IADR Abstract Archives
Electromyographic Activity, Masticatory Force and Mandibular Kinematics During Unilateral Mastication.
Objectives: The aim of the present study is to investigate for the first time sequentially the co-activation of all masticatory muscles of the chewing and non-chewing sides under force-controlled conditions and recording of mandibular kinematics.
Methods: Fourteen healthy participants (seven female), aged between 22-42 years participated at this study. The protocol of the study was approved by the ethics committee of the medical faculty, University of Würzburg (132/16_z-mk).
The activity of all masticatory muscles was recorded bilaterally by means of surface (for masseter, anterior and posterior temporal, and digastric muscles) and intramuscular (medial and lateral pterygoid muscles) electromyography (EMG) during a unilateral (for nine subjects on the right side), force-controlled chewing of elastic and brittle test food (wine jelly and carrot, respectively). Mandibular kinematics were also recorded with a kinesiograph.
Results: The mean total EMG activity (in %MVC) of the measured muscles over the 10 chewing strokes showed higher activity for the jaw adductors. During the first phases of increase in jaw adductor activity, the medial pterygoid showed the highest muscle activity, followed by masseter and the temporal muscles. The EMG activity of the jaw openers (digastric and lateral pterygoid) increased slightly in the last phases of the stroke, and was approximately equal for both muscles, but significantly lower than the EMG activity of the jaw closers. The results of the comparisons between the chewing sides, the sex and between chewing strokes, as well as the influence of the food hardness are largely in agreement with the literature.
Conclusions: This is the first study that has sequentially evaluated all essential parameters of the masticatory act synchronously. This experimental approach allows for validating FEM simulations of the complex masticatory cycle with dynamic data.
Methods: Fourteen healthy participants (seven female), aged between 22-42 years participated at this study. The protocol of the study was approved by the ethics committee of the medical faculty, University of Würzburg (132/16_z-mk).
The activity of all masticatory muscles was recorded bilaterally by means of surface (for masseter, anterior and posterior temporal, and digastric muscles) and intramuscular (medial and lateral pterygoid muscles) electromyography (EMG) during a unilateral (for nine subjects on the right side), force-controlled chewing of elastic and brittle test food (wine jelly and carrot, respectively). Mandibular kinematics were also recorded with a kinesiograph.
Results: The mean total EMG activity (in %MVC) of the measured muscles over the 10 chewing strokes showed higher activity for the jaw adductors. During the first phases of increase in jaw adductor activity, the medial pterygoid showed the highest muscle activity, followed by masseter and the temporal muscles. The EMG activity of the jaw openers (digastric and lateral pterygoid) increased slightly in the last phases of the stroke, and was approximately equal for both muscles, but significantly lower than the EMG activity of the jaw closers. The results of the comparisons between the chewing sides, the sex and between chewing strokes, as well as the influence of the food hardness are largely in agreement with the literature.
Conclusions: This is the first study that has sequentially evaluated all essential parameters of the masticatory act synchronously. This experimental approach allows for validating FEM simulations of the complex masticatory cycle with dynamic data.