Relevance of a standard food model in combination with electronic jaw movement recording on human mastication pattern analysis

The aim of this paper is to describe the possibilities of analyzing human mastication. The development of a standardized food model is presented. Based on the findings of a systematic literature search an elastic food model was created with the aim of standardizing size and elastic properties. Three different eatable jellied products were chosen, created by a changing of the amount of gelatin (260 Blooms) related to the total mass of the standard jellied food. The different hardness were classified in soft, medium and hard, flavored identically, but stained with different colors: soft-green, medium-yellow, hard-red. A cylindrical form was chosen with a height of 1 cm and a diameter of 2 cm. A standard protocol for analyzing chewing patterns in men was created. The condylographic data off several patients are described in details to demonstrate the possible clinical implementation. The newly developed standard food model (SFM) showed the capability to serve in experimental settings to analyze human mastication, although only a few patients have been examined. In addition, strength and size of the newly developed SFM load the masticatory system in an extent;it should be possible to disclose subclinical symptoms of patients within a short time of examination. The diagnostic procedure of temporo-mandibular disorder (TMD) should be endorsed by this new method. The condylographic data created by a standardized protocol should have the ability to enhance the clinical functional analysis of patients previous to restorative dental procedures.

Nontraumatic Myositis Ossificans in a Muscle of Mastication

Myositis ossificans (MO) is an extraskeletal tumor-like lesion with bone formation, and is relatively rare in the head and neck region. We report herein a clinicopathological analysis of MO associated with a muscle of mastication. The patient was a 70-year-old Japanese woman who presented with a tumorous mass in the right parotid area and no history of trauma. The surgically excised tumorous lesion consisted of proliferating fibroblastic cells with no atypia in the central portion, and a formation of trabecular osteoid and/or bony tissue in the peripheral portion as the so-called “zonal phenomenon”. The final histological diagnosis was MO, and the lesion was located in the posterior belly of the digastric muscle on computer tomography. A review of the literature showed that many cases of MO predominantly affected the medial pterygoid and masseter muscle and showed a history of previous trauma. The present case represents a rare case of nontraumatic MO in the uncommon location of the posterior belly of the digastric muscle.

Study on the Effect of Fibers on the Properties of Asphalt Mastics

To study the influence of fiber on the properties of asphalt mortar,the properties of lignin fiber,polyester fiber,and basalt fiber were summarized and analyzed respectively.The high-and low-temperature properties of fiber asphalt mortar were studied and analyzed by using three indexes,rutting factor and tensile fracture energy.The results showed that all three kinds of fibers could improve the performance of asphalt mortar to varying degrees,with lignin fiber demonstrating the best effect,followed by basalt fiber and polyester fiber.The type the fiber can be selected based on the required thermal stability and cost depending on the project type.

Rheological and physicochemical characteristics of asphalt mastics incorporating lime kiln dust and dolomite powder as sustainable fillers

The filler-bitumen interaction mechanism is one of the most essential phases for comprehending the asphalt mixture's performance.However,despite numerous studies,in-depth knowledge of filler-bitumen reciprocity at a microscale level is yet to be ascertained.The goal of this research is to gain a better understanding of the fillerbitumen microscale interaction in terms of the synergy and coaction between the physicochemical and rheological performance of mastics due to filler inclusions.The rheological properties of two sustainable mastics,dolomite powder(DP)and lime kiln dust(LKD),together with a neat PEN 60/70 binder,were analysed based on a temperature sweep at elevated temperature conditions.Meanwhile,frequency sweep and multiple stress creep recovery(MSCR)tests were also conducted at pavement serviceability temperature using the dynamic shear rheometer(DSR).Physicochemical tests using a scanning electron microscope(SEM)and energy dispersive X-rays(EDX)were conducted to analyse the impact of parameters such as particle shape,grain size,texture,and chemical compositions.The DSR test results showcased how the incorporation of fillers in asphalt binder considerably improved the performance of the binder in terms of rutting and fatigue.Likewise,its strain and nonrecoverable compliance parameters were substantially reduced at higher filler and binder concentrations.Physical filler attributes of low rigden voids(R.V),high fineness modulus(FM),and high specific surface area(SSA)led to greater interfacial stiffness and elasticity in LKD mastics compared to DP mastics at different loading frequencies and temperature levels.The SEM/EDX results also indicated that the elemental calcium and carbon composition of each filler component,together with its grain morphology,strongly influenced its rheological performance.

Analysis on cracking of deck pavement on Jiangyin Bridge

Based on four-year field inspection and investigation on deck pavement of mastic asphalt on Jiangyin Bridge, cracking causes of mastic asphalt are studied. Cracks of deck pavement are summarized on crack length and width to get a clear view of their propagations. Traffic surveys including traffic volume, axle load and vehicle speed were also conducted to assess their influences. Samples taken on-site were tested with pulling-out test and fatigue test to benchmark their properties. According to the inspection and tests results, it is concluded that the cracks are induced by rutting and fatigue. Lack of fatigue resistance, not well bonded to the steel deck and insufficient high temperature stability are supposed to be the main reasons as well as high density of low speed, excessively overloaded trucks.

Comparative study of surface electromyography of masticatory muscles in patients with different types of bruxism

BACKGROUND Bruxism is a rhythmic masticatory muscle activity that occurs involuntarily in a non-physiologically functional state.There is a lack of research classifying the functional status of masticatory muscles in patients with different mandibular movement types(centric clenching or eccentric grinding)of bruxism.AIM To assess the differences of the masticatory muscle activity in patients with different types of bruxism.METHODS A total of 21 subjects with centric bruxism(CB)and 21 subjects with eccentric bruxism(ECB)were screened from college students according to a questionnaire and their tooth wear features.Sixteen subjects with no bruxism were also recruited.The surface electromyography(EMG)signals of the temporalis anterior(TA)and superficial masseter muscle(MM)were measured in different mandibular positions and during the chewing task.The EMG amplitude and chewing cycle duration parameters were then analyzed.RESULTS The CB group showed fewer muscle maximal motor units,with the MM being more pronounced,a higher proportion of muscle contractions to be recruited for the same load of chewing activity,and a longer chewing cycle.The ECB group showed more TA maximal motor units and higher MM activity on the nonworking side in unilateral chewing.CONCLUSION CB mainly affects the MM,and patients with CB show reduced masticatory muscle contraction efficiency and chewing cycle efficiency.ECB mainly affects the TA,and patients with ECB show enhanced contraction of non-functional lateral muscle bundles.

Restricted Daily Feeding of Liquid Meal Reduces the Motivation of Rats to Get Food

To corroborate the hypothesis that mastication affects the motivation to get food, we examined the effects of dietary consistency on the development of meal anticipation in locomotor activity of rats subjected to restricted daily feeding (RF), in which food supply was restricted to a fixed time each day. RF of both liquid and solid meals produced anticipatory locomotor activity. However, the strength of the activity in rats subjected to RF of liquid meal was lower than that in rats subjected to RF of solid meal. These results suggest that the feeding-associated circadian oscillation that developed by feeding with liquid meal is less potent than that in the case of feeding with solid meal. Furthermore, mastication for digesting solid meal might be one of the factors that determine the strength of the feeding-associated circadian oscillation.

Effects of Chewing Frequency on Cerebral Blood Flow and Cognitive Function

The purpose of the present study was to examine the effect of the frequency of mastication on cerebral activation and task scores for computational tasks. Eleven healthy subjects participated in the present study (nine women, two men). Subjects carried out the Uchida-Kraepelin Test for 15 min before and after chewing tasteless gum for five minutes. The oxygenation of the left prefrontal cortex was monitored by near-infrared spectroscopy during the computational tasks. Task scores did not differ significantly according to chewing frequency (p > 0.05). Conversely, the oxygenation value measured after mastication at a chewing frequency of 110 times/minute (Hz) was significantly higher than that observed before mastication (p < 0.05). Meanwhile, before and after levels of oxygenation did not differ significantly for chewing frequencies of 30 Hz and 70 Hz (p > 0.05 for both). The results of the present study suggest that tasteless mastication does not enhance calculation performance, while a high mastication frequency demonstrates an influence on oxygenation. However, our study indicates that chewing tasteless gum per se does not increase cognitive performance.

Gum Chewing and Cognition: An Overview

In recent years, there was a debate about the effects of gum chewing on various aspects of cognitive functioning. In this review, the results of previous studies are presented and summarized. There is a clear indication that gum chewing can improve various aspects of cognitive functioning including memory, attention and both executive and intellectual functioning. However, there is also clear evidence that chewing gum during cognitive tasks can adversely affect task performance. Therefore, it can be concluded that the replication of (beneficial or detrimental) effects of gum chewing on cognition has been proven to be very difficult. Consequently, the robustness of reported effects of gum chewing on cognition has to be questioned. Suggestions for future research are given.

The Effect of Partial Removable Denture Use on Oral Health Related Quality of Life and Masticatory Function, after 5 Years Use

The aim of this study was to evaluate whether partial removable denture use indeed leads to improved oral health related quality of life and masticatory function. Materials and Methods: Partially edentulous patients presenting for removable denture treatment at the Prosthodontics Service in the Hospital Affiliated to Kinshasa University (Democratic Republic of Congo) were assessed for enrolment in this study. After applying exclusion criteria, 378 patients were included in the study, and randomly assigned into 2 groups. Oral health related quality of life (OHIP-23) and mastication time (MaT), number of chewing cycles (MaC), mastication frequency (MaF), and the sizes of the peanut fragments (FraS) were compared in both groups. Statistical significance was set at p < 0.05. Results: The average MaC, MaT, MaF, and FraS were 119 (± SD 53.70), 86.75 (±SD 35.35), 1.38 (±SD 0.25), and 3.3 (±SD 3.25) for the denture group and 77.9 (±SD 23.9), 60.2 (±SD 17.91), 1.29 (±SD 0.15), and 1.5 (±SD 0.7) for the non-denture group, respectively. Conclusion: The overall oral health related quality of life was best in the non-denture than denture.

Alterations in the function of circulating mononuclear cells derived from patients with Crohn’s disease treated with mastic

AIM： To assess the effects of mastic administration on cytokine production of circulating mononuclear cells of patients with active Crohn＇s disease （CD）. METHODS： The study was conducted in patients with established mildly to moderately active CD, attending the outpatient clinics of the hospital, and in healthy controls. Recruited to a 4 wk treatment with mastic caps （6 caps/d, 0.37 g/cap） were 10 patients and 8 controls, all of who successfully completed the protocol. Interleukin-6 （IL-6）, tumor necrosis factor-alpha （TNF-α）, monocyte chemotactic protein-1 （MCP-1）, macrophage migration inhibitory factor （MIF） and intracellular antioxidant glutathione （GSH） were evaluated in peripheral blood mononuclear cells （PBMC） before and after treatment. RESULTS： Treating CD patients with mastic resulted in the reduction of TNF-α secretion （2.1 ± 0.9 ng/mL vs 0.5 ± 0.4 ng/mL, P = 0.028）. MIF release was significantly increased （1.2±0.4 ng/mL vs 2.5 ± 0.7 ng/mL, P = 0.026） meaning that random migration and chemotaxis of monocytes/macrophages was inhibited. No significant changes were observed in IL-6, MCP-1 and GSH concentrations. CONCLUSION： This study shows that mastic acts as an immunomodulator on PBIC, acting as a TNF-α inhibitor and a MIF stimulator. Although further double-blind, placebo-controlled studies in a large number of patients is required to clarify the role of this natural product, this finding provides strong evidence that mastic might be an important regulator of immunity in CD.

Chios mastic treatment of patients with active Crohn's disease

AIM: To evaluate the effectiveness of mastic administra-tion on the clinical course and plasma inflammatory me-diators of patients with active Crohn’s disease (CD).METHODS: This pilot study was conducted in patients with established mild to moderately active CD, attend-ing the outpatient clinics of the hospital, and in healthy controls. Ten patients and 8 controls were recruited for a 4-wk treatment with mastic caps (6 caps/d, 0.37 g/cap). All patients successfully completed the protocol. CD Ac-tivity Index (CDAI), Nutritional Risk Index (NRI), C-re-active protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), monocyte chemotactic protein-1 (MCP-1), and total antioxidant potential (TAP) were evaluated in the plasma at baseline and at the end of the treatment period. Results were expressed as mean values ± SE and P < 0.05 was considered to indicate statistical significance.RESULTS: Patients exhibited significant reduction of CDAI (222.9 ± 18.7 vs 136.3 ± 12.3, P = 0.05) as com-pared to pretreament values. Plasma IL-6 was signifi-cantly decreased (21.2 ± 9.3 pg/mL vs 7.2 ± 2.8 pg/ mL, P = 0.027), and so did CRP (40.3 ± 13.1 mg/mL vs 19.7 ± 5.5, P = 0.028). TAP was significantly increased (0.15 ± 0.09 vs 0.57 ± 0.15 mmol/L uric acid, P = 0.036). No patient or control exhibited any kind of side effects. CONCLUSION: The results suggest that mastic signifi-cantly decreased the activity index and the plasma levels of IL-6 and CRP in patients with mildly to moderately ac-tive CD. Further double-blind, placebo-controlled studies in a larger number of patients are required to clarify the role of this natural product in the treatment of patients with CD.

Potential implications of Helicobacter pylori-related neutrophil-activating protein

Helicobacter pylori （H. pylori） virulence factors pro- mote the release of various chemoattractants/inflam- matory mediators, including mainly the neutrophil- attractant chemokine interleukin-8 and neutrophil- activating protein （NAP）, involved in H. pylor/-induced gastric pathologies. Co-administration of Chios mastic gum （CMG）, which inhibits H. pylor/NAP, with an H. pylori eradication regimen might add clinical benefits against H. pylori-related gastric pathologies, but pos- sibly not CMG as main therapy. Although H. pylori NAP and other H. pylori-related cytotoxins [i.e., vaculating cytotoxin （VacA）] appear to play a major role in gener- ating and maintaining the H. pylori-associated gastric inflammatory response and H. pylor/NAP is a promising vaccine candidate against H. pylori infection （H. pylori-1）, concerns regarding its potential drawbacks, particularly neurogenic ones, due to possible cross- mimicry, should be considered. Possible cross-mimicry between H. p, vlor/ NAP and/or bacterial aquaporin （AQP） and neural tissues may be associated with the anti-AQP-4 antibody-related neural damage in multiple sclerosis （MS）/neuromyelitis optica patients. Moreover, the sequence homology found between H. pylori VacA and human Na＋/K＋-ATPase A subunit suggests that antibodies to VacA involve ion channels in abaxonal Schwann cell plasmalemma resulting in demyelination in some patients. A series of factors have been im- plicated in inducing blood-brain barrier （BBB） disrup- tion, including inflammatory mediators （e.g., cytokines and chemokines induced by H. pylor/-I） and oxidative stress. BBB disruption permits access of AQP4-specific antibodies and T lymphocytes to the central nervous system, thereby playing a major role in multiple sclero- sis pathogenesis. Relative studies show a strong asso- ciation between H. pylori-I and MS. H. pylor/-I induces humoral and cellular immune responses that, owing to the sharing of homologous epitopes （molecular mim- icry）, cross-react with components of nerves, thereby contributing and perpetuating neural tissue damage. Finally, H. pylori NAP also plays a possible pathoge- netic role in both gastric and colon oncogenesis.

Evaluation of gum mastic(Pistacia lentiscus) as a microencapsulating and matrix forming material for sustained drug release

In this study, a natural gum mastic was evaluated as a microencapsulating and matrixforming material for sustained drug release. Mastic was characterized for its physicochemical properties. Microparticles were prepared by oil-in-oil solvent evaporation method. Matrix tablets were prepared by wet and melt granulation techniques. Diclofenac sodium(DFS) and diltiazem hydrochloride(DLTZ) were used as model drugs. Mastic produced discrete and spherical microspheres with DLTZ and microcapsules with DFS. Particle size and drug loading of microparticles was in the range of 22–62 μm and 50–87%, respectively. Increase in mastic:drug ratio increased microparticle size, improved drug loading and decreased the drug release rate. Microparticles with gum: drug ratio of 2:1 could sustain DLTZ release up to 12 h and released 57% DFS in 12 h. Mastic produced tablets with acceptable pharmacotechnical properties. A 30% w/w of mastic in tablet could sustain DLTZ release for 5 h from wet granulation,and DFS release for 8 h and 11 h from wet and melt granulation, respectively. Results revealed that a natural gum mastic can be used successfully to formulate matrix tablets and microparticles for sustained drug release.

Chemical Composition of the Essential Oil of Mastic Gum and their Antibacterial Activity Against Drug-Resistant Helicobacter pylori

Mastic gum is derived from the tree named Pistacia lentiscus that is grown only in Island Hios of Greek.Since Mastic was first reported to kill Helicobacter pylori(H.pylori)in 1998,there has been no further study to elucidate which component of mastic specifically shows the antimicrobial activity against H.pylori.In this study,we examined which component of mastic gum was responsible for anti-H.pylori activity.We prepared the essential oil of mastic gum and identified 20 constituents by GC–MS analysis.Ten standard components were assayed for anti-H.pylori activity,and it clarified that a-terpineol and(E)-methyl isoeugenol showed the anti-H.pylori activity against four different H.pylori strains that were established from patients with gastritis,gastric ulcer and gastric cancer.These components could be useful to overcome the drug-resistance H.pylori growth in stomach.

Discrete Element Simulation of Asphalt Mastics Based on Burgers Model

In order to investigate the viscoelastic performance of asphalt mastics, a micro-mechanical model for asphalt mastics was built by applying Burgers model to discrete element simulation and constructing Burgers contact model. Then the numerical simulation of creep tests was conducted, and results from the simulation were compared with the analytical solution for Burgers model. The comparision showed that the two results agreed well with each other, suggesting that discrete element model based on Burgers model could be employed in the numerical simulation for asphalt mastics.

Rheological Behavior of Basalt Fiber Reinforced Asphalt Mastic

The characters of basalt fiber are analyzed and compared with commonly used fibers. The rheological behaviors of the basalt fiber reinforced asphalt mastic are investigated by the dynamic shear rheological tests and the repeated creep tests. The results show that basalt fiber has excellent reinforced performances, such as high asphalt absorption ratio, low water absorption ratio, high tensile strength, high elastic modulus and high temperature stability. The rutting factor of the fiber reinforced asphalt mastic is higher than the plain asphalt mastic and the reinforced effects are more remarkable under high temperature. The rheological performances of the asphalt mastic demonstrate a good linear relationship between different temperature and loading frequency. The creep stiffness modulus of the asphalt mastic at different loading time can be expressed by power function. Improved Burgers model is used to represent the rheological behaviors of the asphalt mastic with basalt fiber and the model parameters are estimated.

Visco-elastoplastic damage constitutive model for compressed asphalt mastic

In order to describe the three-stage creep behavior of compressed asphalt mastic, a visco-elastoplastic damage constitutive model is proposed in this work. The model parameters are treated as quadratic polynomial functions with respect to stress and temperature. A series of uniaxial compressive creep experiments are performed at various stress and temperature conditions in order to determine these parameter functions, and then the proposed model is validated by comparison between the predictions and experiments at the other loading conditions. It is shown that very small permanent deformation at low stress and temperature increases rapidly with elevated stress or temperature and the damage may initiate in the stationary stage but mainly develops in the accelerated stage. Compared with the visco-elastoplastic models without damage, the predictions from the proposed model is in better agreement with the experiments, and can better capture the rate-dependency in creep responses of asphalt mastic especially below its softening point of 47 ℃

Evaluation Indices of Interaction Ability of Asphalt and Aggregate Based on Rheological Characteristics

In order to find a parameter as the evaluation index that can capture the effect of the interaction between asphalt and aggregate, the rheological properties of asphalt mastics using two kinds of asphalts and four kinds of aggregates under different filler-asphalt ratios were measured by a dynamic shear rheometer （DSR）. Moreover, four rheological parameters of K.Ziegel-B, Luis Ibrarra-A, complex shear modulus ΔG＊and complex viscosity Δη＊ for evaluating the interaction ability were studied. Results indicate that all the four parameters can characterize the interaction ability of asphalt and aggregate correctly and feasibly. Through the comparison of sensitivities and physical meanings of the four parameters, K.Ziegel-B with high sensitivity and exact physical meaning is finally selected as the evaluation index for interaction ability of asphalt and aggregate.

Ability of rotary compactor in compacting consistent slabs and effect of rotary compaction on engineering properties of stone mastic asphalt mixtures

A new automatic rotary compactor and its abilities in compacting stone mastic asphalt （SMA） are presented. Following an overview of the rotary compactor and the compaction procedure, it is demonstrated that the rotary compactor is able to produce uniform slabs with the desired thickness of 65 mm all over around. Furthermore, 132 cored samples from the rotary compactor had been compacted uniformly with approximately 4% optimum air void content. In addition, performance tests results indicate that the rotary compactor produces asphalt mixturures with the requirements of resilient modulus, Marshall stability and flow. A weight factor was introduced for each fraction of aggregates in the degradation analysis to compensate the crushing effect of aggregates during mixing and compacting.