Improvement in Smoothness of the Chewing Cycle Following Treatment of Anterior Crossbite Malocclusion: A Case Report

Yashiro, Kohtaro; Miyawaki, Shouichi; Tome, Wakako; Yasuda, Yoshitaka; Takada, Kenji

doi:10.1179/crn.2004.020

Cited by 15 publications

(21 citation statements)

References 15 publications

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“…Such graphical representations of jerk‐cost may help clinical practitioners to visualize and better understand changes of smoothness in their patients’ mandibular movements during chewing. Previous studies reported evaluations of movement smoothness in mastication calculated jerk‐cost using normalized units of time and 3D pathway length (4–9); these methods were used to avoid introducing calculation errors through multiple differentiations. This normalization, however, prohibited the accurate measurement of the momentary jerk and jerk‐cost associated with discrete masticatory phases.…”

Section: Discussionmentioning

confidence: 99%

“…A previous study reported the utility of jerk‐cost measurements in the evaluation of masticatory movement and indicated a strong correlation between occlusal integrity and jerk‐cost (4). Other studies have shown that the jerk‐cost of the jaw movement during chewing is improved by the placement of prosthetic restorations (5, 6) and orthodontic treatments (7–9). It is expected, therefore, that the jerk‐cost as a measure of jaw movement smoothness may be used to evaluate the masticatory function of patients with tooth loss and malocclusion.…”

Section: Introductionmentioning

confidence: 99%

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Measurement of jerk-cost using a triaxial piezoelectric accelerometer for the evaluation of jaw movement smoothness

Minami

Nemoto

Nakamura

et al. 2010

Journal of Oral Rehabilitation

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Jerk-cost as a measure of jaw movement smoothness has been used to evaluate the masticatory function of patients with tooth loss and malocclusion. Jerk-cost measuring systems have thus far been unable to determine the jerk-cost of each chewing phase over time. The purposes of this study were (i) to develop a new method for measuring momentary jerk-cost of the jaw movement using a small triaxial piezoelectric accelerometer and (ii) to test the hypothesis that the lowest smoothness is seen during jaw-opening phase. The accelerometer was attached to the skin of the mentum of each subject. Vertical jaw displacement, acceleration, the jerk, and the time differential of jerk-cost during gum chewing were analysed as a function of time in five normal dentate subjects (n = 5). The system revealed intra-class correlation coefficients of intra-examiner, inter-examiner, and test-retest consistency of substantially high values (0.80-0.88). In all subjects, the highest jerk-cost was observed in the opening phase of each chewing cycle when the gum was parting from the teeth; the lowest jerk-cost was observed in the intercuspal phase throughout the chewing cycle, thus confirming the hypothesis. Significant differences were observed between the opening, closing, and intercuspal chewing phases (N = 5, P = 0.007). The smoothness measurement system used in this study evaluated the momentary smoothness of each chewing phase in the masticatory cycle. The system may serve as a diagnostic tool to evaluate the smoothness of the jaw movement in general dental practice.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Measurement of jerk-cost using a triaxial piezoelectric accelerometer for the evaluation of jaw movement smoothness

Minami

Nemoto

Nakamura

et al. 2010

Journal of Oral Rehabilitation

View full text Add to dashboard Cite

show abstract

“…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%

“…In general, a lower jerk cost indicates smooth movement having lesser tremulous motor segments inefficiently driven by rapid acceleration or deceleration. It has been reported that the kinematic parameters such as jerk cost and velocity profile indicate smoothness of jaw movements .…”

Section: Introductionmentioning

confidence: 99%

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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“…A recent case report 24 , using the current kinematic parameters, has documented improved masticatory jaw function as a result of progress in orthodontic treatment. In agreement with this, the morphologically improved occlusal state achieved as a result of orthodontic treatment was found to provide kinematically optimized masticatory jaw motion that was more skillful than that seen in individuals with untreated malocclusions.…”

Section: Discussionmentioning

confidence: 99%

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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Improvement in Smoothness of the Chewing Cycle Following Treatment of Anterior Crossbite Malocclusion: A Case Report

Cited by 15 publications

References 15 publications

Measurement of jerk-cost using a triaxial piezoelectric accelerometer for the evaluation of jaw movement smoothness

Measurement of jerk-cost using a triaxial piezoelectric accelerometer for the evaluation of jaw movement smoothness

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

Orthodontic Treatment of Malocclusion Improves Impaired Skillfulness of Masticatory Jaw Movements

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