Objective: To examine whether asymmetry in the area of occlusal contact and near contact (ACNC) and asymmetrical masticatory muscle electromyographic activity are correlated in healthy dentate adults.Methods: Ninety-one healthy subjects with full dentition were included. Seven levels of ACNC were registered, and the asymmetry indexes (AsI) for each level of ACNC (AsI-ACNC) were determined. Surface EMG was used to record bilateral anterior temporalis activity and masseter muscle activity. The AsI for the anterior temporalis, masseter, and the combination of both muscles were calculated.Results: Pearson's correlation analysis revealed all levels of AsI-ACNC were significantly, negatively correlated with the AsI of the anterior temporalis and the combination of both muscles (p < 0.05), but not the AsI of the masseter muscle (p > 0.05).Conclusion: The side with greater ACNC has significantly lower anterior temporalis activity and combined anterior temporalis and masseter muscle activity on the ipsilateral side.
Keywords: Masticatory muscles; dental occlusion; dentition; electromyography; masseter muscle; temporal muscle.