Smoothness of Human Jaw Movement during Chewing

1999 ◽  
Vol 78 (10) ◽  
pp. 1662-1668 ◽  
Author(s):  
K. Yashiro ◽  
T. Yamauchi ◽  
M. Fujii ◽  
K. Takada
Keyword(s):  
Time Profile ◽  
Rate Of Change ◽  
Movement Trajectory ◽  
Jaw Movements ◽  
Jaw Movement ◽  
Movement Trajectories ◽  
Gum Chewing ◽  
Minimum Jerk ◽  
Jaw Opening ◽  
Movement Smoothness

Human limb movements are successfully modeled based on the assumption that the central nervous system controls the movements by maximizing movement smoothness. Movement smoothness is quantified by means of a time integral of squared jerk (jerk-cost), where jerk is defined as the rate of change in acceleration. This study was performed to investigate whether the control of human masticatory vertical jaw movements can also be explained by a minimum-jerk (maximum-smoothness) model. Based on the assumption that minimum-jerk models account for vertical jaw-opening and -closing movements during chewing, the actual time profile of the movement trajectory was simulated by the model. The simulated jerk-costs and peak velocities were compared with those obtained by actual measurements of jaw movements during chewing. Jerk-costs and peak velocities of the jaw movements during chewing were significantly correlated with those predicted by minimum-jerk models (P < 0.0001, r between 0.596 and 0.799). The minimum-jerk models predicted closing movement trajectories more accurately than opening movement trajectories (jaw opening, root-mean-square error = 1.19 mm; jaw closing, 0.52 mm, t = 4.375, P < 0.0001). The results indicated that the vertical jaw movement control during chewing was represented by the minimum-jerk control model and that the vertical jaw-closing movement is smoother than the opening movement during gum-chewing.

Jaw-movement smoothness during empty chewing and gum chewing

2012 ◽  
Vol 120 (3) ◽  
pp. 195-200 ◽  
Author(s):  
Ichiro Minami ◽  
Rahena Akhter ◽  
Julien Luraschi ◽  
Kazuhiro Oogai ◽  
Tetsu Nemoto ◽  
...  
Keyword(s):  
Jaw Movement ◽  
Gum Chewing ◽  
Movement Smoothness

Rotation and Translation of the Jaw During Speech

1990 ◽  
Vol 33 (3) ◽  
pp. 550-562 ◽  
Author(s):  
Jan Edwards ◽  
Katherine S. Harris
Keyword(s):  
Principal Component ◽  
Degree Of Freedom ◽  
Jaw Movements ◽  
Jaw Movement ◽  
The Third ◽  
Body Model ◽  
Jaw Opening ◽  
Rigid Body Model ◽  
Hinge Axis ◽  
Opening And Closing

A two-dimensional rigid-body model of jaw movement was used to describe jaw opening and closing gestures for vowels and for bilabial and alveolar consonants. Jaw movements were decomposed into three components: (a) rotation about the terminal hinge axis, (b) the horizontal translation of that axis, and (c) the vertical translation of that axis. Data were collected for 3 subjects in two separate recording sessions. Multiple regression analysis was used to examine the relationships among the three jaw movement components. For 2 subjects, but not for the third, an interdependence between jaw rotation and the first principal component of jaw translation, horizontal translation, was observed. For these 2 subjects, the first degree of freedom of jaw movement corresponded to a combination of rotation and the first principal component of jaw translation. For the third subject, the first degree of freedom of jaw movement corresponded to rotation alone. The results of this study, like those of Westbury (1988), indicate that an accurate description of jaw movement during speech requires the recording of two points of jaw movement.

Threshold for Detection of Incisal Forces Is Increased by Jaw Movement

2010 ◽  
Vol 89 (4) ◽  
pp. 395-399 ◽  
Author(s):  
P.F Sowman ◽  
R.S.A. Brinkworth ◽  
K.S. Türker
Keyword(s):  
Current Knowledge ◽  
Limb Movement ◽  
Central Incisor ◽  
Jaw Movements ◽  
Detection Thresholds ◽  
Jaw Movement ◽  
Jaw Opening ◽  
Applied Forces ◽  
Opening And Closing

Current knowledge regarding the sensitivity of the teeth to forces is based on psychophysical experiments that measured touch detection thresholds under static jaw conditions. It is not known whether jaw movements alter the perception of forces applied to the teeth, but, based on limb movement studies, it is hypothesized that the perception of mechanoreceptor outputs will be downwardly modulated by jaw movements. We predicted that, compared with static jaw conditions, rhythmic jaw movements would be associated with significantly higher psychophysical thresholds for the detection of incisally applied forces. In eight participants, mechanical pulses were delivered to an incisor during static jaw holding or during cyclic jaw opening and closing. Analogous to findings in human limbs, the psychophysical salience of periodontal mechanoreceptor feedback was downwardly modulated by physiologically relevant movements; detection thresholds for mechanical pulses applied to a central incisor were significantly higher during jaw-closing movements than during static jaw positioning.

Coordination of cortically induced rhythmic jaw and tongue movements in the rabbit

1993 ◽  
Vol 69 (2) ◽  
pp. 569-584 ◽  
Author(s):  
Z. J. Liu ◽  
Y. Masuda ◽  
T. Inoue ◽  
H. Fuchihata ◽  
A. Sumida ◽  
...  
Keyword(s):  
Emg Activity ◽  
Suitable Model ◽  
Rhythmic Movements ◽  
Jaw Movements ◽  
Jaw Movement ◽  
Type D ◽  
Jaw Opening ◽  
Tongue Movements ◽  
Group 2 ◽  
Group 1

1. Rhythmic movements of the jaw, tongue, and hyoid that were induced by stimulation of the cortical masticatory area (CMA) were recorded cineradiographically in the anesthetized rabbit. Jaw movements were also recorded by a laser position detector. 2. The evoked jaw movements were classified into four types: small circular (type A), large circular (type B), large vertical (type C), and crescent-shaped (type D). Among these, types B and D resembled the jaw movements of the food transport cycle and those of the chewing cycle in a masticatory sequence. 3. Each type of jaw movement was associated with a particular pattern of tongue and hyoid movements. In general, the tongue protruded during jaw opening and retracted during jaw closure. The hyoid generally moved upward and forward during jaw opening but downward and backward during jaw closure. 4. Electromyograms (EMGs) were recorded from jaw muscles [masseter (Ma) and digastric (Di) muscles], extrinsic tongue muscles [styloglossus (Sg) and genioglossus (Gg) muscles], and hyoid muscles [sternohyoid (Sh) and geniohyoid (Gh) muscles] during cortically induced rhythmic jaw and tongue movements (CRJTMs). These muscles were classified into two groups: group 1 was activated mainly in the jaw opening phase, and group 2 was activated mainly in the jaw closing and power phases. The Di, Gg, and Gh were included in the former, and the Ma, Sg, and Sh were included in the latter. 5. The timings of EMG activation to a jaw movement cycle were relatively constant for the muscles of group 1, irrespective of the types of CRJTMs, whereas those for the muscles of group 2 altered considerably with the different types of CRJTMs. 6. Relationships of the integrated muscle activity between the Di and Gg and between the Di and Gh were significant, whereas those between the Ma and Sg and between the Ma and Sh were not. 7. When a small strip of polyurethane form of various degrees of hardness was inserted between the opposing molars during CRJTMs, EMG activity of the muscles of group 2 increased with the hardness of the strip. On the other hand, EMG activities of the muscles of group 1 were less affected by the same intraoral stimuli. 8. Two conclusions were reached: first, physiological properties of the CRJTMs and cortically induced rhythmic movements of the hyoid were essentially similar to those observed in natural mastication. This fictive mastication might thus be regarded as a suitable model for simulating natural mastication.(ABSTRACT TRUNCATED AT 400 WORDS)

Reciprocal Interactions between the Rhythmical Jaw Movements and the Jaw Opening Reflex in the Rat

1990 ◽  
Vol 44 (2) ◽  
pp. 440-453 ◽  
Author(s):  
Kazuo Saeki ◽  
Masahiro Ohta ◽  
Satoru Ishizuka ◽  
Makoto Iwasaki
Keyword(s):  
Jaw Movements ◽  
Reciprocal Interactions ◽  
Jaw Opening ◽  
Jaw Opening Reflex

scholarly journals Stability Assessment as a Criterion of Stabilization of the Movement Trajectory of Mobile Crane Working Elements

2018 ◽  
Vol 23 (1) ◽  
pp. 65-77 ◽  
Author(s):  
W. Kacalak ◽  
Z. Budniak ◽  
M. Majewski
Keyword(s):  
Trajectory Optimization ◽  
Assessment Method ◽  
Optimization Criterion ◽  
Movement Trajectory ◽  
Stability Assessment ◽  
Indicator Values ◽  
Movement Trajectories ◽  
Safety Indicator ◽  
Mobile Crane ◽  
The Mathematical Model

AbstractThe article presents a stability assessment method of the mobile crane handling system based on the safety indicator values that were accepted as the trajectory optimization criterion. With the use of the mathematical model built and the model built in the integrated CAD/CAE environment, analyses were conducted of the displacements of the mass centre of the crane system, reactions of the outrigger system, stabilizing and overturning torques that act on the crane as well as the safety indicator values for the given movement trajectories of the crane working elements.

Calculation of Optimized Movement Trajectories for the Human Forearm

2013 ◽  
Vol 401-403 ◽  
pp. 1347-1352
Author(s):  
Li Li Yang
Keyword(s):  
Discrete Time ◽  
Linear Quadratic Regulator ◽  
Minimum Variance ◽  
Movement Trajectory ◽  
Linear Quadratic ◽  
Variance Model ◽  
Movement Trajectories ◽  
Human Forearm ◽  
Optimal Movement ◽  
Time Linear

Using the minimum variance model, optimal human forearm trajectories formation was investigated using a discrete time linear quadratic regulator. First, the continuous dynamics of the human forearm were established on the basis of the relation between muscle torque and neural control signal, and then we transferred the continuous system dynamics to discrete time notation. Finally we expressed the objective function of minimum variance model using a discrete time linear quadratic regulator and employed Riccati recursion to obtain the optimal movement trajectories of the human forearm. The results of example simulation show that the optimal movement trajectory of the forearm follows a smooth curve, and the speed curve of the hand is single peaked and bell shaped. These are in good agreement with the inherent kinematic properties of optimal movement, and therefore the method is effective for calculating the optimal movement trajectory of the human forearm.

Coordination of Tongue Pressure and Jaw Movement in Mastication

2006 ◽  
Vol 85 (2) ◽  
pp. 187-191 ◽  
Author(s):  
K. Hori ◽  
T. Ono ◽  
T. Nokubi
Keyword(s):  
Late Stage ◽  
Healthy Subjects ◽  
Hard Palate ◽  
Early Stage ◽  
Pressure Sensors ◽  
Tongue Pressure ◽  
Normal Pattern ◽  
Jaw Movements ◽  
Jaw Movement ◽  
Palatal Plate

The tongue plays an important role in mastication and swallowing by its contact with the hard palate. Using an experimental palatal plate with 7 pressure sensors, and recording jaw movement using mandibular kinesiography, we assessed, in healthy subjects, the coordination of tongue and jaw movements during the entire masticatory sequence of solids, by measuring tongue pressure against the hard palate. Tongue pressure appeared during the occlusal phase, reached a peak near the start of opening, and disappeared during opening. Specific patterns in order, duration, and magnitude of tongue pressure were seen at the 7 pressure sensors in each chewing stroke. Magnitude and duration were significantly larger in the late stage of chewing (8 strokes before initial swallowing) than in the early stage (until 8 strokes after starting mastication). The normal pattern of tongue contact against the hard palate, control of tongue activity, and coordination with jaw movement during mastication is described.

Tongue Activity During Respiration, Jaw Opening, and Swallowing in Cat

1973 ◽  
Vol 51 (12) ◽  
pp. 1009-1011 ◽  
Author(s):  
Alan A. Lowe ◽  
Barry J. Sessle
Keyword(s):  
Electromyographic Activity ◽  
Jaw Movements ◽  
Physiological Processes ◽  
Jaw Opening ◽  
Tongue Position

Some of the factors involved in the control of tongue position have been investigated. The electromyographic activity reported here provides evidence that genioglossus, the protrusive muscle of the tongue, is under the control of physiological processes associated with respiration, jaw movements, and swallowing. Additional studies are in progress to define further the neutral mechanisms underlying these effects.

scholarly journals Development of 2-D Jaw Movement Simulator (JSN/S1)

1998 ◽  
Vol 10 (6) ◽  
pp. 499-504 ◽  
Author(s):  
Shin-ichi Nakajima ◽  
◽  
Toyohiko Hayashi ◽  
Hiroshi Kobayashi ◽  
◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Sagittal Plane ◽  
Jaw Movements ◽  
Occlusal Force ◽  
Neural Network Learning ◽  
Jaw Movement ◽  
Network Learning ◽  
Control Scheme ◽  
Muscle Actuators ◽  
Dc Servomotor

Human mastication is performed by coordinated activities of several jaw muscles. To clarify functions of these muscles, we developed a jaw movement simulator (JSN/Sl) consisting of a 2 degrees of freedom (2DOF) mechanism and five muscle actuators able to reproduce jaw movements on a sagittal plane. The actuator is a cable-tendon driven by a DC servomotor controlled by a compliance control scheme to obtain viscoelastic muscle characteristics. To simulate life-like clenching, we controlled occlusal position and force by incorporating position and force sensors, using neural network learning control. Occlusal force successfully converged to a desired value through learning. Tension patterns of muscle actuators during clenching well coincided with human jaw activities.

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