysis: brachyfacial, mesofacial and dolychofacial. Maximum occlusal force in the molar region was bilaterally measured with a force transducer. The electromyographic activities of the masseter and anterior temporal muscles were recorded during maximal voluntary clenching. Medial mandibular flexure was calculated by subtracting the intermolar distance of maximum opening or protrusion from the distance in the rest position. The data were analyzed using ANOVA followed by Tukey's HSD test. The significance level was set at 5%.ResultsData on maximum occlusal force showed that shorter faces had higher occlusal forces (P<0.0001). Brachyfacial subjects presented higher levels of masseter electromyographic activity and medial mandibular flexure, followed by the mesofacial and dolychofacial groups. Additionally, dolychofacial subjects showed significantly lower electromyographic temporalis activities (P<0.05).ConclusionWithin the limitations of the study, it may be concluded that maximum occlusal force, masticatory muscle activity and medial mandibular flexure were influenced by the vertical facial pattern.

Highlights

A variety of craniofacial morphologic features contribute to the determination of vertical facial types in humans19
Previous studies assessing the relationship between mandibular muscles and facial morphology showed that subjects with wider transverse craniofacial dimensions have thicker and stronger mandibular muscles8 and present anatomic features such as small gonial angles25 and reduced lower anterior facial height15
Previous reports have shown the influence of particular craniomorphologic characteristics on muscular activity patterns11,18

Summary

Introduction

A variety of craniofacial morphologic features contribute to the determination of vertical facial types in humans. A variety of craniofacial morphologic features contribute to the determination of vertical facial types in humans19 These facial characteristics can hamper masticatory system functioning. Aside from esthetic considerations, presumed functional muscular activities are IUHTXHQWO\ PHQWLRQHG DV D FDXVH RI PLV¿W RU IDLOXUH in prostheses because muscle actions induce PDQGLEXODU ÀH[XUH DURXQG WKH V\PSK\VLV GXULQJ opening and protrusion movements. Different craniofacial morphologies can lead to differences in neuromuscular activities and in muscle cross-sectional area, volume and orientation. Previous studies assessing the relationship between mandibular muscles and facial morphology showed that subjects with wider transverse craniofacial dimensions have thicker and stronger mandibular muscles and present anatomic features such as small gonial angles and reduced lower anterior facial height. Dolichofacial subjects present weaker muscles than do mesofacial and brachyfacial subjects

Methods

Results

Conclusion