title: Model identification of stomatognathic muscle system activity during mastication.
abstract: The present study aimed to determine the numeric projection of the function of the mandible and muscle system during mastication. An experimental study was conducted on a healthy 47 year-old subject. On clinical examination no functional disorders were observed. To evaluate the activity of mastication during muscle functioning, bread cubes and hazelnuts were selected (2 cm2and 1.2/1.3 cm in diameter, respectively) for condyloid processing. An assessment of the activity of mastication during muscle functioning was determined on the basis of numeric calculations conducted with a novel software programme,Kinematics 3D, designed specifically for this study. The efficacy of the model was verified by ensuring the experimentally recorded trajectories were concordant with those calculated numerically. Experimental measurements of the characteristic points of the mandible trajectory were recorded six times. Using the configuration coordinates that were calculated, the dominant componential harmonics of the amplitude-frequency spectrum were identified. The average value of the dominant frequency during mastication of the bread cubes was ~1.16±0.06 Hz, whereas in the case of the hazelnut, this value was nearly two-fold higher at 1.84±0.07 Hz. The most asymmetrical action during mastication was demonstrated to be carried out by the lateral pterygoid muscles, provided that their functioning was not influenced by food consistency. The consistency of the food products had a decisive impact on the frequency of mastication and the number of cycles necessary to grind the food. Model tests on the function of the masticatory organ serve as effective tools since they provide qualitative and quantitative novel information on the functioning of the human masticatory organ.
authors.affiliation: Department of Prosthetic Dentistry, Faculty of Medicine and Dentistry, Pomeranian Medical University, 70-204 Szczecin, Poland.
authors.forename: Edward
authors.initials: E
authors.lastname: Kijak
authors.affiliation: Department of Logistics and Transport, Silesian University of Technology, 44-019 Katowice, Poland.
authors.forename: Jerzy
authors.initials: J
authors.lastname: Margielewicz
authors.affiliation: Department of Propedeutics and Dental Physiodiagnostics, Pomeranian Medical University, 70-204 Szczecin, Poland.
authors.forename: Danuta
authors.initials: D
authors.lastname: Lietz-Kijak
authors.affiliation: School of Public Health in Bytom, Department of Internal Disease, Medical University of Silesia, 40-902 Katowice, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Wilemska-Kucharzewska
authors.affiliation: Institute of Physiotherapy, The Jan Kochanowski University of Humanities and Sciences, 25-317 Kielce, Poland.
authors.forename: Marek
authors.initials: M
authors.lastname: Kucharzewski
authors.affiliation: School of Medicine with the Division of Dentistry in Zabrze, Department of Descriptive and Topographic Anatomy, Medical University of Silesia, 41-808 Zabrze, Poland.
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Śliwiński
keywords: biomechanics; modelling; muscle activity; stomatognathic system