Hard Food Research Articles

Effectiveness of buccal dental‐microwear texture in African Cercopithecoidea dietary discrimination

AbstractObjectivesThis study compares ISO (ISO/FDIS 25178) roughness parameters, calculated from three‐dimensional (3D) molar buccal microtexture surfaces, among African Cercopithecoidea primates with different diets.Materials and MethodsWe examined 98 lower second molars from seven African Cercopithecoidea species with diverse dietary regimes and habitat exploitation. Buccal dental surfaces were analyzed using a Sensofar Plu Neox laser scanning confocal microscope. Thirty‐eight, areal surface texture parameters were extracted (Mountain 7® software). Uni‐ and multivariate statistics were used to obtain diet‐related patterns of buccal‐microwear textures and feeding ecology to differentiate between species.ResultsBuccal‐dental 3D texture parameters discriminate between Cercopithecoidea diets. Analysis of variance (ANOVA) revealed significant variation in microwear texture between forest‐adapted Mandrillus sphinx, which showed coarse flat features, and grassland forager Theropithecus gelada, whose buccal surfaces were characterized by a high density of thin features. Buccal‐microwear textures of folivorous species (Colobus polykomos) were related to a lower density of thicker surface indentations in comparison to Papio anubis and Cercocebus atys which are adapted to the consumption of tough and hard foods. The limited interspecific variation in the buccal‐microwear textures of savanna dwellers (Chlorocebus pygerythrus and Chlorocebus aethiops) probably reflects similarities in their foraging diets.DiscussionSignificant variations between‐species demonstrate that 3D microwear ISO roughness parameters applied to buccal enamel surfaces can distinguish between the diets of Cercopithecoidea.

Taking a stab at modelling canine tooth biomechanics in mammalian carnivores with beam theory and finite-element analysis.

Canine teeth are vital to carnivore feeding ecology, facilitating behaviours related to prey capture and consumption. Forms vary with specific feeding ecologies; however, the biomechanics that drive these relationships have not been comprehensively investigated. Using a combination of beam theory analysis (BTA) and finite-element analysis (FEA) we assessed how aspects of canine shape impact tooth stress, relating this to feeding ecology. The degree of tooth lateral compression influenced tolerance of multidirectional loads, whereby canines with more circular cross-sections experienced similar maximum stresses under pulling and shaking loads, while more ellipsoid canines experienced higher stresses under shaking loads. Robusticity impacted a tooth's ability to tolerate stress and appears to be related to prey materials. Robust canines experience lower stresses and are found in carnivores regularly encountering hard foods. Slender canines experience higher stresses and are associated with carnivores biting into muscle and flesh. Curvature did not correlate with tooth stress; however, it did impact bending during biting. Our simulations help identify scenarios where canine forms are likely to break and pinpoint areas where this breakage may occur. These patterns demonstrate how canine shape relates to tolerating the stresses experienced when killing and feeding, revealing some of the form–function relationships that underpin mammalian carnivore ecologies.

A new diminutive durophagous Miocene dasyuromorphian (Marsupialia, Malleodectidae) from the Riversleigh World Heritage Area, northern Australia

ABSTRACT Malleodectes? wentworthi, sp. nov. is a highly specialized durophagous marsupial from a Middle Miocene limestone cave deposit in the Riversleigh World Heritage area, northern Australia. It provides the first information regarding the lower dentition of malleodectids, an extinct family of dasyuromorphians. It is also the smallest durophagous member of Metatheria (marsupials and their stem relatives) known to date, with an estimated body mass of ∼70–90 g, an order of magnitude smaller than other known malleodectids (Malleodectes mirabilis and Ma. moenia ∼1 kg). As in other malleodectids, Ma.? wentworthi has a hypertrophied, dome-like premolar specialized for crushing hard foods. Tentative assignment to the genus Malleodectes is based on derived similarities of the premolar and molar dentition to those of larger species of Malleodectes (known only from upper dentitions), and occlusal compatibility. Quantitative morphofunctional analyses of dental indices and mandibular bending strength are congruent with the previously proposed hypothesis that malleodectids may have been uniquely specialized snail-eaters. Maximum parsimony phylogenetic analysis of a 173 morphological character dataset, with a molecular scaffold enforced, placed Ma.? wentworthi within Dasyuromorphia, in a basal polytomy with Dasyuridae and Mutpuracinus archibaldi, to the exclusion of Barinya wangala, Myrmecobiidae and Thylacinidae. Bayesian analysis of a total evidence dataset that combined morphological with nuclear and mitochondrial DNA sequence data places Ma.? wentworthi as a sister taxon to crown-clade Dasyuridae, although support for this relationship is weak.

Microwear textures associated with experimental near-natural diets suggest that seeds and hard insect body parts cause high enamel surface complexity in small mammals

In mammals, complex dental microwear textures (DMT) representing differently sized and shaped enamel lesions overlaying each other have traditionally been associated with the seeds and kernels in frugivorous diets, as well as with sclerotized insect cuticles. Recently, this notion has been challenged by field observations as well as in vitro experimental data. It remains unclear to what extent each food item contributes to the complexity level and is reflected by the surface texture of the respective tooth position along the molar tooth row. To clarify the potential of seeds and other abrasive dietary items to cause complex microwear textures, we conducted a controlled feeding experiment with rats. Six individual rats each received either a vegetable mix, a fruit mix, a seed mix, whole crickets, whole black soldier fly larvae, or whole day-old-chicks. These diets were subjected to material testing to obtain mechanical properties, such as Young’s modulus, yield strength, and food hardness (as indicated by texture profile analysis [TPA] tests). Seeds and crickets caused the highest surface complexity. The fruit mix, seed mix, and crickets caused the deepest wear features. Moreover, several diets resulted in an increasing wear gradient from the first to the second molar, suggesting that increasing bite force along the tooth row affects dental wear in rats on these diets. Mechanical properties of the diets showed different correlations with DMT obtained for the first and second molars. The first molar wear was mostly correlated with maximum TPA hardness, while the second molar wear was strongly correlated with maximum yield stress, mean TPA hardness, and maximum TPA hardness. This indicates a complex relationship between chewing mechanics, food mechanical properties, and observed DMT. Our results show that, in rats, seeds are the main cause of complex microwear textures but that hard insect body parts can also cause high complexity. However, the similarity in parameter values of surface textures resulting from seed and cricket consumption did not allow differentiation between these two diets in our experimental approach.

Endodontic reintervention of a mandibular second premolar with four root canals: a case report

Complex anatomical variations on root canals morphology are one of the most arduous challenges in the endodontic practice. The objective of this case report is to discuss the clinical management of a mandibular left second premolar with four root canals and four distinct apical foramina. This case report has been written according to Preferred Reporting Items for Case reports in Endodontics (PRICE) 2020 guidelines. A 74-year-old patient was referred to retreat a left mandibular second premolar. The patient complained of discomfort when chewing hard food. After obtaining consent from the patient to investigate the symptoms, a thorough clinical and radiographic examination was performed. The main clinical findings observed were a moderate sensitivity to vertical percussion and mild discomfort at palpation. The periapical radiograph showed a fusion-like root with multiple canals and unsatisfactory root canal fillings associated with apical radiolucency. Based on this investigation, a diagnostic of persistent apical periodontitis was made to the tooth, and nonsurgical root canal re-treatment was proposed to the patient. After written informed consent was obtained, the procedure was performed under magnification provided by a dental operating microscope with the aid of ultrasonic tips. During the access opening and fillings removal, four root canal orifices were observed. Therefore, state-of-the-art technology such as the dental operating microscope, ultrasonics, and cone-bean computed tomography image are strong allies to manage anatomical variations.

Use of Flexible Bronchoscopy in Foreign Body Aspiration.

Objective:Foreign body aspiration remains a serious health problem with a potential for severe consequences, and acute and chronic problems in children. It therefore demands immediate intervention. Rigid bronchoscopy has long been the method of choice for foreign body removal but is now being replaced by flexible bronchoscopy which offers reduced trauma and the ability to access distal bronchial regions. In the presented study we assessed the patients who underwent flexible bronchoscopy for foreign body removal in our clinic.Methods:We reviewed the records of 20 patients who underwent flexible bronchoscopy due to suspected foreign body aspiration and had a foreign body removed in our clinic. Patients were analyzed in terms of sociodemographic data, foreign bodies removed, method of foreign body removal, foreign body location and time to diagnosis.Results:Our study group included nine females and 11 males. The removed foreign body was organic in 19 of the 20 patients and inorganic in one patient. Hard organic food, such as hazelnuts, peanuts, seeds, almonds, and raw corn kernel were identified in 12 patients, a piece of fishbone in one patient and a piece of gelatin in another. The pieces of soft organic food identified were apple in one patient, egg in one patient, and boiled corn kernel in one patient and removed by suction. The foreign body was removed using forceps in nine patients, and a basket was used successfully in seven patients.Conclusion:Foreign bodies can be removed with minimal complication using flexible bronchoscopy, basket, and forceps in children.

Assessing The Quality of Life Among Older Adults Having Oral Health Problems

Oral health refers to the health of the oral cavity of an individual. Oral health is the most important part of general healthcare. The oral cavity or mouth make a major part of human body and considered to be the beginning of gastrointestinal and respiratory systems. The concept of Oral Health-Related Quality of Life (OHQoL) is focused on the idea that oral health issues can harm a person's self-esteem and self-image, create other health problems, hinder social contact, and cause pain, stress, and sadness. Objective: To assess the Quality of Life (QoL) among older adults having oral health problems. Methods: A Cross-sectional study was carried out from ‘Heaven Old-Age home’, Ferozepur Road, Lahore. Middle age to older adults aged between 45 to 80 years suffering from oral health problems were selected through a non-probability convenient sampling technique, and the sample size of 100 was enrolled. Participants were assessed through a self-constructed questionnaire. The data was analyzed by SPSS version 21.0. Results: Out of 100 participants, 45 were males while 55 were females while 96 participants were married. Socioeconomically, 72 participants belonged to the middle class in which 67 participants were educated, while 33 were uneducated. Result showed that 39 felt almost inability of chewing, 51 felt uncomfortable eating, 61 were feeling difficulty in biting hard food, and 54 were feeling difficulty while taking a big bite. Moreover, 77 were feeling difficult or restricted smiling, 74 were feeling difficulty in relaxing while 71 were feeling tense, and 83 were feeling irritable. 75 were embarrassed because of oral issues. However, 65 had pain in the mouth while 35 did not. 68 individuals had history of toothache in the previous 12 months, while 32 had not. Conclusion: It was concluded that there is an association between quality of life and oral health. Older adults face problems in chewing and swallowing food, feel pain while chewing or biting the food, and face nutritional deficiencies affecting their quality of life.

Eating Advice for People Who Wear Dentures: A Scoping Review.

Objective: A scoping review of available advice to address eating problems experienced by people who wear dentures was conducted in accordance with the PRISMA statement. The objective was to identify and map type, volume, and content of the available eating advice. Methods: Medline, CINAHL, and grey literature databases and Google were searched. Relevant content pertaining to study type, peer-review vs. grey literature, country of origin, advice content, and methods to evaluate effectiveness was mapped. Results: Of the 4591 records identified from peer-reviewed literature, 56 full papers underwent duplicate screening, resulting in 26 papers (from Germany (n = 1), Europe (n = 1), India (n = 2), Japan (n = 7), UK (n = 6), USA (n = 6), or other (n = 3)) being included in the review. These yielded 18 different items of relevant eating advice. Of the 258 screened websites, 63 were included, yielding 30 different items of eating advice. The most-cited advice was to eat soft food and avoid hard and sticky food, cut food into bite-sized pieces, and chew on both sides of the mouth and chew slowly and thoroughly. The identified advice was not supported by reference to peer-reviewed evidence. Advice included some conflicting messages and some advice was non-compliant with authoritative nutritional advice (e.g., avoid red meat, take a vitamin supplement). Conclusion: There is support for providing eating advice at the time of denture provision. A broad range of advice based on clinical experience to support people who wear dentures to overcome the functional limitations exists. However, the efficacy of this advice in improving diet and eating experience has not been tested.

Septic Cavernous Sinus Thrombosis Caused by Dental Infection

Purpose: We report a case of bilateral septic cavernous thrombosis caused by a dental infection.Case summary: A 58-year-old male was transferred to our hospital because of left-sided proptosis and eyelid swelling. The patient had fever and left temporal headache, which did not respond to oral and intravenous antibiotics. After experiencing a tooth injury while chewing hard food 3 months ago, the patient developed toothache and swelling around the tooth for which he did not take any treatment. The patient had left eyelid edema, ptosis, chemosis, and conjunctival congestion. The left eye movements were limited in all directions. Brain magnetic resonance imaging showed dilatation and thrombosis of the left superior ophthalmic vein and thrombosis of bilateral cavernous sinuses. The patient was treated with systemic antibiotics and anticoagulants. The blood culture showed growth of Parvimonas micra and Dialister Pneumosintes, which are common causes of dental infection.Conclusions: Septic thrombosis of the cavernous sinus and superior ophthalmic vein thrombophlebitis can occur due to the spread of dental infection. Prompt diagnosis and treatment are important for rapid resolution of symptoms and good prognosis.

Effects of textured food masticatory performance in older people with different dental conditions

BackgroundPhysiological deterioration (aging, poor dental status, and reduced tongue pressure) makes chewing difficult. This study aimed to investigate the chewing patterns of older people with or without dentures, evaluate the textural and masticatory properties of texture-modified radish Kimchi, and investigate the correlation between dental status and tongue pressure. Additionally, differences in the subjective–objective concordance of texture-modified Kimchi were investigated using the preference test.MethodsThis study included 32 Korean women aged between 65 and 85 years. Masticatory behavior was recorded by electromyography, and tongue pressure was measured using the Iowa Oral Performance Instrument. A preference test, with hardness as the relevant textural property, determined the participants’ preferences among the test samples (food with a homogeneous structure—radish Kimchi). To assess preference differences, a questionnaire suitable for older people was designed. The preference for cooked radish Kimchi with various blanching times based on overall acceptability and self-reporting of preference was investigated to develop elderly-friendly food. The subjective scores indicated whether the sample (radish Kimchi) was hard or soft based on the chewing ability of the participants. Dental status, muscle activities, and tongue pressure were considered for the food design with optimized texture. The relationship between subject score and mastication properties were examined using multiple regression analysis.ResultsThe number of chews and chewing time increased with hardness, significantly activating the masseter and temporalis muscles. The evaluation of masseter muscle activity, particularly for level-6 radish Kimchi, showed that older people with complete dentures chewed less actively than those with natural teeth (p < 0.05). The older people with natural teeth (18.94 ± 10.27 kPa) exhibited higher tongue pressure than those with complete dentures (10.81 ± 62.93 kPa), and the difference was statistically significant (p < 0.01). Older people preferred food with familiar tastes and textures. An association was found between the subjective hardness score and the objective hardness level. The perceived hardness intensity was linked to the chewing ability of the participant. Denture wearers exhibited a lower chewing ability, and at level 6, they perceived greater hardness of food than those with natural teeth.ConclusionsDeveloping food with a modified texture can bridge the gap between physiological and psychological aspects of food texture; texture-modified radish Kimchi, with limited blanching time, may be favorable for older people.

Texture Modification of 3D-Printed Maltitol Candy by Changing Internal Design

The purpose of this study is to show more diverse texture modifications by changing the material of a food 3D-printed structure conducted only with soft materials (in this case, potatoes and chocolate) to a hard material (in this case, maltitol here). However, unlike previous 3D-printed food materials, sweetener materials such as sucrose and maltitol are sensitively caramelized at a high melting temperature. As such, there is no commercialized printing equipment. Therefore, a printing process experiment was conducted first in this case. To do this, a high-temperature syringe pump-based extrusion device was designed, and process tests according to the temperature and environment were conducted. An assessment of the internal structural changes according to the infill patterns and infill percentages was conducted based on the acquired process conditions. The texture strength increased as the infill percentage increased. Depending on the infill patterns, the texture strength increased in the order of the Hilbert curve, honeycomb, and rectilinear samples here. As a result, a change in the texture strength was determined through a change in the internal structure of a hard food material using 3D printing, which showed a wider range of change than in conventional soft food materials.

The Influence of Food Tourism Experience on Revisit Intention

With the advent of the experience economy and the change of tourists' consumption concept, tourists pay more and more attention to the experience process of tourism, and the food experience has become an important factor for many tourists to choose tourism destinations. Based on this, this paper took Chengdu Jianshe Road as an example, carried out a combined online and offline questionnaire survey on Chengdu Jianshe Road tourists, and adopted SPSS 26 software to conduct factor, correlation and regression analysis to explore the effect of food experience on land revisit intention. First, tourists' evaluation indicators of Chengdu Jianshe Road can be divided into four dimensions: food characteristics, soft and hard conditions, food culture, and price level, which are generally positive. There was no significant correlation between revisit intentions (P&lt;0.05); in addition, through the exploration on the relationship between gourmet tourism experience and revisit intentions, it was found that food characteristics had a significant positive impact on revisit intentions (β=0.715, p &lt; 0.01), and has the greatest influence. In theory, this paper innovatively incorporates the exploration of food tourism experience as a core variable into the study of revisit intention, and provides relevant suggestions for future food research. In practice, this research has important reference significance for the marketing and development of food tourism destinations.

Dietary fatty acid patterns and risk of oesophageal squamous cell carcinoma.

BackgroundTo characterize and examine the associations between dietary fatty acid intake patterns and the risk of oesophageal squamous cell carcinoma (ESCC).MethodsA total of 422 patients and 423 controls were recruited. Dietary fatty acids were entered into a factor analysis. Multivariable logistic regression and restricted cubic spline were used to evaluate the risk of ESCC specific for different dietary fatty acid patterns (FAPs). A forest plot was applied to show the association between FAPs and ESCC risk after stratification by lifestyle exposure factors (tobacco smoking, alcohol drinking, pickled food, fried food, hot food, hard food).ResultsThe factor analysis generated four major fatty acid patterns: a medium- and long-chain SFA (MLC-SFA) pattern; an even-chain unsaturated fatty acid (EC-UFA) pattern, a saturated fatty acid (SFA) pattern and an n-3 long-chain polyunsaturated fatty acid (n-3 LC-PUFA) pattern. In the multivariate-adjusted model, the odds ratios (ORs) with 95% confidence intervals (CIs) of ESCC were 2.07 (1.31, 3.26) and 0.53 (0.34, 0.81) for the highest versus the lowest tertiles of the EC-UFA pattern and n-3 LC-PUFA pattern, respectively. The MLC-SFA and SFA patterns were not associated with ESCC. An association between FAPs and ESCC risk after stratification by lifestyle exposure factors was also observed.ConclusionsOur study indicates that the EC-UFA pattern and n-3 LC-PUFA pattern intake are associated with ESCC, providing a potential dietary intervention for ESCC prevention.

Detection of cracked teeth using a mechanoluminescence phosphor with a stretchable photodetector array

Cracked tooth syndrome (CTS) is an incomplete fracture of a human tooth that commonly arises from chewing hard foods. Although it is a very common syndrome, CTS is often difficult to diagnose owing to the common small size of tooth cracks. Conventional techniques for the detection of cracks, such as transillumination and radiographic methods, are inaccurate and have poor imaging resolution. In this study, we devise a novel method for the in vivo detection of tooth microcracks by exploiting the mechanoluminescence (ML) phenomenon. ZrO2:Ti4+ (ZRT) phosphor particles are pasted onto suspected regions of tooth cracks and emit cyan-colored light as a result of masticatory forces. Then, a stretchable and self-healable photodetector (PD) array laminated on top of the phosphor particles converts the emitted photons into a photocurrent, which facilitates the two-dimensional mapping of the tooth cracks. Because of the high photosensitivity of the PD, intense ML and small size of ZRT phosphor particles, it is possible to image submicron- to micron-sized cracks with high resolution. Furthermore, the uniqueness of this technique over the conventional techniques stems from the application of a simple optical phenomenon, i.e., ML, for obtaining precise information regarding the locations, depth, and length of tooth cracks.

Inclusion body myositis and dysphagia. Presentation, intervention and outcome at a swallowing clinic.

This study reviewed patients with inclusion body myositis who were referred for assessment of dysphagia at a tertiary swallow clinic. It describes symptoms at presentation, imaging and management strategies. A retrospective review of electronic patient records was performed between 2016 and 2020. Twenty-four patients were included, with a mean age of 72 years. Baseline modified Sydney Swallow Questionnaires identified problems with hard or dry food, food sticking, and repeated swallowing. Twenty-two patients had a Reflux Symptom Index score that could indicate significant reflux. Video swallow identified specific problems, including tongue base retraction (96 per cent) and residual pharyngeal pooling (92 per cent). Seven patients (30 per cent) had features of aspiration on imaging despite a median penetration-aspiration scale score of 2. Four patients received balloon dilatation, and two patients underwent cricopharyngeal myotomy. This study helped to profile features of dysphagia in patients with inclusion body myositis. More evidence is needed to determine the most effective management pathway for these patients.

The effects of unilateral posterior crossbite toward the superficial masseter and anterior temporalis on muscle activity during mastication: A surface electromyographic study

Background: Adapted patterns of mastication caused by unilateral posterior crossbite require early orthodontic treatment to prevent permanent muscle change. Stable orthodontic results depend on the harmonious contraction of the occlusion and masticatory muscles. Purpose: Using surface electromyography, this study aimed to analyse the effects of unilateral posterior crossbite on the superficial masseter as well as anterior temporalis muscle activity on the crossbite and non-crossbite sides during chewing soft and hard foods. Methods: A cross-sectional study was conducted on 20 subjects with at least two posterior teeth who had a unilateral posterior crossbite without mandible shifting. Surface electromyography was used to measure activity amplitudes for the superficial masseter and the anterior temporalis muscles while chewing soft and hard foods. An independent t-test was used to determine the mean difference between chewing soft and hard foods through the superficial masseter and anterior temporalis muscles. Results: Results showed a significant difference in amplitude mean between crossbite and non-crossbite sides of the superficial masseter and anterior temporalis muscles with both soft and hard food chewing (p &lt; 0.05). The study also revealed a decrease in the activities of superficial masseter and anterior temporalis muscles when masticating soft and hard foods on the crossbite sides as compared to the non-crossbite sides. Conclusion: A unilateral posterior crossbite results in a decrease in the superficial masseter and the anterior temporalis muscle activity when masticating both soft and hard foods on the crossbite side.

Development and characterization of standardized model, solid foods with varying breakdown rates during gastric digestion

Standardized, model solid foods were developed with varying initial hardness and breakdown rates during in vitro digestion. One class of model foods was based on the Standard American Diet, with strong and weak gel versions created by modulating pH. Another class was developed using whey protein hydrogels, with strong and weak gel versions produced by addition of pectin. The initial hardness of the model foods ranged from 6.2 ± 1.0 N (whey protein weak gel) to 56.2 ± 5.7 N (whey protein strong gel; p < 0.05), and softening half-times ranged between 58 ± 5 min (standard diet weak gel) and 775 ± 82 min (whey protein strong gel; p < 0.05). The model foods were placed into distinct classes according to the Food Breakdown Classification System. These model foods could help future studies develop relationships between food physical property changes during digestion and variables such as gastric emptying and satiety. • Model foods were developed based on the Standard American Diet, or using whey protein hydrogels (2 classes). • Two model foods in each class were developed that differed in initial hardness and softening half-time. • The initial hardness of model foods varied between 6.2 N and 56.2 N. • The softening half-time of model foods during in vitro oral and gastric digestion ranged from 58 min to 775 min. • The model foods were categorized according to the Food Breakdown Classification System.

Association between Oral Frailty and Physical Frailty among Rural Middle-Old Community-Dwelling People with Cognitive Decline in Taiwan: A Cross-Sectional Study.

This cross-sectional study was conducted to clarify the association between oral frailty (OF) and physical frailty (PF). In total, 308 Taiwanese middle-old (75–84 years) community-dwelling people with cognitive decline were recruited from random rural community health care centers. Eight items were considered for the evaluation of their OF status. The Study of Osteoporotic Fracture index was used for frailty assessment, which revealed that 22% of the participants had PF. In an adjusted model, PF was significantly associated with the OF subdomains of difficult to eat hard food (p = 0.009), choking (p = 0.008), denture use (p = 0.008), and inability to chew hard food (p = 0.001); and high risk of OF (OR = 3.03; p = 0.002). After eight steps with elimination of the least significant independent variable, age (p= 0.008), self-reported health status of fair (p = 0.000) and poor (p = 0.000), mild cognitive impairment (p < 0.001) and denture use (p = 0.011) were found to be the indispensable predictors for PF. The logistic regression model with 5 indispensable variables had a predictive value of 78.2%. Longitudinal analyses are needed to examine whether OF is a risk factor for PF onset.

Función masticatoria según índice de masa corporal. Parte I: análisis cinemático utilizando diferentes texturas de alimentos

Introduction: Chewing is a learned orofacial function, important in the nutrition process of most mammals. It has been described that it can vary according to the characteristics of the individuals and the characteristics of the food. The aim of this study was to compare the kinematic cha-racteristics of mastication in subjects with different body mass index (BMI), including foods of different hardness in the analysis. Material and Methods: A cross-sectional observational study was con- ducted. The mastication of 3.7 g of peanut (soft food) and 3.7 g of carrot (hard food) was compared among three study groups formed according to BMI: normal weight (BMI 18.5-24.9), overweight (BMI 25-29.9) and obese (BMI ?30); each with 7 participants. The kinematics of the masticatory movement were assessed with a 3D Electromagnetic Articulograph, the characteristics analyzed were number of masticatory cycles, masticatory frequency, speed and area of the cycles. Results: No significant differences were noted among the study groups for the number of masticatory cycles, frequency or speed in the two foods studied. It was observed that when chewing carrot, the horizontal area of the masticatory cycles was significantly larger in the obese than in the overweight group. However, when chewing peanuts, this parameter did not present significant differences among the different groups. A comparison of the characteristics of mastication of the two foods revealed that the carrot chewing presented a significantly greater masticatory frequency and speed than the peanut chewing. Conclusion: This study demonstrated that food hardness influences the kinematic characteristics of mastication more than BMI, noting that hard foods are masticated faster and more frequently than soft foods and that masticatory frequency tends to increase with BMI.

Experimental assessment of the relationship between diet and mandibular morphology using a pig model: New insights for paleodietary reconstructions.

Dietary habits exert significant selective pressures on anatomical structures in animals, leading to substantial morphological adaptations. Yet, the relationships between the mandible and diet are still unclear, raising issues for paleodietary reconstructions notably. To assess the impact of food hardness and size on morphological structures, we used an experimental baseline using a model based on the domestic pig, an omnivorous mammal with bunodont, thick-enameled dentition, and chewing movements similar to hominids. We hypothesized that the consumption of different types of seeds would result in substantial differences in the morphology of the mandible despite similar overall diets. The experiment was conducted on four groups of juvenile pigs fed with mixed cereal and soy flours. The control group received only flours. We supplemented the four others with either 10 hazelnuts, 30 hazelnuts, 30% barley seeds, or 20% corn kernels per day. We investigated the shape differences between the controlled-fed groups using three-dimensional geometric morphometrics. Our results provide strong evidence that the supplemental consumption of a significant amount of seeds for a short period (95 days) substantially modify the mandibular morphology of pigs. Our analyses suggest that this shape differentiation is due to the size of the seeds, requiring high and repeated bite force, rather than their hardness. These results provide new perspectives for the use of mandibular morphology as a proxy in paleodietary reconstructions complementing dental microwear textures analyses.