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Dysphagia Oct 2017Studies of mechanisms of feeding behavior are important in a society where aging- and disease-related feeding disorders are increasingly prevalent. It is important to...
Studies of mechanisms of feeding behavior are important in a society where aging- and disease-related feeding disorders are increasingly prevalent. It is important to evaluate the clinical relevance of animal models of the disease and the control. Our present study quantifies macaque hyolingual and jaw kinematics around swallowing cycles to determine the extent to which macaque swallowing resembles that of humans. One female and one male adult Macaca mulatta were trained to feed in a primate chair. Videofluoroscopy was used to record kinematics in a sagittal view during natural feeding on solid food, and the kinematics of the hyoid bone, thyroid cartilage, mandibular jaw, and anterior-, middle-, and posterior-tongue. Jaw gape cycles were defined by consecutive maximum gapes, and the kinematics of the swallow cycles were compared with those of the two consecutive non-swallow cycles preceding and succeeding the swallow cycles. Although there are size differences between macaques and humans, and macaques have shorter durations of jaw gape cycles and hyoid and thyroid upward movements, there are several important similarities between our macaque data and human data reported in the literature: (1) The durations of jaw gape cycles during swallow cycles are longer than those of non-swallow cycles as a result of an increased duration of the jaw-opening phase; (2) Hyoid and thyroid upward movement is linked with a posterior tongue movement and is faster during swallow than non-swallow cycles; (3) Tongue elevation propagates from anterior to posterior during swallow and non-swallow cycles. These findings suggest that macaques can be a useful experimental model for human swallowing studies.
Topics: Animals; Biomechanical Phenomena; Deglutition; Feeding Behavior; Female; Humans; Jaw; Macaca mulatta; Male; Mastication; Tongue
PubMed: 28528492
DOI: 10.1007/s00455-017-9812-4 -
Anatomical Record (Hoboken, N.J. : 2007) Jan 2017The relative position of the zygomatic root to the dentition plays a crucial role in determining the overall strength of the face in response to bite forces. The...
The relative position of the zygomatic root to the dentition plays a crucial role in determining the overall strength of the face in response to bite forces. The powerful superficial head of the masseter arises there and the zygomaticoalveolar crest (ZAC) is discussed as a buttressing feature of the face. For instance, a more forwardly or backwardly positioned zygomatic root or a lower or higher vertical distance to the dentition could be indicative for evolutionary adaptations to particular loading regimes which are associated with diet. We therefore examined the morphology of the maxilla using state-of-the-art 3D Geometric Morphometric methods. The data set was reduced to a minimum of relevant measurements and includes five landmarks (pr, ol, zm, lingual and buccal midpoint of second molar alveoli) and three curves with semilandmarks along the lingual and buccal alveolar rim and the ZAC. Results show a stunning overlap in shape variation. We find no clear pattern of shape that would allow separating different hominid groups with confidence, except two extreme forms-Paranthropines and Neanderthals. We also find no clear trend over time. Australopithecines, Habilines, Erectines, and Middle Pleistocene Homo can be very similar to modern humans. Even great apes are within or not far from the central shape distribution of Homo, but they separate clearly from gracile and robust Australopithecines. We discuss the shape factors underlying our data. The geometry studied allows simple measurements and analyses and is thus potentially interesting for classification purposes of extreme forms. Anat Rec, 300:160-170, 2017. © 2016 Wiley Periodicals, Inc.
Topics: Animals; Biomechanical Phenomena; Fossils; Hominidae; Mastication; Maxilla; Zygoma
PubMed: 28000406
DOI: 10.1002/ar.23490 -
Journal of Anatomy Sep 2020Ontogenetic changes in the human masticatory complex suggest that bite force, a key measure of chewing performance, increases throughout growth and development. Current...
Ontogenetic changes in the human masticatory complex suggest that bite force, a key measure of chewing performance, increases throughout growth and development. Current published bite force values for humans exist for molar and incisal biting, but few studies measure bite forces across all tooth types, or measure bite force potentials in subjects of different ages. In the absence of live data, models of bite force such as the Constrained Lever Model (CLM), are employed to predict bite force at different bite points for adults, but it is unclear whether such a model can accurately predict bite force potentials for juveniles or subadults. This study compares theoretically derived bite forces and live bite force data, and places these within an ontogenetic context in humans. Specifically, we test whether (1) patterns of maximum bite force increase along the tooth row throughout ontogeny, (2) bite force patterns estimated using the CLM match patterns observed from live bite force data, and (3) changes in bite forces along the tooth row and throughout ontogeny are associated with concomitant changes in adductor muscle leverage. Our findings show that maximum bite forces increase throughout ontogeny and change along the tooth row, with the highest forces occurring at the posterior dentition. These findings adhere to the expectations under the CLM and validate the model's utility in predicting bite force values throughout development. Furthermore, adductor muscle leverage values reflect this pattern, with the greatest leverage values occurring at the posterior dentition throughout ontogeny. The CLM informs our study of mammalian chewing mechanics by providing a model of how morphological changes of the masticatory apparatus during ontogeny affect bite force distribution along the tooth row. Furthermore, the decreased bite force magnitudes observed in juveniles and subadults compared with adults suggest that differences in juvenile and subadult diets may partially be due to differences in bite force production potentials.
Topics: Adolescent; Adult; Biomechanical Phenomena; Bite Force; Child; Female; Humans; Jaw; Male; Mastication; Masticatory Muscles; Models, Anatomic; Young Adult
PubMed: 32406523
DOI: 10.1111/joa.13218 -
Physiology & Behavior Feb 2018The evaluation of mastication is important to understand the masticatory behavior and diagnose feeding difficulties. The objective of this preliminary study was to...
The evaluation of mastication is important to understand the masticatory behavior and diagnose feeding difficulties. The objective of this preliminary study was to verify if there is agreement between objective and subjective validated methods of chewing evaluation in a convenience sample which consisted of 32 adolescents (mean 15.5years), complete permanent dentition and free of tooth decay. The Quality of Masticatory Function Questionnaire with the Food-Mastication, Habits, Meat, Fruit and Vegetables domains was used in the subjective evaluation. The objective aspects consisted of maximum bite force (BF) and masticatory performance (MP) by mastication of cubes of test-material and sieving to determine the median particle size (X) and distribution in the sieves ("b"), and by the colorimetric method using colorchangeable chewing gum. Data were submitted to exploratory analysis, normality test and correlation tests (Pearson/Spearman). The correlation between BF and X (r=-0.43; p=0.02) and between BF and MP chewing gum (r=0.53; p=0.002) was significant with large effect size. The MP evaluated by chewing gum correlated with X (r=-0.34; p=0.055), but not with "b" (r=-0.06; p=0.73), while "b" correlated only with X (r=0.52, p=0.002). No significant correlation was observed between the objective measures and the total score of the subjective evaluation; only a negative correlation was observed between "b" and Meat domain (r=-0.40; p=0.023). The objective methods showed moderate correlation with each other and no agreement between the objective and subjective methods was observed in this sample of healthy adolescents, emphasizing the importance of both aspects in the evaluation of masticatory function.
Topics: Adolescent; Bite Force; Chewing Gum; Female; Humans; Male; Mastication; Reproducibility of Results; Statistics as Topic; Surveys and Questionnaires
PubMed: 29217358
DOI: 10.1016/j.physbeh.2017.12.001 -
International Journal of Environmental... Feb 2023This study evaluates the masticatory efficiency in patients with craniofacial disorders (CD) compared to controls (C). A total of 119 participants (7-21 years), divided...
This study evaluates the masticatory efficiency in patients with craniofacial disorders (CD) compared to controls (C). A total of 119 participants (7-21 years), divided into CD group (n = 42, mean age 13.45 ± 5.2 years) and C group (n = 77, mean age 14.3 ± 3.27 years) under an orthodontic treatment were included. Masticatory efficiency was assessed using a standard food model test. The masticated food was examined according to its number of particles (n) and area (mm), wherein a higher number of particles alongside a smaller area was an indication of better masticatory efficiency. Additionally, the influence of cleft formation, chewing side, dentition stage, age and sex were evaluated. Patients with CD chewed the standardized food in fewer particles (n = 61.76 vs. n = 84.58), with a significantly higher amount of area than the controls (A = 192.91 mm vs. A = 146.84 mm; = 0.04). In conclusion, patients with CD showed a significantly decreased mastication efficiency compared to healthy patients. Factors such as stage of cleft formation, chewing side, dentition stage and age showed an influence on masticatory efficiency, whereas no gender effect on the masticatory efficiency of CD patients was found.
Topics: Adolescent; Child; Humans; Efficiency; Food; Mastication; Orthodontics
PubMed: 36901330
DOI: 10.3390/ijerph20054324 -
Journal of Oral Science Jan 2023This study aimed to clarify the usefulness of automatic cleaning in analysis of occlusal force. The maximum occlusal force was calculated in 151 healthy adults before...
This study aimed to clarify the usefulness of automatic cleaning in analysis of occlusal force. The maximum occlusal force was calculated in 151 healthy adults before cleaning (B), after manual cleaning (M), and after automatic cleaning (A) and compared among the three conditions. The absolute value of the error rate of A, based on M, was calculated. The occlusal forces in M and A were similar and significantly smaller than the occlusal force in B. The absolute error rate of A was 2.4%. These results suggest that automatic cleaning has a similar effect to manual cleaning and can be applied clinically.
Topics: Adult; Humans; Bite Force; Mastication
PubMed: 36310043
DOI: 10.2334/josnusd.22-0252 -
Food Research International (Ottawa,... Sep 2021Texture and structure of breads have been related to oral processing (FOP) performance and sensory perceptions, but moisture content might play a significant role. To...
Texture and structure of breads have been related to oral processing (FOP) performance and sensory perceptions, but moisture content might play a significant role. To evaluate the real impact of breads texture and structure, eliminating the possible role of moisture content, different toasted breads were investigated. Four commercial toasted sliced breads (white bread -WHB-, whole wheat bread -WWB-, non-added sugar bread -NSU-, non-added salt bread -NSA-) with similar ingredients but different texture and structure were selected. Texture and structure were instrumentally and sensory evaluated, besides FOP (total chewing time, number of chews until swallowing, chewing frequency, and mouthful) and bolus properties (moisture, saliva to bread ratio, hardness, adhesiveness, and cohesiveness). Toasted breads showed significant differences in hardness, cutting strength, and porosity, but panelists did not discriminate among them. FOP results indicated that harder samples (NSU) required longer mastication and a number of chews, and open crumb structures (WWB, WHB) with higher cell areas required less mastication. Also, bolus characteristics were affected by bread types, and bread with lower crumb hardness (WHB) produced more cohesive bolus. Having toasted breads allowed to eliminate possible influence of moisture content differences on sensory perception, mouthful and bolus water incorporation during mastication.
Topics: Bread; Deglutition; Mastication; Touch; Touch Perception
PubMed: 34399473
DOI: 10.1016/j.foodres.2021.110477 -
Dental and Medical Problems 2023During mastication, molars are subjected to heavy stress. However, a full explanation of the effects of physiological loads on tooth structures is lacking.
BACKGROUND
During mastication, molars are subjected to heavy stress. However, a full explanation of the effects of physiological loads on tooth structures is lacking.
OBJECTIVES
The study aimed to determine stress in molars and identify the mechanism of enamel damage in the grooves of the teeth during computer-simulated mastication.
MATERIAL AND METHODS
The study was carried out using the finite element method (FEM). A three-dimensional (3D) model of the first mandibular molar and of the crown of the opposing maxillary tooth was created. A food bite was introduced between the antagonistic teeth. The mastication cycle of the bolus was computer-simulated. The equivalent stress in the enamel and dentin of the mandibular molar was calculated according to the modified von Mises (mvM) criterion.
RESULTS
During the simulated chewing activity, the highest equivalent mvM stress and tensile stress concentrated on the molar enamel around the central groove and the foramen cecum. The value of the equivalent mvM stress was close to the tensile strength of the enamel. According to the mvM criterion, the enamel in these areas was exposed to destruction, which coincided with the occurrence of class I caries.
CONCLUSIONS
During mastication, significant tensile and mvM stress concentrates on the mandibular molar enamel around the central groove and the foramen cecum. High stress in these areas may cause prism microfractures and facilitate the bacterial penetration of the enamel.
Topics: Humans; Mastication; Crowns; Dental Enamel; Tooth Crown; Molar
PubMed: 36806730
DOI: 10.17219/dmp/154777 -
International Journal of Environmental... May 2022Associations between masticatory function and nutritional status have been suggested. Masticatory function can be divided into two subdomains, the objective capacity of...
INTRODUCTION
Associations between masticatory function and nutritional status have been suggested. Masticatory function can be divided into two subdomains, the objective capacity of an individual to mix solid food and the individual's subjectively assessed ability to masticate solid food.
AIM
The aims of this study were to assess the relationship between these subdomains and nutritional variables in older, care-dependent individuals.
MATERIALS AND METHODS
From a group of 355 individuals with care dependency and functional limitations, individuals aged 60 and older were selected. By home visits, the subjects underwent an oral examination and answered chewing related questions. Nutritional status was assessed using the Mini Nutritional Assessment. A total of 196 individuals met the age requirement of 60 years or older. Of these, 86 subjects were able to answer the questions.
RESULTS
We could not find any concluding significant associations between the subdomains of masticatory function or the nutritional variables.
CONCLUSIONS
The absence of associations could be explained by the lack of standardized and validated methods to assess masticatory function and they possibly reflect varying underlying constructs. Self-reported questionnaires seem less useful among older and care-dependent individuals, while an objective clinical measurement will be needed when evaluating masticatory function.
Topics: Aged; Humans; Mastication; Middle Aged; Nutritional Status; Research; Surveys and Questionnaires
PubMed: 35627335
DOI: 10.3390/ijerph19105801 -
Effects of chewing on appetite, food intake and gut hormones: A systematic review and meta-analysis.Physiology & Behavior Nov 2015To seek insights into the relationship between chewing, appetite, food intake and gut hormones, and to consider potentially useful recommendations to promote benefits of... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
To seek insights into the relationship between chewing, appetite, food intake and gut hormones, and to consider potentially useful recommendations to promote benefits of chewing for weight management.
MATERIALS AND METHODS
Papers were obtained from two electronic databases (Medline and Cochrane), from searches of reference lists, and from raw data collected from the figures in the articles. A total of 15 papers were identified that detailed 17 trials. All 15 papers were included in the systematic review; however, a further five studies were excluded from the meta-analysis because appropriate information on hunger ratings was not available. The meta-analysis was conducted on a total of 10 papers that detailed 13 trials.
RESULTS
Five of 16 experiments found a significant effect of chewing on satiation or satiety using self-report measures (visual analogue scales, VASs). Ten of 16 experiments found that chewing reduced food intake. Three of five studies showed that increasing the number of chews per bite increased relevant gut hormones and two linked this to subjective satiety. The meta-analysis found evidence of both publication bias and between study heterogeneity (IA(2) = 93.4%, tau(2) = 6.52, p < 0.001) which decreased, but remained, when covariates were considered. Analysis of the heterogeneity found a substantial effect of the fasting period where the duration of fasting influenced the decrease in hunger due to chewing. Prolonged mastication significantly reduces self-reported hunger levels (hunger: − 2.31 VAS point, 95% CI [− 4.67, − 1.38], p < 0.001).
CONCLUSIONS
Evidence currently suggests that chewing may decrease self-reported hunger and food intake, possibly through alterations in gut hormone responses related to satiety. Although preliminary, the results identify a need for additional research in the area. Focused, uniform, experimental designs are required to clearly understand the relationships that exist between mastication, appetite, satiety, food intake and, ultimately, body weight.
Topics: Appetite; Eating; Gastrointestinal Hormones; Humans; Hunger; Mastication; Satiation
PubMed: 26188140
DOI: 10.1016/j.physbeh.2015.07.017