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Chewing Stroke (chewing + stroke)

Distribution by Scientific Domains

Medical Sciences	60%

Selected Abstracts

Buccal and lingual activity during mastication and swallowing in typical adults

JOURNAL OF ORAL REHABILITATION, Issue 1 2003
M. J. Casas
summary, A non-invasive protocol was developed to assess tongue and cheek movements during mastication and to evaluate the temporal relationship between mastication and the initiation of pharyngeal swallowing. Typical adults (three males and three females) were monitored during chewing. Miniature pressure transducers were bonded unilaterally to the buccal and lingual surfaces of the first mandibular molar and the buccal surface of the first maxillary molar on each subject's preferred chewing side. Surface electromyography of the ipsilateral masseter muscle was recorded as an indicator of jaw-closing activity. Pressure and electromyography (EMG) recordings were time-linked to simultaneous B-mode ultrasound imaging of the oral cavity using a submental, coronal view aligned with the first mandibular molar. The intervals between peak pressure recorded at each pressure transducer and peak jaw-closing activity for each masticatory cycle were not statistically different [analysis of variance (anova), P=0·9856] and displayed large statistical variation. These intervals were not different at the beginning of the trials (hard biscuit) than they were at the completion of mastication when the cookie had been broken down to a paste/puree consistency bolus. The interval between the last chewing stroke and the initiation of swallowing was 0·92 ± 0·34 s). No significant difference existed among subjects for this time interval (anova, P=0·382). [source]

Enamel ridge alignment in upper molars of ruminants in relation to their natural diet

JOURNAL OF ZOOLOGY, Issue 1 2010
T. M. Kaiser
Abstract Although it is generally thought that dental design reflects mechanical adaptations to particular diets, concrete concepts of such adaptations beyond the evolution of hypsodonty are largely missing. We investigated the alignment of enamel ridges in the occlusal molar surface of 37 ruminant species and tested for correlations with the percentage of grass in the natural diet. Independent of phylogenetic lineage, species that were either larger and/or included more grass in their natural diet showed a higher proportion of enamel ridges aligned at low angles to the direction of the chewing stroke. Possible explanations for this design are a potential alignment of grass blades in parallel to the molar tooth row, a potential increased proportion of a propalinal (anterior,posterior) chewing movement in grazers as opposed to a strictly transversal chewing stroke in browsers and the general distribution of forces along the occlusal surface during the chewing stroke. The latter will be less heterogenous (with less force peaks) with an increasing proportion of low-angle enamel ridges. While the validity of these explanations will have to be tested in further studies, the enamel ridge alignment represents a clear signal that deviates from an arbitrary distribution and hence most likely represents a functional adaptation. [source]

Masticatory performance in patients with anterior disk displacement without reduction in comparison with symptom-free volunteers

EUROPEAN JOURNAL OF ORAL SCIENCES, Issue 5 2002
Ingrid Peroz
Masticatory function can be impaired by craniomandibular disorders. The aim of this study was to assess masticatory performance in patients with an anterior disc displacement (ADD) without reduction. In the experiments, 29 patients and 33 age- and gender-matched volunteers chewed artificial test food for 60 chewing strokes. The collected remains of the test food were filtered, dried, fractionated by a sieving procedure, and weighed. The particle size distribution was then described using a cumulative distribution function. Patients and controls were clinically examined, and patients were asked to complete a pain questionnaire. Comparison with controls, patients showed significantly reduced masticatory performance. Patients that had had a disorder longer than 3 yr tended to display less reduction of their masticatory performance. Neither the treatment methods used, nor restriction of daily life activities or pain intensity were significantly correlated with masticatory performance. Jaw mobility was significantly reduced in patients. More than half of the patients and none of the controls had joint noises and trigger points in the masticatory muscles. Pain was present, in particular, during chewing and maximal opening of the mouth. It was concluded that patients with ADD without reduction have a significantly reduced masticatory performance. [source]

The role of oral sensorimotor function in masticatory ability

JOURNAL OF ORAL REHABILITATION, Issue 3 2004
K. Hirano
summary, In order to investigate the relationship between oral sensorimotor ability and masticatory function, an oral stereognosis ability (OSA) test, masticatory performance and efficiency was employed for 15 dentate subjects. Subjects were instructed to orally identify OSA test pieces blindly. The response score and sum of the duration time for identification were used for analysis as OSA score and OSA response time. Masticatory function was evaluated using a sieving method with 3 g of peanuts. Masticatory performance was calculated with the weight percentage of portions finer than 1700 ,m by the total volume after 20 chewing strokes. Masticatory efficiency was calculated by the declination rate of median particle size which is defined by the Rosin,Rammler equation. To analyse the relationship between OSA variables and masticatory ability, the correlation coefficient was calculated. The results summarized as a significant correlation was found only between OSA score and masticatory efficiency. However, a significant correlation could not be found between other OAS variables and masticatory ability. It was revealed that positive correlation existed between oral stereognosis ability and masticatory ability. It was suggested that the role of oral sensorimotor function might affect the masticatory function. [source]