Mastication Of Food Research Articles

Manifestation of preferred chewing side for hard food on TMJ disc displacement side

The purpose of this study was to reveal the relationship between chewing-side preference and anterior disc displacement (ADD) of the TMJ. Thirty-two healthy subjects with ages ranging from 26 to 34 years were selected from volunteer students at the Okayama University Dental School. Subjects were asked to chew freely with two kinds of test foods, beef jerky (hard food) and chiffon cake (soft food), thus expecting different amounts of mechanical loading on the TMJ. One, 4, and 7 s after starting the mastication, subjects were asked to open their mouth momentarily to have a digital image of their mouth taken. The bolus placement area was measured by processing the digital images, calculated as the number of pixel of bolus area. Area asymmetry index was used for the determination of preferred chewing side (PCS). Oblique sagittal MRI scanning in the closed mouth position was taken to evaluate the articular disc position. In asymptomatic subjects with ADD, a significant predominance of the PCS on the ipsilateral side of ADD was observed during the mastication of hard food. On the contrary, no correlation was found between unilateral ADD and PCS for the soft food. From the results of this study, it is suggested that ADD is the associating factor of PCS for hard food. Therefore, it would be necessary to break down the concept of PCS into at least two categories, one for hard food and one for soft food, considering the mechanical loading on the TMJ.

Method of Evaluation of Dynamic Changes in Food Motivation in Rabbits during Successful Food-Procuring Behavior

We developed a method for evaluation of dynamic changes in the level of food motivation in rabbits during successful food-procuring behavior. Quantitative and temporal parameters of food consumption over each successive cycle of food-procuring behavior were used. The amount of consumed food was converted into electrical signal using an electronic balance incorporated into a hardware-software complex. Temporal parameters of food-procuring activity were determined by changes in electric signal in real-time mode. This method makes it possible to record simultaneously food-procuring activity and impulse activity of masticator muscles and esophageal muscles, which enables parallel analysis of rhythms of food consumption, mastication, and swallowing.

Identification of multiple compartments present during the mastication of solid food

The particle size distributions (PSDs) of two portion sizes (2g and 4g) of five foods (cake, cereal bar, muesli bar, cooked pasta and peanuts) after human mastication were determined. The PSD of the expectorated bolus and residual ‘debris’ rinsed from the mouth were each determined by wet sieving. There were significant differences in the PSD between food types, between portion sizes in the debris fraction and between the bolus and debris fractions. The latter suggests the existence of a two compartment system where particles are comminuted in at least one compartment within the oral cavity.

The masticatory system under varying functional load. Part 2: effect of reduced masticatory load on the degree and distribution of mineralization in the rabbit mandible

A reduction in mechanical loading of the mandible brought about by mastication of soft food is assumed to decrease the remodelling rate of bone, which, in turn, might increase the degree of bone mineralization. The effect of a reduction in masticatory functional load on the degree and distribution of mineralization of mandibular bone was investigated in male juvenile New Zealand White rabbits. The experimental animals (n=8) had been raised on a diet of soft pellets from 8 to 20 weeks of age, while the controls (n=8) had been fed pellets of normal hardness. The degree of mineralization of bone (DMB) was assessed at the attachment sites of various jaw muscles, the condylar head, and the alveolar process. Differences between groups and among sites were tested for statistical significance using a Student's t-test and one-way analysis of variance, respectively. The DMB did not differ significantly between the experimental and control animals at any of the sites assessed. However, in the rabbits that had been fed soft pellets, both cortical bone at the attachment sites of the temporalis and digastric muscles and cortical bone in the alveolar process had a significantly higher DMB than cortical bone at the attachment site of the masseter muscle, while there were no significant differences among these sites in the control animals. The results suggest that a moderate reduction in masticatory functional load does not significantly affect the remodelling rate and the DMB in areas of the mandible that are loaded during mastication but might induce a more heterogeneous mineral distribution.

Blood Pressure and Cerebral Blood Flow Volume Responses to Mastication of Food

Blood Pressure and Cerebral Blood Flow Volume Responses to Mastication of Food

Automatic, computer‐based speech assessment on edentulous patients with and without complete dentures – preliminary results

Dental rehabilitation of edentulous patients with complete dentures includes not only aesthetics and mastication of food, but also speech quality. It was the aim of this study to introduce and validate a computer-based speech recognition system (ASR) for automatic speech assessment in edentulous patients after dental rehabilitation with complete dentures. To examine the impact of dentures on speech production, the speech outcome of edentulous patients with and without complete dentures was compared. Twenty-eight patients reading a standardized text were recorded twice - with and without their complete dentures in situ. A control group of 40 healthy subjects with natural dentition was recorded under the same conditions. Speech quality was evaluated by means of a polyphone-based ASR according to the percentage of the word accuracy (WA). Speech acceptability assessment by expert listeners and the automatic rating of the WA by the ASR showed a high correlation (corr = 0.71). Word accuracy was significantly reduced in edentulous speakers (55.42 +/- 13.1) compared to the control group's WA (69.79 +/- 10.6). On the other hand, wearing complete dentures significantly increased the WA of the edentulous patients (60.00 +/- 15.6). Speech production quality is significantly reduced after complete loss of teeth. Reconstitution of speech production quality is an important part of dental rehabilitation and can be improved for edentulous patients by means of complete dentures. The ASR has proven to be a useful and easily applicable tool for automatic speech assessment in a standardized way.

Simulation of food mastication based on discrete element method

The information on mastication and food sensory properties is usually collected by recording people's ingesting and chewing actions using electromyography, fluorography, cinephotography, videofluorography, ultrasonography, magnetic resonance imaging and so on. The process of human food mastication and swallowing is investigated by Discrete (or Distinct) Element Method (DEM) in this work. The fundamental concepts and algorithms of DEM are presented in this paper. Two initial models of human chewing and swallowing are constructed and relevant simulations are executed by PFC2D software. The first biting of rectangle food, round food, round food with a hole and the food swallowing are simulated. Changes in food reduction and jaw motion with respect to food mechanical properties and oral cavity state are observed during simulations. The movement and interaction of food particles, contact forces between the particles and teeth are analysed. Results from simulations can help understand masticatory performance and promote food product development.

Discopathy and osteoarthritis of temporomandibular joint in a patient with Paget's disease and osteoporosis — A case report

This case report describes a two-year treatment and follow-up of the temporomandibular joint (TMJ) disorder in a 58-year old retired female patient with previously diagnosed Paget’ s disease of bone (PGB). The patient was examined in 2006 due to clicking and pain in the right TMJ. The pain in the right TMJ was especially strong during speech and mastication of solid food, or on wider opening of the mouth. Pain intensity was rated on a visual-analogue scale (VAS=7). The mentioned symptoms appeared in 2004, when she visited an oral surgeon and was advised to perform oral exercises. Since PGB was diagnosed accidentally in 1992 on the basis of observed radiographic abnormalities during an examination of the urotract (radiographic irregularities in pelvic bones on right side), a multidisciplinary managing of the patient was indicated. The pagetic bones were compensated and she was treated with D vitamin only. Anterior disc displacement and shape loss as well as severe sclerosation with osteophyte formation of condyle in the right TMJ was shown by magnetic resonance imaging, and computed tomography confirmed degenerative disease of right TMJ and excluded any maxillary or mandibular bone abnormalities. Further treatment was performed in cooperation with a physiatrist-rheumatologist during 2007. The patient underwent physical therapy based on Schulte and continued the exercises at home, however, she was also advised to start treatment for osteoporosis. At the beginning of 2008 she obtained the occlusal splint again, however she was hospitalised in the meantime due to acute pains in the lower right lumbar region (lumbosacral syndrome). Recent densitometry showed spinal osteoporosis (Tscores: L1 -2.5, L2 -2.9, L3 -2.4). There is some limitation in the oral function therapy in patients with musculoskeletal and endocrinological diseases. Finally, the decision to begin with oral bisphosphonate therapy remains in the domain of her endocrinologist.

Cooking and the Human Commitment to a High-quality Diet

For our body size, humans exhibit higher energy use yet reduced structures for mastication and digestion of food compared to chimpanzees, our closest living relatives. This suite of features suggests that humans are adapted to a high-quality diet. Although increased consumption of meat during human evolution certainly contributed to dietary quality, meat-eating alone appears to be insufficient to support the evolution of these traits, because modern humans fare poorly on raw diets that include meat. Here, we suggest that cooking confers physical and chemical benefits to food that are consistent with observed human dietary adaptations. We review evidence showing that cooking facilitates mastication, increases digestibility, and otherwise improves the net energy value of plant and animal foods regularly consumed by humans. We also address the likelihood that cooking was adopted more than 250,000 years ago (kya), a period that we believe is sufficient in length for the proposed adaptations to have occurred. Additional experimental work is needed to help discriminate the relative contributions of cooking, meat eating, and other innovations such as nonthermal food processing in supporting the human transition toward dietary quality.

Dental Malocclusion in a Coarse-Haired Wombat (Vombatus Ursinus)

A female coarse-haired wombat held in captivity at the San Diego Zoo from approximately 2 to 16 years-of-age developed a dental malocclusion as a consequence of tooth overgrowth. The incisor premolar and molar teeth in this species are classified as aradicular hypsodont and continue to grow throughout life, presumably to counter the abrasive character of the high fiber high ash, and high silica natural diet. In this case, there was a developmental defect of the maxillary incisor teeth, preventing functional interaction of the maxillary and mandibular incisor teeth. In addition, the captive diet appeared to be insufficiently abrasive, resulting in overgrown and malaligned premolar and molar teeth that were progressively less effective in food mastication and impinged on the tongue and buccal mucosa resulting in soft tissue lesions. The wombat was humanely euthanized, and comparisons of skull appearance and tooth position were made with those features in a wild-caught zoological specimen from the Smithsonian Institution.

일부 지역사회 노인들의 우울수준과 관련요인

Objectives: This study was performed to determine the levels of depression symptoms among the community elderlies and to reveal its related factors, specifically aimed at revealing psycho-social factors such as social support net-work, sense of self-esteem, state anxiety, interpersonal behavior trait and locus of control. Methods: The interviews were performed during the period from April 1st to June 30th, 2007 to the 790 elderlies in urban and rural areas. Results: The mean scores of depression (CES-D) among all subjects were 16.65±10.97(urban: 18.81±10.31, rural: 14.49±11.20) and they were higher in urban than rural. The level of depression symptoms was influenced by the variables of educational level, with or without spouse, bear for living expenses, sense of satisfaction in daily life. As for health related behaviors, they were influenced by the variables of with or without regular exercise. As for health status, they were influenced by the subjective health status, with or without disability of body, visual acuity, hearing ability, ability of food mastication, urinary incontinence, with or without help in activity of daily living (ADL) and instrumental activity of daily living (IADL). As for social support net-work and social activities, they were influenced by number of offspring, frequency of offspring contents, frequency of going out and activity of hobbies. As for psycho-social factors, they were influenced by sense of self-esteem, state anxiety and social support, especially, the level of depression symptoms was higher influenced by the variables of psycho-social factors than other variables. Conclusions: Lower of the level of depression symptoms among the community elderlies would require development and application of programs to keep under management psycho-social factors as well as looking for ways to promoting the present health status.

Object-oriented knowledge framework for modelling human mastication of foods

To model human mastication of foods, an object-oriented knowledge framework is developed that consists of three class objects, one for the physiology related to the mastication, one for the masticatory measurements, and the other for the factors affecting mastication. Each class object is structured in a hierarchy of sub-objects according to the domain or literature knowledge. The knowledge about the relationships among the attributes of objects is represented by IF–THEN rules. These rules can be discovered from the experimental database following the knowledge discovery in database. A case study is presented where a foods chewing database involving EMG mandibular movement measurements is used, two decision trees are discovered with respect to the type of rheological properties and hardness, and the rules derived are expressed in the context of the knowledge framework.

Benefits of Chewing Gum

In Brief Although chewing is an important part of eating, it is becoming apparent that the benefits of chewing may extend far beyond the mastication of food in preparation for swallowing. Consumers around the globe chew gum for many reasons-oral care, fresh breath, and good taste. Oral health benefits from chewing sugar-free gum have been well established through accepted scientific research. More recent research suggests that chewing gum may have a positive impact on cognitive function, specifically concentration and focus and weight management and even in helping individuals to cope with "life's small stresses." The potential benefits of gum chewing

Can We Rescue Salivary Gland Function after Irradiation?

Hyposalivation induced by exposure of the salivary gland to radiation while treating head and neck cancer patients, can result in xerostomia (dry mouth syndrome), which burdens the patient with oral dryness or pain, dental caries, reduced taste and smell, increased risk for oral infections, hampered speech, and problems with food mastication. Stem cell therapy may be an option to reduce radiation-induced damage to the salivary glands permanently. This Directions in Science article reviews a recent study (Lombaert et al, 2008) using tissue stem cells to regenerate the salivary glands from cells that originate from putative stem cells residing in the ductal compartment. Lombaert et al showed restoration of function of irreversibly damaged mouse submandibular glands after intraglandular injection of an in vitro cultured c-Kit+ cell population containing salivary gland stem cells. The findings raise the prospect of clinical autologous salivary gland stem cell transplantation after radiotherapy.

Mastication of model products in complete denture wearers

Objective The aim of this study was to define the characteristics of muscular activity in complete denture wearers and in dentate subjects during mastication of model foods differing in hardness but similar in terms of rheologically properties. Material and methods The foodstuffs used in this study were laboratory-developed gumdrops demonstrating viscoelastic properties. The test foods cover a range of four hardness levels. The group of complete denture wearers included 15 subjects, while the control group included 9 subjects with normal dentition. Electromyograph (EMG) recordings were taken from the masseter and temporal muscles during mastication of the test foods. The results were evaluated by one-way and two-way ANOVA followed by means comparisons using a Student–Newman–Keuls post hoc test ( α = 0.05). Results Preparing the same food bolus for swallowing required a greater number of masticatory cycles and a longer duration of mastication for complete denture wearers than for dentate subjects. In addition, complete denture wearers failed to increase EMG activity per cycle in response to hardness of the food. Conclusion Denture wearers experienced difficulties during mastication, as indicated by a decreased masticatory rate and the observed failure to increase EMG activity per cycle in response to increased food hardness. The increases in number of cycle and masticatory duration appear to be a response to this impaired masticatory function .

A prospective study of immediately loaded single implant-retained mandibular overdentures: Preliminary one-year results

The cost of rehabilitation of the problematic mandibular complete denture with implant-retained overdentures or implant-supported fixed prostheses is beyond the financial scope of many compromised denture patients. Therefore, a more affordable treatment alternative is desirable. The purpose of this preliminary study was to investigate the predictability of simplifying mandibular overdenture treatment using single-stage surgery and immediate prosthetic loading of a single implant. Twenty-eight patients with a mean age of 69.8 years and problematic mandibular dentures were treated. The primary complaints among the patients referred to the clinic for treatment related to poor retention of the mandibular denture, instability, denture sores, and phonetic problems. A single implant (Branemark TiUnite Mk III) was placed into the mandibular midline, achieving primary stability. A ball attachment was placed and the retentive cap incorporated into the existing denture. The patients were recalled at 3 and 12 months. Clinical assessments, radiographs made with custom film holders, and stability measurements by both manual and resonance frequency analysis methods were recorded. All complications, failures, maintenance, and reasons for failure to follow-up were noted. Visual analogue scale questionnaires were used to record patient satisfaction. A 1-way repeated-measures ANOVA was used to determine differences between means in the following categories: general satisfaction, social life, mastication of hard food, comfort, and fit (P=.05). Three implants did not achieve sufficient primary stability to be immediately loaded and were, therefore, treated with a 2-stage delayed loading protocol. The 25 immediately loaded implants were all surviving at the 12-month recall. Patient satisfaction was high, with a significant increase in all comfort and functional parameters (P values ranged from <.001 to .07). These preliminary 1-year results indicate that immediate loading of a single oxidized surface implant used to retain a mucosa-borne overdenture is a safe, reliable, and cost-effective treatment.

Integrating dental microwear and isotopic analyses to understand dietary change in east-central Mississippi

Stable isotope and dental microwear analyses are integrated to observe changes in plant food diet in east-central Mississippi. Dental specimens are compared from seven sites in Mississippi and one in Alabama ranging in time from the Archaic to the Protohistoric periods. Microwear analysis of phase II dental facets is performed and pit percentages, scratch length and width, and pit length and width are recorded. Analysis of variance statistical tests were performed between temporally contiguous sites. The results indicate that the size and frequency of microwear features decrease through time until the Protohistoric period where pit feature size and frequencies increase significantly. These results are then compared to stable isotope analysis to test whether the methods yield congruent results and to assess additional dietary changes, specifically the increased importance of nut foods. Carbon isotope analysis indicates differences in dietary maize use between the Mississippian and Protohistoric samples and dental microwear analysis show a significant increase in pit percentages and pit size, microwear features generally associated with hard food mastication. One important question addressed is whether there was a return in the Protohistoric period to naturally available resources, specifically hard foods such as nuts, a pattern observed at sites in Alabama and Arkansas. The use of secondary burials in the later Protohistoric period is examined as a possible cause for this microwear pattern. The study demonstrates the importance of integrating different methods when assessing dietary change, especially when ethnobotanical information is not available.

Particle size distribution in the food bolus after mastication of natural foods

Abstract The main goal of mastication is to prepare a food bolus suitable for deglutition. The bolus preparation consists in food breakdown and processing during which oral sensations are generated. This study was performed to examine the particle size distribution in the bolus formed by chewing 10 natural foods. Ten young subjects with normal dentition were asked to chew the food and to expectorate the bolus just before swallowing, while masticatory parameters were recorded. The particle size distribution of each bolus was evaluated by wet sieving. The number of cycles, sequence duration and masticatory frequency varied among subjects and foods. The particle size distributions differed among foods but were similar among subjects. The median particle size d50 gave a range from 0.82 to 3.04 mm allowing a food classification based on the state of the bolus. The d50 value reflected the fracturability and may be useful to describe food behaviour in the mouth during bolus preparation.

The Interactive Effects of Exercise and Feeding on Oxygen Uptake, Activity Levels, and Gastric Processing in the Graceful CrabCancer gracilis

Exercise and digestive processes are known to elevate the metabolic rate of organisms independently. In this study, the effects of simultaneous exercise and digestion were examined in the graceful crab Cancer gracilis. This species exhibited resting oxygen uptake levels between 29 and 42 mg O(2) kg(-1) h(-1). In postprandial crabs, oxygen uptake was approximately double that of unfed crabs. During exercise, oxygen uptake increased three- to fourfold, reaching maximal levels of more than 130 mg O(2) kg(-1 ) h(-1). However, there was no difference in oxygen uptake during activity between unfed and postprandial animals. There was also no difference in exercise endurance levels between unfed and postprandial animals; both sets of animals were unable to right themselves after being turned on their backs, reaching exhaustion after 13-15 attempts. To determine whether increased activity affected gastric processes, the passage of a meal through the digestive system was followed using a fluoroscope. Passage of digesta through the gut system was slower in active animals than in resting crabs. Resting crabs cleared the foregut after approximately 18 h, which was significantly faster than the 34.5 h for constantly active animals. Likewise, the midgut region of resting animals was cleared at a faster rate than that of active animals. Because of residual amounts of digesta remaining in the hindgut, no difference in clearance rates of this section of the gut was evident. The slower clearance times of the foregut were due to a significantly slower rate of mastication of food, as evidenced by a lower cardiac stomach contraction rate. Contraction of the pyloric region of the foregut functions to move the digesta along the midgut, and there was a direct correlation between slower contraction rates of this region and the increased time of passage for digesta through the midgut of active animals. Because increased activity levels affected gastric processing, the crabs exhibited a behavioral response. During a 24-h period after feeding, there was a significant reduction in locomotor activity. The findings of this study suggest a prioritization of metabolic responses toward activity at the expense of digestion. This is discussed in relation to the ability of the crabs to balance the demands of competing physiological systems.

Structural behaviour of endodontically treated teeth under thermomechanical loading

Choosing the optimal combination of post construction and restorative materials to minimize thermomechanical stresses in endodontically post-restored teeth is a very challenging task. In fact, while thermal properties of metallic alloys used for endodontic posts are rather similar to those of natural dental tissues, composite restorative materials used for constructing post and postcore usually possess better mechanical properties than metallic alloys. This may make it very difficult to evaluate directly thermomechanical stresses in the restored tooth. Therefore, this paper presents a detailed analysis of the structural behaviour of several post-endodontic restorations submitted to different combinations of thermomechanical load. The aim of the study is to compare the relative merits of different restoration concepts. Three-dimensional finite element method (FE) analysis is carried out for an upper incisor restored with composite as well as metallic post systems. Furthermore, customized and standard post constructions are compared. Two loading cases are considered: (a) exposure to cold irritants in absence of mastication; (b) mastication of cold or hot foods. Effects of thermal field inhomogeneity and occlusal force magnitude are also included in the analysis. Because of the transient nature of thermal loads, relative performance of different restorations is investigated as the thermal perturbation spreads through the restored tooth. Results indicate that composite post systems are globally more efficient than restorations including a metallic alloy post when thermal cycles and mastication act together. However, relative performance of different restoration concepts in the absence of mastication may depend strongly on the time of exposure to thermal irritants.