Model-based analysis of jaw-movement kinematics using jerk-optimal criterion: simulation of human chewing cycles

Yashiro, Kohtaro; Takada, Kenji

doi:10.1016/j.jelekin.2004.11.005

Cited by 9 publications

(19 citation statements)

References 26 publications

(35 reference statements)

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“…The results thus confirmed the robustness of the current modeling method when applied to those with normal occlusion as well as malocclusions and were basically consistent with previous reports. 13,21 The results of this study suggest that dental malocclusions are likely to impair skillfulness of the masticatory jaw movements. In agreement with a previous study, 22 subjects with malocclusions exhibited a prolonged deceleration phase rather than acceleration and deceleration phases of equal durations in the jawclosing motion, in contrast with the bell-shaped velocity profiles of visually guided arm movements.…”

Section: Discussionmentioning

confidence: 81%

“…A detailed description of the mathematical data processing methods has been reported previously. 13,14 The minimum-jerk model 10,20,21 was applied to the factual jaw displacement trajectory data of the jaw-closing phase for each chewing cycle. The accuracy of the model prediction was measured by using Spearman's correlation coefficient (r) between the actual and predicted velocity profiles.…”

Section: Data Recording and Analysismentioning

confidence: 99%

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Orthodontic Treatment of Malocclusion Improves Impaired Skillfulness of Masticatory Jaw Movements

Tome

Yashiro

Takada

2009

The Angle Orthodontist

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Objective: To investigate whether individuals with malocclusion show less skillfulness, as represented by kinematic parameters that characterize masticatory jaw movement, compared with those having normal occlusion and, if so, to examine whether more skilled movements are achieved after completion of orthodontic treatment. Materials and Methods: Lower incisor point movement in space during gum chewing was recorded, and the kinematic traits of such movement were compared among four subject groups: a Control Group (36 females with good occlusion), a Malocclusion Group (24 females with dental malocclusions), an Extraction Group (31 females who had received orthodontic treatment with premolar extraction) and a Nonextraction Group (27 females who had been treated orthodontically without tooth extraction). Before treatment, all subjects in the three experimental groups exhibited dental malocclusions and skeletal class I jaw-base relationship. Results: Compared with the Malocclusion Group, the lower normalized jerk-cost, the shorter phase durations, the more symmetric property of the velocity profile, and the smaller variance of lateral jaw-closing trajectories near the tooth intercuspation position were determined in the Extraction Group and the Nonextraction Group as well as in the Control Group. Conclusions: As measured by kinematic parameters such as normalized jerk-costs, velocity profile, and variance of movement trajectories near the endpoint of movement, dental malocclusions were associated with significantly lower skillfulness of masticatory jaw motion, whereas good occlusion and orthodontically improved occlusion (either with or without premolar extraction) were both associated with more skillful motion.

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Section: Discussionmentioning

confidence: 81%

Section: Data Recording and Analysismentioning

confidence: 99%

Orthodontic Treatment of Malocclusion Improves Impaired Skillfulness of Masticatory Jaw Movements

Tome

Yashiro

Takada

2009

The Angle Orthodontist

Self Cite

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“…A normalisation technique that generates a measure of jerk cost, which is independent of movement duration ( T ) and amplitude ( D ) (NJC = jerk cost × T 5 / D 2 ), has been proposed. Indices such as NJC, movement time, peak velocity and symmetry of the velocity profile have proved to be effective in explaining the degree of the skilfulness of the human limb and jaw motions .…”

Section: Methodsmentioning

confidence: 99%

“…Smoothness of the jaw movement was quantified using a NJC. A detailed description of the mathematical data processing methods has been reported previously . For the total and decelerative jaw‐closing phases, the NJC and the movement duration [NJC‐all, NJC‐dec, T ‐all (ms) and T ‐dec (ms)] were calculated.…”

Section: Methodsmentioning

confidence: 99%

“…The masticatory jaw movement trajectory of adults with good occlusion is well explained using minimum‐jerk (maximum smoothness) models . Measurements of the normalised jerk cost (NJC) and analyses by minimum‐jerk model simulation have proven to be effective for differentiating between the skilfulness of the chewing cycle performed by subjects with/without malocclusions . It has been demonstrated that the smoothness of masticatory jaw movement in the jaw‐closing phase is impaired for the patients with mandibular prognathism and the impaired skilfulness of the patients results from existence of malocclusal contact between the upper and lower anterior teeth .…”

Section: Introductionmentioning

confidence: 99%

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Improvements in smoothness of chewing cycles in adults with mandibular prognathism after surgery: a longitudinal study

Yashiro

Takada

2013

J of Oral Rehabilitation

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Although adults with mandibular prognathism are known to show impaired smoothness of masticatory jaw movements, it remains uncertain whether/how the surgical-orthodontic treatment is effective to improve masticatory jaw movements. The aims of this study were (i) to verify whether the surgical-orthodontic treatment of patients with mandibular prognathism improve smoothness of the chewing jaw movements post-operatively and, if so, (ii) to examine whether the improved parameters show similar quantities as those of the control subjects. The chewing jaw movements for 13 patients with mandibular prognathism were recorded at pre- and post-treatment stages. The patient group was divided into two groups: Class III(closed) showed full occlusal contact at the habitual intercuspal position, whereas Class III(open) showed inability of occlusal contact between the upper and lower anterior teeth. The control group (CG) consisted of 52 subjects having acceptably good occlusion. The normalised jerk cost (NJC), movement duration and peak velocity in jaw closing were compared. For both Class III(open) and Class III(closed) groups, statistical comparisons revealed that the NJC and movement duration were decreased after the treatment, whereas the peak velocity was increased (all P < 0·01). For the Class III(open), these quantities at the post-treatment stage did not show any significant differences compared with those for the CG. It is concluded that the smoothness of chewing jaw movements for patient with mandibular prognathism were improved after treatment, and for the patients with anterior open bite at pre-treatment, the post-operatively achieved smoothness of jaw-closing movements did not differ from those of the CG.

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Towards modelling of fluid flow and food breakage by the teeth in the oral cavity using smoothed particle hydrodynamics (SPH)

Harrison

Cleary

2013

Eur Food Res Technol

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Model-based analysis of jaw-movement kinematics using jerk-optimal criterion: simulation of human chewing cycles

Cited by 9 publications

References 26 publications

Orthodontic Treatment of Malocclusion Improves Impaired Skillfulness of Masticatory Jaw Movements

Orthodontic Treatment of Malocclusion Improves Impaired Skillfulness of Masticatory Jaw Movements

Improvements in smoothness of chewing cycles in adults with mandibular prognathism after surgery: a longitudinal study

Towards modelling of fluid flow and food breakage by the teeth in the oral cavity using smoothed particle hydrodynamics (SPH)

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