During chewing, food is reduced in size, while saliva moistens the food and binds the masticated food into a bolus that can be easily swallowed. Characteristics of the oral system, like number of teeth, bite force and salivary flow, will influence the masticatory process. Masticatory function of healthy persons has been studied extensively the last decades. These results were used as a comparison for outcomes of various patient groups. In this review, findings from literature on masticatory function for both healthy persons and patient groups are presented. Masticatory function of patients with compromised dentition appeared to be significantly reduced when compared with the function of healthy controls. The influence of oral rehabilitation, e.g. dental restorations, implant treatment and temporomandibular disorder treatment, on masticatory function will be discussed. For instance, implant treatment was shown to have a significant positive effect on both bite force and masticatory performance. Also, patient satisfaction with an implant-retained prosthesis was high in comparison with the situation before implant treatment. The article also reviews the neuromuscular control of chewing. The jaw muscle activity needed to break solid food is largely reflexly induced. Immediate muscle response is necessary to maintain a constant chewing rhythm under varying food resistance conditions. Finally, the influence of food characteristics on the masticatory process is discussed. Dry and hard products require more chewing cycles before swallowing than moist and soft foods. More time is needed to break the food and to add enough saliva to form a cohesive bolus suitable for swallowing.
Available from: Roxane Anthea Francesca Weijenberg
"Mastication is essential for grinding our food into smaller particles . During chewing, saliva is added to the particles to lubricate them and create a food bolus that can be swallowed . Recently, reports have been published in the literature, stating that mastication might also serve other purposes, such as countering negative effects of stress  or aiding in cognitive function  . "
[Show abstract][Hide abstract] ABSTRACT: The acute effects of chewing gum on cognitive performance, stress, and pain have been intensively studied the last decade. The results have been contradicting, and replication studies proved challenging. Here, we review some of the recent findings of this topic, and explore possible explanations for these discrepancies by incorporating knowledge derived from studies into oral habits and bruxism. Both stress and cerebral functional specialization (i.e., the involvement of specific brain structures in distinctive cognitive processes) are hypothesized to play a major role in the underlying physiological mechanisms of the diverse effects of chewing gum on cognition, stress and pain.
BioMed Research International 05/2015; DOI:10.1155/2015/149431 · 2.71 Impact Factor
"However, regardless whether they contract bilateral or unilaterally, masseter muscles mainly contract concentric during the phase of jaw closing and isometric during the phase of dental occlusion (Christensen and Mohammed, 1997). The neuromuscular control of chewing is required to maintain a constant chewing rhythm under varying food resistance conditions in which the jaw muscle activity, especially the masseter muscle, needed to break solid food (Yoshida et al., 2009; van der Bilt, 2011). Figure 1 The schematic description of the systems involved in the chewing process within the context of this study, the ipsilateral muscle is on the right side of the jaw of the subject, while the contralateral muscle is on the left (see online version for colours) "
[Show abstract][Hide abstract] ABSTRACT: The organisms have limited capacity of entropy generation, when they reach to that limit they die. The aging stress on various organs has already been studied. This study presents a complementary approach by attempting to relate the life expectancy to the entropy generation by the masseter muscles, which involve in the chewing of the foods in the mouth. The masseter muscles of the subject who is consuming food along the guide lines of Institute of Medicine (USA) generates almost 1x105 J/K of entropy during his 76 years of expected life time while chewing his food. The masseter muscles of an obese person, who uptakes 10 % more nutrients generates the same entropy about five years earlier. Our simulations also predict that entropy generation rate of 1.27 kJ/K year in the masseter muscles lead to five years of longer life span compared to an obese individual. The results of this study imply that the concept of the lifespan entropy is indeed correct even at the individual muscle level, and may be employed to estimate the life expectancy of a person.
International Journal of Exergy 01/2015; 18(1):46 - 66. · 0.88 Impact Factor
"Clinical analysis of chewing can be assessed in a spontaneous mealtime context to indicate the proficiency of mastication (what the child does) and can be assessed in a clinical setting under optimal conditions (what the child can) (Bilt, 2011). Speech Language Therapists (SLTs) require a structured observational instrument that (a) is child friendly and easy to implement and (b) can be used to guide therapy goal-setting and/or indicate whether further assessment of the oral or oralpharyngeal phase of the swallow is required. "
[Show abstract][Hide abstract] ABSTRACT: The Mastication Observation and Evaluation (MOE) instrument was developed to allow objective assessment of a child's mastication process. It contains 14 items and was developed over three Delphi rounds. The present study concerns the further development of the MOE using the COSMIN (Consensus based Standard for the Selection of Measurement Instruments) and investigated the instrument's internal consistency, inter-observer reliability, construct validity and floor and ceiling effects. Consumption of three bites of bread and biscuit was evaluated using the MOE. Data of 59 healthy children (6-48 mths) and 38 children (bread) and 37 children (biscuit) with cerebral palsy (24-72 mths) were used. Four items were excluded before analysis due to zero variance. Principal Components Analysis showed one factor with 8 items. Internal consistency was >0.70 (Chronbach's alpha) for both food consistencies and for both groups of children. Inter-observer reliability varied from 0.51 to 0.98 (weighted Gwet's agreement coefficient). The total MOE scores for both groups showed normal distribution for the population. There were no floor or ceiling effects. The revised MOE now contains 8 items that (a) have a consistent concept for mastication and can be scored on a 4-point scale with sufficient reliability and (b) are sensitive to stages of chewing development in young children. The removed items are retained as part of a criterion referenced list within the MOE.
Research in developmental disabilities 04/2014; 35(7):1551-1561. DOI:10.1016/j.ridd.2014.03.035 · 4.41 Impact Factor
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