-
Zhejiang Da Xue Xue Bao. Yi Xue Ban =... Jun 2023Chewing-side preference is one of the risk factors for temporomandibular disorders (TMD), and people with chewing-side preference is more prone to have short and... (Review)
Review
Chewing-side preference is one of the risk factors for temporomandibular disorders (TMD), and people with chewing-side preference is more prone to have short and displaced condyles, increased articular eminence inclination and glenoid fossa depth. The proportion of TMD patients with chewing-side preference is often higher than that of the normal subjects. Clinical studies have shown a strong correlation between chewing-side preference and TMD symptoms and signs; and animal studies have shown that chewing-side preference can affect the growth, development, damage and repair of the mandible. After long-term unilateral mastication, changes in the stress within the joint cause the imbalance of temporomandibular joint (TMJ) structural reconstruction, the transformation and even destruction of the fiber structure of masticatory muscle, resulting in uncoordinated movement of bilateral muscles. The joint neurogenic diseases caused by the increase of neuropeptide substance P and calcitonin-gene-related-peptide (CGRP) released locally by TMJ may be the mechanism of TMD. This article reviews the research progress of the influence of chewing-side preference on the structure of TMJ, the relationship between chewing-side preference and TMD, and the related mechanisms.
Topics: Humans; Mastication; Temporomandibular Joint; Temporomandibular Joint Disorders; Mandible
PubMed: 37476950
DOI: 10.3724/zdxbyxb-2023-0066 -
Journal of Dentistry Feb 2023To give an overview of the evidence on the associations between oral condition factors and masticatory performance of adults, and to evaluate the direction and level of... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
To give an overview of the evidence on the associations between oral condition factors and masticatory performance of adults, and to evaluate the direction and level of the associations.
DATA/SOURCES
Medline (PubMed), Embase (Ovid) and CINAHL Plus (EBSCOhost) were searched up to May 2022 for cross-sectional studies on oral conditions and masticatory performance in adults. Methodological quality of the included studies was independently evaluated based on the Joanna Briggs Institute critical appraisal checklist for analytical cross-sectional studies. Data on the associations between oral condition factors and masticatory performance were extracted. Meta-analysis was conducted on correlation coefficients.
STUDY SELECTION
Of the 8,035 records identified, 97 articles (88 studies) were included in the qualitative synthesis, and 18 studies were included in the meta-analyses. Among the oral condition factors that had associations with masticatory performance, the number of natural/remaining teeth or functional tooth pairs was reported by the largest number of studies, followed by perioral muscle status, dental prosthetic status, oral moisture status and periodontal status. Results of the meta-analyses showed that the positive association with the number of natural/remaining teeth was the strongest (pooled correlation coefficient: 0.51, 95%CI: 0.48 to 0.54), followed by the number of functional tooth pairs, maximum tongue force/pressure, while the association with the oral moisture status was the weakest.
CONCLUSIONS
Number of natural/remaining teeth and functional tooth pairs, perioral muscle status, oral moisture status, dental prosthetic status and periodontal status are the main oral condition factors influencing masticatory performance. Based on the limited evidence available, among these factors, the number of natural/remaining teeth has the strongest positive association, with a very low quality of evidence.
CLINICAL SIGNIFICANCE
This study provides valuable information on the oral condition factors associated with masticatory performance, which would be important for policymakers and clinical practitioners when deciding on the strategies for improving the masticatory performance of adults. This review highlights the need for standardization of measures and classifications of masticatory performance and oral conditions.
REGISTRATION
PROSPERO (registration number: CRD42021256824).
Topics: Humans; Adult; Bite Force; Mastication; Cross-Sectional Studies; Mouth, Edentulous
PubMed: 36563840
DOI: 10.1016/j.jdent.2022.104395 -
PloS One 2023Monitoring the feeding and ruminating behaviour of ruminants can be used to assess their health and welfare. The MSR-jaw movement recording system (JAM-R) can...
Monitoring the feeding and ruminating behaviour of ruminants can be used to assess their health and welfare. The MSR-jaw movement recording system (JAM-R) can automatically record the jaw movements of ruminants. The associated software Viewer2 was developed to classify these recordings in adult cattle and calculate the duration and number of mastications of feeding and ruminating. The purpose of this study was to evaluate the performance of Viewer2 in classifying the behaviour of sheep and goats and assessing their feeding and ruminating. The feeding and ruminating behaviour of ten sheep and ten goats on pasture (observed live) and of five sheep and five goats in the barn (observed by video) were compared with Viewer2 behaviour classifications. To assess the technical and welfare issues of the JAM-R, its application was tested in a feeding experiment with 24 h monitoring of the feeding behaviours of 24 sheep and 24 goats. Viewer2 worked equally well on both species. The mean (95% confidence interval) performance of Viewer2 was at a good level for feeding (accuracy: 0.8-1.0; sensitivity: 0.9-1.0; specificity: 0.6-0.9; precision: 0.7-0.9) and ruminating (accuracy: 0.8-0.9; sensitivity: 0.6-0.8; specificity: 0.8-1.0; precision: 0.9-1.0) compared with human observations, with minor differences between the conditions on pasture and in the barn. The performance improved when recording frequency was increased from 10 Hz to 20 Hz. Applying the JAM-R in a feeding experiment, 71% of the recordings executed were defined as technically error-free and produced plausible values for feeding behaviours. In conclusion, according to the values of accuracy, sensitivity, specificity and precision, the presented JAM-R system with Viewer2 is a reliable and applicable technology for automatic recording of feeding and ruminating behaviour of sheep and goats on pasture and in the barn.
Topics: Humans; Sheep; Animals; Cattle; Goats; Feeding Behavior; Eating; Ruminants; Mastication
PubMed: 37200299
DOI: 10.1371/journal.pone.0285933 -
Journal of Oral Rehabilitation Dec 2022Speaking depends on refined control of jaw opening and closing movements. The medial pterygoid muscle (MPT), involved in jaw closing, and the lateral pterygoid muscle...
BACKGROUND
Speaking depends on refined control of jaw opening and closing movements. The medial pterygoid muscle (MPT), involved in jaw closing, and the lateral pterygoid muscle (LPT), involved in jaw opening, are two key mandibular muscles in mastication and are likely to be recruited for controlled movements in speech.
OBJECTIVES
Three hypotheses were investigated, that during speech the MPT and LPT: (1) were both active, (2) but exhibited different patterns of activity, (3) which fluctuated with the vowels and consonants in speech.
METHODS
Intramuscular EMG recordings were made from the right inferior head of the LPT and/or the right MPT in five participants during production of 40 target nonsense words (NWs) consisting of three syllables in the form /V C V C ə/ (V = vowel; C = consonant; ə = unstressed, reduced vowel), spoken by each participant 10 times per NW; analysis focussed on the target syllable, C V .
RESULTS
Both MPT and LPT exhibited robust increases in EMG activity during utterance of most NWs, relative to rest. Peak LPT activation was time-locked to the final part of the target consonant (C ) interval when the jaw begins opening for the target vowel (V ), whereas peak MPT activation occurred around the temporal midpoint of V , when the jaw begins closing for C . EMG amplitude peaks differed in magnitude between "high" vowels, i.e., for which the tongue/jaw are high (e.g., in SEEK), and "low" vowels, i.e., for which the tongue/jaw are low (e.g., in SOCK).
CONCLUSIONS
These novel findings suggest a key role for the LPT and MPT in the fine control of speech production. They imply that speech may impose major synergistic demands on the activities of the MPT and the LPT, and thereby provide insights into the possible interactions between speech activities and orofacial activities (e.g. mastication) and conditions (e.g. Temporomandibular Disorders) that involve the masticatory muscles.
Topics: Humans; Pterygoid Muscles; Speech; Electromyography; Masticatory Muscles; Mastication; Movement
PubMed: 36165884
DOI: 10.1111/joor.13377 -
The Journal of Prosthetic Dentistry Feb 2022Denture adhesives are products used by wearers of removable dental prosthesis; however, systematic reviews on their influence on masticatory performance are lacking. (Review)
Review
STATEMENT OF PROBLEM
Denture adhesives are products used by wearers of removable dental prosthesis; however, systematic reviews on their influence on masticatory performance are lacking.
PURPOSE
The purpose of this systematic review was to evaluate the efficiency of denture adhesives in improving the masticatory performance of users of complete dentures (CD).
MATERIAL AND METHODS
This systematic review was organized from the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist, and the methods were registered on the international prospective register of systematic reviews (PROSPERO-CRD42020187385). The focus question was as follows: "Does the use of denture adhesives improve the masticatory performance of patients with removable dental prostheses?" The databases PubMed/MEDLINE, Scopus, Web of Science, and Cochrane Library were used to extract information.
RESULTS
The search yielded 1338 articles, of which 6 met the inclusion criteria and were selected. All included studies were crossover randomized controlled trials including bimaxillary edentulous individuals. Masticatory performance was evaluated by using a comminution and sieve method.
CONCLUSIONS
Denture adhesives significantly increased the masticatory performance of CD users.
Topics: Cross-Over Studies; Denture, Complete; Humans; Mastication; Mouth, Edentulous
PubMed: 33279156
DOI: 10.1016/j.prosdent.2020.10.011 -
Substance Use & Misuse 2020: Few traditions in South Asia have the antiquity and universal acceptance of betel quid and areca nut chewing. Its popularity dates back to ancient times in the...
: Few traditions in South Asia have the antiquity and universal acceptance of betel quid and areca nut chewing. Its popularity dates back to ancient times in the South-Asian community with a foundation based on four factors, i.e. social acceptability, religious beliefs, perceived health benefits and addiction. We aim to provide an overview of its use in the South Asian region. : We performed an electronic search on Medline, Embase and Google Scholar to identify the origins of the various betel quid and areca nut practices pertaining to the South Asian region along with their social and cultural influences. We also studied the prevalence across the region and the health effects, especially carcinogenic, along with the impact of diverse immigration today. : Other than the debate of where it originates, there is a diverse plethora of terms and methods of use of areca nut and betel quid in the region. Although established as a known carcinogen, the incidence is high, especially in the Indian subcontinent, with very few studies focusing on its use alone (without tobacco). The effect of globalization and increased movement of Asians across borders is resulting in changes in the patterns of diseases as well due to wider dissemination of areca nut and betel quid use. : There is a huge loss of lives due to the addiction that areca nut causes. Governments need to tightly regulate the laws and set up tailored programs to tackle this specific issue in this region.
Topics: Areca; Asia; Asian People; Humans; Mastication; Mouth Neoplasms
PubMed: 32569532
DOI: 10.1080/10826084.2020.1753772 -
Journal of Oral Rehabilitation Dec 2022It has not yet been clarified how the type of the chewing task affects related muscle activity and how the suprahyoid muscles contribute to masticatory function in...
BACKGROUND
It has not yet been clarified how the type of the chewing task affects related muscle activity and how the suprahyoid muscles contribute to masticatory function in humans.
OBJECTIVES
This study aimed to investigate the difference in the suprahyoid muscle activity between the freely and unilaterally chewing tasks and between the working and non-working sides during chewing.
MATERIALS AND METHODS
Twenty healthy volunteers were instructed to chew peanuts and two different types of rice crackers in two ways: freely and unilaterally while surface electromyograms of the masseter and suprahyoid muscles were recorded. The chewing duration, number of chewing cycles and chewing rate were compared between the tasks. Furthermore, the masseter and suprahyoid muscle activities per chewing cycle were compared between the sides.
RESULTS
The chewing duration was significantly longer, and the chewing rate was significantly higher during unilaterally chewing than freely chewing. The chewing duration differed significantly among the different foods; the harder the food, the longer the duration. Chewing rate and suprahyoid activity were significantly higher during soft rice cracker chewing. Masseter activity was higher on the chewing side than on the non-chewing side while there was no difference in suprahyoid activity between the sides.
CONCLUSION
The current results demonstrate a difference in the masticatory efficacy between the chewing tasks and a functional role of the suprahyoid muscles during chewing, which does not differ between the chewing and non-chewing sides.
Topics: Humans; Mastication; Masseter Muscle; Neck Muscles; Electromyography; Food; Masticatory Muscles
PubMed: 36151942
DOI: 10.1111/joor.13373 -
In Vitro Mastication Simulation and Wear Test of Virgilite and Advanced Lithium Disilicate Ceramics.The International Journal of... 2022To compare wear behavior, durability during in vitro mastication simulation, and fracture force of an established and a novel lithium disilicate CAD/CAM material, as...
PURPOSE
To compare wear behavior, durability during in vitro mastication simulation, and fracture force of an established and a novel lithium disilicate CAD/CAM material, as well as to examine the impact of cementation and reduced ceramic thickness on durability and fracture force.
MATERIALS AND METHODS
Specimens (n = 8 per group) were prepared from lithium disilicate (LS; IPS e.max, Ivoclar Vivadent) and advanced lithium disilicate (ALD; Cerec Tessera, Dentsply Sirona). Specimens were polished, and two-body wear test and thermocycling were performed (50 N, 120,000 cycles, 1.6 Hz, HO dist., 5°C/55°C, 600 cycles). Maximum vertical loss, surface roughness, surface roughness depth, and antagonist wear were determined. Single crowns (n = 8 per group; thickness 1.5 mm/1.0 mm) were manufactured from LS and ALD and mounted on human molar teeth with adhesive resin (AB; CalibraCeram, Dentsply Sirona), glass-ionomer cement (GIC; Ketac Cem, 3M ESPE), and hybrid glass-ionomer cement (HGIC; Calibra Bio, Dentsply Sirona). Thermocycling and mechanical loading (2 × 3000 × 5°C/55°C, 2 minutes, H0 dist., 1.2 × 10 50 N) were performed. Fracture force was determined by a universal testing machine (1446, ZwickRoell), and one-way analysis and Bonferroni post hoc test (α = .05) were used for statistical analyses.
RESULTS
Mean (ALD: 210 ± 42.4 μm; LS: 264.3 ± 56.1 μm) and maximum (ALD: 391.1 ± 86.3 μm; LS: 518.3 ± 113.2 μm) wear between groups were significantly different (P ≤ .047). Fracture force varied between 1,911.4 ± 468.4 N (ALD/AB 1 mm) and 2,995.3 ± 880.6 N (LS/GIC), without significant differences (P ≥ .152).
CONCLUSION
ALD showed better wear behavior than LS, but provided similar fracture force. Cementation and reduction of ceramic thickness had only minor effects on fracture force.
Topics: Humans; Mastication; Dental Porcelain; Ceramics; Glass Ionomer Cements; Materials Testing; Computer-Aided Design; Surface Properties
PubMed: 35234750
DOI: 10.11607/ijp.7820 -
Revue Neurologique Oct 2019The first study of Constantin von Economo on the mammalian brain was published in 1902. Experiments were carried out in rabbits at the Physiological Institute headed by... (Review)
Review
The first study of Constantin von Economo on the mammalian brain was published in 1902. Experiments were carried out in rabbits at the Physiological Institute headed by Siegmund von Exner-Ewarten in Vienna to investigate the central pathways of chewing and swallowing. After placing cortical lesions, Economo applied cortical and subcortical electrical stimulation to obtain masticatory movements, and tracked degenerated fibers by means of the Marchi method. He traced fibers through the internal capsule, ventral nucleus of the thalamus, subthalamic nucleus, substantia nigra and its connections with the motor nucleus of the trigeminal nerve, and nucleus solitarius. He suggested that the substantia nigra is responsible for coordinating alimentation movements, with the involvement of cranial nerves V, VII, IX and X as well. We discuss these findings in a historical and a modern perspective, including the concept of a central pattern generator in the pontine reticular formation and its interaction with the nucleus solitarius. Today we understand that mastication is a voluntary action controlled by motor cortical areas, by motoneurons of the trigeminal, and by a neural pattern generator in the pons. On the other hand, deglutition comprises 'reflex swallowing' triggered by sensory fibers of cranial nerves V, IX and X, and 'voluntary swallowing' which may be controlled by both cortical fields and subcortical areas, such as the internal capsule, the hypothalamus and the mesencephalic reticular formation.
Topics: Animals; Austria; Brain; Brain Mapping; Chick Embryo; Deglutition; Electrophysiology; History, 19th Century; Humans; Mastication; Neural Pathways; Neurology; Physicians; Publishing
PubMed: 31182311
DOI: 10.1016/j.neurol.2018.10.009 -
Journal of Oral Science 2023To clarify the presence or absence of differences in path pattern and movement during mastication between the habitual and non-habitual chewing sides.
PURPOSE
To clarify the presence or absence of differences in path pattern and movement during mastication between the habitual and non-habitual chewing sides.
METHODS
Participants were 225 healthy adults with natural dentition. Mandibular movement while chewing gummy jelly on each side was recorded, and masticatory path pattern was classified into five types (one normal and four abnormal). The frequency of each pattern was measured and compared between chewing sides. The amount, rhythm, velocity, and stability of movement and masticatory performance were measured and compared between chewing sides.
RESULTS
A normal pattern was observed on the habitual chewing side in 84.4% of participants. There was a significant difference between chewing sides in masticatory path pattern (χ = 35.971, P < 0.001). Values of parameters regarding the amount and velocity of movement and masticatory performance were significantly higher on the habitual chewing side. Values of parameters regarding rhythm and stability of movement were significantly lower on the habitual chewing side.
CONCLUSION
The present findings of functional differences between chewing sides in terms of path pattern and movement during mastication suggest that these factors should be analyzed on the habitual chewing side.
Topics: Adult; Humans; Mastication; Mandible; Food; Mouth, Edentulous; Movement
PubMed: 37394545
DOI: 10.2334/josnusd.23-0101