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Dental Materials : Official Publication... Jan 2018Occlusal loading during clenching and biting is achieved by the action of the masticatory system, and forms the basis for the evaluation of the functional performance of... (Review)
Review
OBJECTIVES
Occlusal loading during clenching and biting is achieved by the action of the masticatory system, and forms the basis for the evaluation of the functional performance of prosthodontic and maxillofacial components. This review provides an overview of (i) current bite force measurement techniques and their limitations and (ii) the use of computational modelling to predict bite force. A brief simulation study highlighting the challenges of current computational dental models is also presented.
METHODS
Appropriate studies were used to highlight the development and current bite force measurement methodologies and state-of-the-art simulation for computing bite forces using biomechanical models.
RESULTS
While a number of strategies have been developed to measure occlusal forces in three-dimensions, the use of strain-gauges, piezo-electric sensors and pressure sheets remain the most widespread. In addition to experimental-based measurement techniques, bite force may be also estimated using computational models of the masticatory system. Simulations of different bite force models clearly show that the use of three-dimensional force measurements enriches the evaluation of masticatory functional performance.
SIGNIFICANCE
Hence, combining computational modelling with three-dimensional force measurement techniques can significantly improve the evaluation of masticatory system and the functional performance of prosthodontic components.
Topics: Biomechanical Phenomena; Bite Force; Computer Simulation; Dental Occlusion; Dental Stress Analysis; Humans; Mastication; Models, Dental
PubMed: 29017762
DOI: 10.1016/j.dental.2017.09.005 -
Brain and Nerve = Shinkei Kenkyu No... Feb 2015Abstract Comminution of food by mastication contributes to an increase in the efficiency of energy intake from food, which supports the high metabolic rate of mammals.... (Review)
Review
Abstract Comminution of food by mastication contributes to an increase in the efficiency of energy intake from food, which supports the high metabolic rate of mammals. The central pattern-generating circuit for mastication produces motor commands for mastication by using sensory information from periodontal mechanoreceptors and muscle spindles in the jaw-closing muscles. The motor commands that are glutamatergic, glycinergic, and GABAergic are transmitted to motoneurons for the jaw, tongue, etc., through premotor neurons that are located in the supratrigeminal region, reticular formation dorsal to the facial nucleus, etc. Our previous studies of N-methyl-D-aspartate-induced fictive suckling using isolated brainstem-spinal cord preparations obtained from neonatal mice revealed that the neuronal network that contributes to the synchronized activity of the jaw and tongue muscles is located in both the right and left sides. The network of either side sends its command to the trigeminal motoneurons mainly via the commissural pathway, while the command is sent to the hypoglossal motoneurons on the same side.
Topics: Animals; Brain Stem; Humans; Jaw; Mastication; Motor Neurons; Muscle, Skeletal; Nerve Net
PubMed: 25681360
DOI: 10.11477/mf.1416200107 -
Physiology & Behavior May 2018There is a growing body of literature which suggests that oral health and mastication can influence cognitive and systemic health during aging. However, it is currently... (Review)
Review
There is a growing body of literature which suggests that oral health and mastication can influence cognitive and systemic health during aging. However, it is currently unclear whether oral health, masticatory efficiency, cognitive health and systemic health merely deteriorate independently with age, or whether mechanisms exist linking mastication to cognitive and systemic health directly. The aim of this paper is to review the extent to which reduced mastication influences cognitive and systemic health during aging because this knowledge may underpin future interventions that improve quality of life. Current evidence suggests that a deterioration in mastication and oral health during aging can have: 1) direct effects on systemic health through mechanisms such as the migration of the oral microbiota into the systemic environment, and 2) indirect effects on systemic health through changes nutrient intake. A loss of teeth and reduction in masticatory efficiency during aging can have: 1) direct effects on cognitive performance and potentially impact cognitive health through mechanisms such as enhanced adult hippocampal neurogenesis, and 2) indirect effects on cognitive health through changes in nutrient intake. It is concluded that oral health and masticatory efficiency are modifiable factors which influence the risk poor cognitive and systemic health during aging, although it is currently premature to propose chewing-based interventions to slow the rate of cognitive decline and improve cognitive health during aging. Future research should include large-scale longitudinal studies which control for the types of confounding factors which concurrently influence the association between mastication and cognitive and systemic health.
Topics: Aging; Cognition; Cognition Disorders; Feeding and Eating Disorders; Humans; Mastication
PubMed: 29452151
DOI: 10.1016/j.physbeh.2018.02.018 -
BMC Oral Health Mar 2022Previous masticatory studies have focused on a variety of measurements of foods and boluses or kinematic parameters and sound during mastication. To date, the...
BACKGROUND
Previous masticatory studies have focused on a variety of measurements of foods and boluses or kinematic parameters and sound during mastication. To date, the masticatory sound research of has been limited due to the difficulties of sound collection and accurate analysis. Therefore, significant progress in masticatory sound has not been made. Meanwhile, the correlation between acoustic parameters and mastication performance remains unclear. For the purpose of exploring the acoustic parameters in measuring mastication performance, the bone-conduction techniques and sound analysis were used, and a statistical analysis of acoustic and occlusal parameters were conducted.
METHODS
The gnathosonic and chewing sounds of fifty-six volunteers with healthy dentate were recorded by a bone-conduction microphone and further analyzed by Praat 5.4.04 when intercuspally occluding natural foods (peanuts) were consumed. The granulometry of the expectorated boluses from the peanuts was characterized by the median particle size of the whole chewing sequence (D50) and the median particle size during the fixed chewing strokes (D50). The chewing time of the whole chewing sequence (CT), the chewing time of the fixed chewing strokes (CT), the chewing cycles (CC), and the chewing frequency (CF) were recorded and analyzed by the acoustic software. The acoustic parameters, including gnathosonic pitch, gnathosonic intensity, mastication sound pitch of the whole chewing sequence (MP), mastication sound pitch of the fixed chewing strokes (MP), mastication sound intensity of the whole chewing sequence (MI) and mastication sound intensity of the fixed chewing strokes (MI), were analyzed. Independent sample t-test, Spearman and Pearson correlation analyses were used where applicable.
RESULTS
Significant difference in parameters CC, MI, CF and D50 were found by sex (t-test, p < 0.01). The masticatory degree of the test foods was higher in women (CC, 24.25 ± 5.23; CF, 1.70 ± 0.21 s; D50, 1655.07 ± 346.21 μm) than in men (CC, 18.14 ± 6.38; CF, 1.48 ± 0.18 s; D50, 2159.21 ± 441.26 μm). In the whole chewing sequence study, a highly negative correlation was found between MI and D50, and a highly positive correlation was found between MI and CF (r = - 0.94, r = 0.82, respectively, p < 0.01). No significant correlation was found between the remaining acoustic parameters and mastication parameters. In the fixed chewing strokes study, a highly negative correlation was found between MI and D50 (r = - 0.85, p < 0.01). There was no significant correlation between the rest of the acoustic parameters and the mastication parameters.
CONCLUSIONS
Mastication sound intensity may be a valuable indicator for assessing mastication. Acoustic analysis can provide a more convenient and quick method of assessing mastication performance.
Topics: Acoustics; Biomechanical Phenomena; Female; Food; Humans; Male; Mastication; Particle Size
PubMed: 35291996
DOI: 10.1186/s12903-021-02018-9 -
The International Journal of... 2014
Topics: Age Factors; Aged; Aged, 80 and over; Cerebrovascular Circulation; Cognition; Dental Occlusion; Dentition; Female; Hippocampus; Humans; Hydrocortisone; Male; Mastication; Middle Aged; Sex Factors
PubMed: 25191880
DOI: 10.11607/ijp.2014.5.e -
Gerodontology Jun 2023The present systematic review and meta-analysis aimed to summarise the current information on the masticatory function of stroke patients. (Meta-Analysis)
Meta-Analysis Review
PURPOSE
The present systematic review and meta-analysis aimed to summarise the current information on the masticatory function of stroke patients.
METHODS
Four electronic databases (Medline, Embase, CINAHL and Web of Science) were searched for relevant observational studies and clinical trials (up to Jun 2021) on the masticatory function of stroke patients. Two reviewers independently performed study selection and quality assessments (using JBI Critical Appraisal Checklist). Meta-analysis was conducted for the comparison of bite force and masticatory performance using standardised mean difference (SMD). Of the 3837 records identified, nine studies, corresponding to 11 papers and 302 participants, were included in the analysis.
RESULTS
The maximum bite force of stroke patients was significantly lower than that of the healthy individuals (SMD -0.52, 95% CI: -0.95 to -0.08, P = .02). There was no significant difference between the ipsi-lesional and the contra-lesional sides of the same stroke patient (SMD 0.13, 95% CI: -0.14 to 0.39, P = .34). Stroke patients had lower masticatory performance than healthy people (SMD -0.97, 95% CI: 0.57 to 1.37, P < .00001), and the contra-lesional side was worse than the ipsi-lesional side. Electromyographic analysis indicated that muscle activation of stroke patients was poorer than the healthy individuals, and stroke patients seem to exhibit dysfunction in the recruiting and firing of motor units.
CONCLUSIONS
Stroke patients have lower maximum bite force and masticatory performance than healthy people, with masticatory performance being the most affected.
Topics: Humans; Stroke; Stroke Rehabilitation; Bite Force; Masticatory Muscles; Mastication
PubMed: 36004768
DOI: 10.1111/ger.12653 -
Archives of Oral Biology Jun 2017This critical review summarizes the current knowledge of the structural and functional characteristics of periodontal mechanoreceptors, and understands their role in the... (Review)
Review
PURPOSE
This critical review summarizes the current knowledge of the structural and functional characteristics of periodontal mechanoreceptors, and understands their role in the signal pathways and functional motor control.
METHOD
A systematic review of the literature was conducted. Original articles were searched through Pubmed, Cochrane Central database and Embase until january 2016.
RESULT
1466 articles were identified through database searching and screened by reviewing the abstracts. 160 full-text were assessed for eligibility, and after 109 exclusion, 51 articles were included in the review process. Studies selected by the review process were mainly divided in studies on animal and studies on humans. Morphological, histological, molecular and electrophysiological studies investigating the periodontal mechanoreceptors in animals and in humans were included, evaluated and described.
CONCLUSION
Our knowledge of the periodontal mechanoreceptors, let us conclude that they are very refined neural receptors, deeply involved in the activation and coordination of the masticatory muscles during function. Strictly linked to the rigid structure of the teeth, they determine all the functional physiological and pathological processes of the stomatognathic system. The knowledge of their complex features is fundamental for all dental professionists. Further investigations are of utmost importance for guiding the technological advances in the respect of the neural control in the dental field.
Topics: Animals; Humans; Mastication; Masticatory Muscles; Mechanoreceptors; Periodontium; Stress, Mechanical
PubMed: 28226300
DOI: 10.1016/j.archoralbio.2017.02.010 -
Experimental Gerontology Apr 2019Aging rodent models allow for the discovery of underlying mechanisms of cranial muscle dysfunction. Methods are needed to allow quantification of complex, multivariate...
BACKGROUND
Aging rodent models allow for the discovery of underlying mechanisms of cranial muscle dysfunction. Methods are needed to allow quantification of complex, multivariate biomechanical movements during swallowing. Videofluoroscopic swallow studies (VSS) are the standard of care in assessment of swallowing disorders in patients and validated quantitative, kinematic, and morphometric analysis methods have been developed. Our purpose was to adapt validated morphometric techniques to the rodent to computationally analyze swallowing dysfunction in the aging rodent.
METHODS
VSS, quantitative analyses (bolus area, bolus velocity, mastication rate) and a rodent specific multivariate, morphometric computational analysis of swallowing biomechanics were performed on 20 swallows from 5 young adult and 5 old Fischer 344/Brown Norway rats. Eight anatomical landmarks were used to track the relative change in position of skeletal levers (cranial base, vertebral column, mandible) and soft tissue landmarks (upper esophageal sphincter, base of tongue).
RESULTS
Bolus area significantly increased and mastication rate significantly decreased with age. Aging accounted for 77.1% of the variance in swallow biomechanics, and 18.7% of the variance was associated with swallow phase (oral vs pharyngeal). Post hoc analyses identified age-related alterations in tongue base retraction, mastication, and head posture during the swallow.
CONCLUSION
Geometric morphometric analysis of rodent swallows suggests that swallow biomechanics are altered with age. When used in combination with biological assays of age-related adaptations in neuromuscular systems, this multivariate analysis may increase our understanding of underlying musculoskeletal dysfunction that contributes to swallowing disorders with aging.
Topics: Aging; Animals; Biomechanical Phenomena; Deglutition; Deglutition Disorders; Fluoroscopy; Image Processing, Computer-Assisted; Mastication; Models, Animal; Rats; Video Recording
PubMed: 30633957
DOI: 10.1016/j.exger.2019.01.006 -
CoDAS 2022To present the Myofunctional Orofacial Clinical Examination Protocol belonging to the MMBGR Protocol - Infants and Preschoolers, including its validation.
PURPOSE
To present the Myofunctional Orofacial Clinical Examination Protocol belonging to the MMBGR Protocol - Infants and Preschoolers, including its validation.
METHODS
Initially, test content-based validity was evaluated from the MBGR Protocol to be used with the age group between 6 and 71 months based on the bibliography and experience between the authors (original and current). For the content and appearance analysis, 10 speech therapists specialized in Orofacial Motricity attended and filled out an electronic form with dichotic and Likert scale questions in two moments. We used the Content Validity Index and the Exact Binomial Test. Then there was a validity based on the response processes analysis followed by a reliability of the Clinical Examination with 155 participants by 7 experienced and calibrated speech therapists, and the examiners between and within agreement was verified by the Intraclass Correlation Coefficient.
RESULTS
There were additions, modifications, and exclusions of items according to the age group, resulting in the Myofunctional Orofacial Clinical Examination Protocol for Infants and Preschoolers, which obtained 90.5% agreement; and 100% of the appropriate scores by at least 90% of the specialists. In reliability, most items of the Extraoral and Intraoral Examination and Chewing obtained a reasonable to good, or even excellent, agreement.
CONCLUSION
The "Clinical Myofunctional Clinical Examination" was validated based on the test content, response process, and reliability and, along with the "Instructional" and the "Clinical History" is part of the "MMBGR Protocol - Infants and Preschoolers" for speech therapy activities in the age group between 6 and 71 months of age.
Topics: Child, Preschool; Clinical Protocols; Humans; Infant; Mastication; Reproducibility of Results
PubMed: 35475847
DOI: 10.1590/2317-1782/20212020325 -
Nederlands Tijdschrift Voor... Sep 2017Elderly persons, especially those suffering from dementia, are at great risk of suffering from oral health problems such as orofacial pain and loss of natural teeth. A... (Review)
Review
Elderly persons, especially those suffering from dementia, are at great risk of suffering from oral health problems such as orofacial pain and loss of natural teeth. A possible explanation could be that the cognitive and motor impairments resulting from dementia cause a decrease in self-care and as such, a worsening of oral health. An alternative explanation is that cognition and oral health influence each other. Animal studies show that a decrease in masticatory activity, for example due to a soft diet or loss of teeth, causes memory loss and neuronal degeneration. The relationship between mastication and cognition has also been researched in human studies, but a cause-effect relationship is not yet evident. It is likely that multiple factors play a role in this relationship, such as self-care, nutrition, stress and pain.
Topics: Aging; Cognition; Dementia; Humans; Mastication; Self Care
PubMed: 28920970
DOI: 10.5177/ntvt.2017.09.16233