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Clinical and Experimental Dental... Feb 2023Chewing increases frontal lobe activity, resulting in improved memory, learning ability, and response reaction time. This study aimed to assess the effects of elastic...
OBJECTIVES
Chewing increases frontal lobe activity, resulting in improved memory, learning ability, and response reaction time. This study aimed to assess the effects of elastic oral appliance chewing on the activities and functions of the frontal lobe.
METHODS
The study participants were 15 healthy men with full dentulous (mean age, 27.4 ± 4.1 years). A prospective crossover design was used to assess frontal lobe activities and functions. Changes in frontal lobe activities were measured with near-infrared spectroscopy (NIRS). At baseline, the participants were assessed in the resting state. Changes in channels #7, representing right frontal lobe activities by NIRS, and #10, representing left frontal lobe activities, during the first and second chewing periods in a total of two periods were evaluated. Frontal lobe functions were measured using the Trail Making Test Part A (TMT-A) in the resting state and after elastic oral appliance or gum chewing. These values were compared with each period.
RESULTS
Elastic oral appliance chewing caused significant differences between the baseline and first chewing periods for channel #7 (p = .032) and significant differences between the baseline and second chewing periods for channels #7 and #10 (p < .001 and p < .001, respectively) using NIRS. Moreover, significant differences were found in the TMT-A results between the resting state and elastic oral appliance chewing (p = .04).
CONCLUSIONS
Elastic oral appliance chewing improves frontal lobe activities to a level similar to that obtained with gum chewing.
Topics: Adult; Humans; Male; Young Adult; Chewing Gum; Frontal Lobe; Learning; Mastication; Prospective Studies; Cross-Over Studies
PubMed: 36625848
DOI: 10.1002/cre2.710 -
Journal of Oral Rehabilitation Oct 2023Temporomandibular disorders (TMD) are characterized by pain and impaired masticatory functions. The Integrated Pain Adaptation Model (IPAM) predicts that alterations in... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Temporomandibular disorders (TMD) are characterized by pain and impaired masticatory functions. The Integrated Pain Adaptation Model (IPAM) predicts that alterations in motor activity may be associated with increased pain in some individuals. The IPAM highlights the diversity of patients' responses to orofacial pain and suggests that such diversity is related to the sensorimotor network of the brain. It remains unclear whether the pattern of brain activation reflects the diversity of patients' responses underlying the association between mastication and orofacial pain.
OBJECTIVE
This meta-analysis aims to compare the spatial pattern of brain activation, as the primary outcome of neuroimaging studies, between studies of mastication (i.e. Study 1: mastication of healthy adults) and studies of orofacial pain (i.e. Study 2: muscle pain in healthy adults and Study 3: noxious stimulation of the masticatory system in TMD patients).
METHODS
Neuroimaging meta-analyses were conducted for two groups of studies: (a) mastication of healthy adults (Study 1, 10 studies) and (b) orofacial pain (7 studies), including muscle pain in healthy adults (Study 2) and noxious stimulation of the masticatory system in TMD patients (Study 3). Consistent loci of brain activation were synthesized using Activation Likelihood Estimation (ALE) with an initial cluster-forming threshold (p < .05) and a threshold of cluster size (p < .05, familywise error-corrected).
RESULTS
The orofacial pain studies have shown consistent activation in pain-related regions, including the anterior cingulate cortex and the anterior insula (AIns). A conjunctional analysis of mastication and orofacial pain studies showed joint activation at the left AIns, the left primary motor cortex and the right primary somatosensory cortex.
CONCLUSION
The meta-analytical evidence suggests that the AIns, as a key region in pain, interoception and salience processing, contributes to the pain-mastication association. These findings reveal an additional neural mechanism of the diversity of patients' responses underlying the association between mastication and orofacial pain.
Topics: Adult; Humans; Mastication; Myalgia; Brain; Facial Pain; Neuroimaging
PubMed: 37252887
DOI: 10.1111/joor.13526 -
Journal of Texture Studies Dec 2023Swallowing disorders, or dysphagia, affect a large part of the population due to factors such as degenerative diseases, medication side effects or simply age-related...
Swallowing disorders, or dysphagia, affect a large part of the population due to factors such as degenerative diseases, medication side effects or simply age-related impairment of physiological oropharyngeal function. The management of dysphagia is mainly handles through texture-modified foods of progressively softer, smoother, moister textures, depending on the severity of the disorder. Rheological and physiological-related properties of boluses were determined for a group of five older persons (average age, 74) for a set of texture-modified foods: bread, cheese and tomato and the combination into a sandwich. The softest class was gel food, after which came a smooth timbale; both were compared to boluses of regular food. The subjects chewed until ready to swallow, at which point the bolus was expectorated and measured regarding saliva content, linear viscoelasticity and shear viscosity. The results were compared to those of a previously studied younger group (average age, 38). The general physiological status of the subjects was determined by hand and tongue strength, diadochokinesis and one-legged standing and showed that all subjects were as healthy and fit as the younger group. Age-related properties such as one-legged standing with closed eyes and salivary flow plus bolus saliva content were lower for the older group, but the average chews-until-swallow was surprisingly also lower. Consequently, bolus modulus and viscosity were higher than for the younger group. Overall, the intended texture modification was reflected in bolus rheological and physiological-related properties. Bolus modulus, viscosity, saliva content and chews-until-swallowed all decreased from regular food to timbale food to gel food.
Topics: Humans; Aged; Aged, 80 and over; Adult; Deglutition Disorders; Deglutition; Cheese; Mastication; Rheology
PubMed: 37463674
DOI: 10.1111/jtxs.12789 -
International Journal of Obesity (2005) Dec 2020Early attempts at the objective measurement of food intake in humans followed many heuristic pioneer studies in laboratory animals, which revealed how homeostatic and... (Review)
Review
Early attempts at the objective measurement of food intake in humans followed many heuristic pioneer studies in laboratory animals, which revealed how homeostatic and hedonic factors interact to shape the daily eating patterns. Early studies in humans examined the characteristics of intake responses at discrete ingestive events. Described for the first time in 1969, the edogram consisted of a parallel recording of chewing and swallowing responses during standardized lunches, allowing parameters of the "microstructure of meals" to be quantified under varying conditions of deprivation or sensory stimulation, in parallel with overall meal size, meal duration, and eating rate. Edographic studies showed consistent changes in the microstructure of meals in response to palatability level (increased eating rate, decreased chewing time and number of chews per food unit, shorter intrameal pauses, and increased prandial drinking under improved palatability). Longer premeal deprivation affected the eating responses at the beginning of meals (decreased chewing time and number of chews per food unit) but not at the end. Eating rate decelerated during the course of meals in normal-weight participants but not in participants with obesity. These observations largely agreed with contemporary works using other objective measurement methods. They were confirmed and expanded in later studies, notably in the investigation of satiation mechanisms affecting weight control. Importantly, research has demonstrated that the parameters of the microstructure of meals not only reflect the influence of stimulatory/inhibitory factors but can, per se, exert a causal role in satiation and satiety. The early edographic recording instruments were improved over the years and taken out of laboratory settings in order to address the measurement of spontaneous intake responses in free-living individuals. Much remains to be done to make these instruments entirely reliable under the immense variety of situations where food consumption occurs.
Topics: Appetite; Deglutition; Eating; Energy Intake; Humans; Mastication; Meals; Satiation
PubMed: 32843712
DOI: 10.1038/s41366-020-00653-w -
Dysphagia Feb 2024Tongue function is vital for chewing and swallowing and lingual dysfunction is often associated with dysphagia. Better treatment of dysphagia depends on a better... (Review)
Review
Tongue function is vital for chewing and swallowing and lingual dysfunction is often associated with dysphagia. Better treatment of dysphagia depends on a better understanding of hyolingual morphology, biomechanics, and neural control in humans and animal models. Recent research has revealed significant variation among animal models in morphology of the hyoid chain and suprahyoid muscles which may be associated with variation in swallowing mechanisms. The recent deployment of XROMM (X-ray Reconstruction of Moving Morphology) to quantify 3D hyolingual kinematics has revealed new details on flexion and roll of the tongue during chewing in animal models, movements similar to those used by humans. XROMM-based studies of swallowing in macaques have falsified traditional hypotheses of mechanisms of tongue base retraction during swallowing, and literature review suggests that other animal models may employ a diversity of mechanisms of tongue base retraction. There is variation among animal models in distribution of hyolingual proprioceptors but how that might be related to lingual mechanics is unknown. In macaque monkeys, tongue kinematics-shape and movement-are strongly encoded in neural activity in orofacial primary motor cortex, giving optimism for development of brain-machine interfaces for assisting recovery of lingual function after stroke. However, more research on hyolingual biomechanics and control is needed for technologies interfacing the nervous system with the hyolingual apparatus to become a reality.
Topics: Animals; Humans; Deglutition; Deglutition Disorders; Mastication; Tongue; Hyoid Bone; Biomechanical Phenomena
PubMed: 37326668
DOI: 10.1007/s00455-023-10596-9 -
PloS One 2020The maintenance of postural balance can be influenced by the lifestyle of a population. This study aimed to determine the electromyographic activity of the masseter and...
The maintenance of postural balance can be influenced by the lifestyle of a population. This study aimed to determine the electromyographic activity of the masseter and temporalis muscles during mandibular tasks and habitual and non-habitual chewing in indigenous individuals to reveal the differences among white Brazilian individuals. Sixty Brazilians (18 and 28 years) were divided into two groups: 30 Xingu indigenous individuals and 30 white Brazilian individuals, with 20 men and 10 women in each group. The individuals were assessed using the normalized electromyographic activity of mandibular tasks (rest, protrusion, right and left laterality) and electromyographic activity of masticatory cycles in habitual (peanuts and raisins) and non-habitual (Parafilm M) chewing. Data were analyzed using Student's t-test (p < .05). Comparisons between the groups demonstrated significant differences. Indigenous individuals group presented a decrease in the normalized electromyographic activity of the masticatory muscles during mandibular rest [right masseter (p = .002) and left masseter (p = .004) muscles]. There was increase in the normalized electromyographic activity during protrusion [left temporal (p = .03) muscle]. There was increase in the electromyographic activity during chewing: peanuts [right masseter (p = .001), left masseter (p = .001) and right temporal (p = .01) muscles], raisins [right masseter (p = .001), left masseter (p = .002), right temporal (p = .008), left temporal (p = .01) muscles] and Parafilm M [left masseter muscle (p = .05)]. From the findings of this study, we concluded that in the comparison between indigenous and white individuals, positive changes were observed in the electromyographic pattern of the masticatory muscles in the mandibular postural conditions, with greater masticatory efficiency in the indigenous group.
Topics: Adolescent; Adult; Brazil; Electromyography; Female; Humans; Indigenous Peoples; Male; Masseter Muscle; Mastication; Temporal Muscle; Young Adult
PubMed: 33320876
DOI: 10.1371/journal.pone.0243495 -
European Journal of Oral Sciences Feb 2019Fast eating has been shown to increase the risk of overweight in both children and adults. The objectives of the present study were to investigate the correlation... (Observational Study)
Observational Study
Fast eating has been shown to increase the risk of overweight in both children and adults. The objectives of the present study were to investigate the correlation between chewing rate and the number of chews per mouthful and to evaluate if they were associated with the weight of meal intake. Thirty healthy subjects, aged 18-24 yr, ate a test lunch at their habitual speed until they felt satiated. The activities of masseter and suprahyoid muscles were recorded to determine the number of chews and the moment of swallowing. The weight of meal intake was recorded along with body mass index (BMI), chewing rate, number of chews per mouthful, meal duration, ingestion rate, hunger, and food preference levels. The mean weight (±SD) of meal intake, chewing rate, and number of chews per mouthful were 261.4 ± 78.9 g, 94.4 ± 13.5 chews min , 19.2 ± 6.4 chews per mouthful, respectively. Chewing rate was not correlated with the number of chews per mouthful. The multivariable linear regression showed that meal intake was significantly positively associated with chewing rate, meal duration, and BMI, but inversely associated with the number of chews per mouthful (adjusted R = 0.42). It was concluded that the number of chews was not associated with chewing rate but meal intake was explained by both reduced number of chews and increased chewing rate.
Topics: Adolescent; Body Mass Index; Energy Intake; Feeding Behavior; Female; Humans; Linear Models; Male; Mastication; Young Adult
PubMed: 30378710
DOI: 10.1111/eos.12583 -
Journal of Texture Studies Dec 2021The physiological transformations that happen during oral processing are complex and challenging to capture and measure; however, their knowledge can help design new...
The physiological transformations that happen during oral processing are complex and challenging to capture and measure; however, their knowledge can help design new products for people who struggle with mastication and swallowing. Here we relate chewing, saliva incorporation and bolus properties with initial meat texture. Three different textures (T1-tender, T2-intermediate, T3-tough) were created by cooking meat in different temperature time combinations and "ready-to-swallow" meat boluses were collected from 10 healthy individuals. Masticatory variables, saliva incorporation, and bolus mechanical and geometrical characteristics were analyzed. Meat texture showed significant effect on masticatory variables (number of chews and chewing duration) but not on saliva incorporation. Bolus mechanical characteristics (hardness, cohesiveness and adhesiveness) varied significantly (p < .05) with meat texture, where meat with a harder texture resulted in a harder bolus. Number of bolus particles changed significantly (p < .05) with increasing meat hardness, where harder meat produced more bolus particles. Significant (p < .05) intersubject variability was recorded for masticatory parameters and saliva incorporation. Mechanical and geometrical characteristics of "ready-to-swallow" meat bolus did not vary among subjects.
Topics: Cooking; Deglutition; Humans; Mastication; Meat; Saliva
PubMed: 34486121
DOI: 10.1111/jtxs.12629 -
Dysphagia Aug 2022Mastication problems can have a negative impact on the intake of food and quality of life. This cross-sectional study characterizes mastication problems using clinical... (Review)
Review
Mastication problems can have a negative impact on the intake of food and quality of life. This cross-sectional study characterizes mastication problems using clinical and instrumental assessments in patients with spinal muscular atrophy (SMA) types 2 and 3 with self-reported bulbar problems. We included 27 patients (aged 13-67 years), 18 with SMA type 2 and 9 patients with SMA type 3 (of whom three were still ambulant) and applied a questionnaire, clinical mastication tests (TOMASS and 6-min mastication test), and muscle ultrasound of the mastication muscles. Non-ambulant patients demonstrated inefficient mastication as reflected by median z scores for masticatory cycles (z = 1.8), number of swallows (z = 4.3) and time needed to finish the cracker (z = 3.4), and limited endurance of continuous mastication as demonstrated by the median z scores of the 6-min mastication test (z = - 1.5). Patients reported increased fatigue directly after the 6-min mastication test as well as 5 min after completing the test (p < 0.001; p = 0.003). Reduced maximal mouth opening was associated with mastication problems (p < 0.001). Muscle ultrasound of the mastication muscles showed an abnormal muscle structure in 90% of both ambulant and non-ambulant patients. This study aims to understand the nature and underlying mechanisms of mastication problems in patients with SMA types 2 and 3 with reported bulbar problems.
Topics: Cross-Sectional Studies; Fatigue; Humans; Mastication; Muscular Atrophy, Spinal; Quality of Life
PubMed: 34392389
DOI: 10.1007/s00455-021-10351-y -
Journal of Morphology Nov 2023The highly specialised masticatory apparatus of rodents raises interesting questions about how their skull withstands the intensive and sustained forces produced by...
The highly specialised masticatory apparatus of rodents raises interesting questions about how their skull withstands the intensive and sustained forces produced by biting on hard items. In these mammals, major systematics were explored for a long time based on the adductor muscles' architecture and the related bony structures. The infraorbital foramen stands out, where a hypertrophied head of the zygomaticomandibular muscle passes through-in hystricomorphous rodents-as a direct consequence of the lateral and posterior shift of the preorbital bar. Interestingly, this bar moved laterally and backwards-enlarging the foramen-but it never disappeared throughout evolution, even showing morphological convergence among rodents. Previous research proposed this bar as behaving mechanically similar to the postorbital bar in ungulates, i.e., a safety structure against torsion stress while chewing. We analysed its morphology by mathematically modelling it under bending and torsion scenarios (linearly and elliptically shaped, respectively), and as for biting load propagation (catenary curve). Although the preorbital bar primarily seems to be shaped for withstanding torsional stress (as the postorbital bar in ungulates) and as an escaping point for force propagation, these forces are not a consequence of chewing and grinding foods, but preventing the zygomatic arch from failing when the powerful laterally-displaced jaw adductor muscles are pulling the dentary upwards at biting.
Topics: Animals; Rodentia; Skull; Mastication; Muscles; Bite Force
PubMed: 37856281
DOI: 10.1002/jmor.21646