Hard Food Research Articles

Illness perceptions amongst individuals with dental caries.

To assess individuals' perception of dental caries, in order to explain how illness representations might influence their coping with the disease. Cross-sectional questionnaire study. 520 consecutive patients (aged ≥18 years) of the General Dentistry Clinic at Universidad Cooperativa de Colombia, Pasto, Colombia who had experienced dental caries. Illness perception of dental caries was assessed using the Illness Perception Questionnaire Revised (IPQ-R). The most frequent self-reported symptoms associated with dental caries were "toothache" (56.2%), "tooth sensitivity" (53.8%) and "mild to sharp pain when eating or drinking" (51.2%). The dimensions of illness perception were related to socio-economic status (SES). Symptoms of "loose or separating teeth" and "pus in your tooth" were associated with dental caries by low SES participants, while "bleeding while brushing, flossing or eating hard food" and "mild to sharp pain when eating or drinking something sweet, hot or cold" were related more to higher SES. Perceptions of caries were related to socioeconomic status. Interventions to promote health literacy in order to improve the capacity to obtain, process and understand basic oral health information could increase an early detection of caries.

Brief communication: Dental microwear and diet of Homo naledi.

A recent study of dental chipping suggested that Homo naledi teeth were exposed to "acute trauma" on a regular basis during life, presumably from the consumption of grit-laden foods. This follows debate concerning the etiology of dental chips in South African hominin teeth that dates back more than half a century. Some have argued that antemortem chips result from consumption of hard foods, such as nuts and seeds or bone, whereas others have claimed that exogenous grit on roots and tubers are responsible. Here we examine the dental microwear textures of H. naledi, both to reconstruct aspects of diet of these hominins and to assess the possibility that hard foods (gritty or otherwise) are the culprits for the unusually high antemortem chip incidence reported. We made high-resolution replicas of original molars and found that ten individuals preserve antemortem wear. These were scanned by white-light scanning confocal profilometry and analyzed using scale-sensitive fractal analysis. Resulting data were compared with those published for other fossil hominins and extant non-human primates. Our results indicate that H. naledi had complex microwear textures dominated by large, deep pits. The only known fossil hominin with higher average texture complexity is Paranthropus robustus, and the closest extant primates in a comparative baseline series appear to be the hard-object feeder, Cercocebus atys, and the eurytopic generalist, Papio ursinus. This study suggests that H. naledi likely consumed hard and abrasive foods, such as nuts or tubers, at least on occasion, and that these might well be responsible for the pattern of chipping observed on their teeth.

Comparison between masticatory index and mixing index among complete denture wearers and associated factors: A multivariate analysis

Statement of problemMasticatory performance is an important and complex multifactorial process in clinical practice. An exploration of the relationships and effects of the associated factors is lacking. PurposeThis clinical survey compared masticatory efficiency (mixing index) with perceived masticatory ability (masticatory index) among complete denture wearers and sought to clarify the relationship between these indices and other factors. Material and methodsThe study consisted of 58 complete denture wearers (37 men, 21 women) ranging between 37 and 80 years of age. Participants were interviewed and examined clinically. The perceived masticatory ability of participants regarding 15 types of Sudanese food was evaluated. The degree of mixing of a 2-colored chewing gum was used to measure masticatory efficiency. Multiple regression and structural equation modeling analyses were used to assess the association between both indices and other related factors. ResultsMost of the complete denture wearers could eat soft foods easily but found it difficult to eat hard foods and avoided them. No significant differences in masticatory efficiency could be observed regarding sex or age. Values of the mixing index ranged from 13 (well-mixed colors) to 34 (poorly mixed). Perceived masticatory ability was significantly associated with previous denture experience and the duration of denture wearing (P=.01). Masticatory efficiency was significantly associated with denture quality (P=.001) and with perceived masticatory ability (P=.004). ConclusionsA significant association was noted between denture quality and masticatory performance. A significant association was also observed between perceived masticatory ability and masticatory efficiency, and both can be used to evaluate masticatory performance among complete denture wearers.

Swallowing Exercises: Will They Really Help Head and Neck Cancer Patients?

Purpose:The work was a comparative study, the aim of which is to evaluate the impact of swallowing exercises on swallowing problems among head and neck cancer patients (HNCPs) after CRT.Methods:The sample of 60 HNCPs was equally divided into control and study groups. The investigators met all patients 3 times (before, during and after CRT); swallowing ability was assessed using the Sydney Swallowing Questionnaire (SSQ). The University of Texas, MD Anderson Cancer Center Swallowing Exercise Protocol was explained and demonstrated by the investigators to the study group. All tools used were translated into Arabic. Data analyses were carried out using the statistical package for social sciences (SPSS), program version 20.Results:Most of the patients from both groups experienced mild dysphagia during the 1st visit. By the 3rd visit, severe dysphagia (to thin and thick liquids, and soft and hard food) was higher in the control group (73.3%) compared to the study group (26.7%). By the third visit there was statistically significant difference between both groups in swallowing thin liquids (p = 0.01), as well as thick liquids (p = 0.01). At the 1st visit, there was no significant difference regarding swallowing soft food (p = 0.24), hard food (p = 0.17), dry food (p = 0.89) and swallowing Saliva (p = 0.28). While by the 3rd visit, there was significant difference between control and study groups in all parameters.Conclusions:Adequate prevention and treatment of dysphagia, with use of swallowing programs, is essential to plan a complete therapeutic programme.

Interaction between Risk Factors and Gastric Cancer: A Population-Based Case-Control Study in a High Risk Chinese Area

Introduction: An extremely high prevalence of gastric cancer (GC) was observed in Xianyou County, the Southeastern of China, yet it remains unclear how interaction of environmental factors affects the GC risk in this area.Methods: A population-based case-control study was conducted during March 2013 and January 2017 in Xianyou County. All newly diagnosed patients with GC were compared with healthy controls matched (1:1) by sex, age (± 3 years) and place of residence.Results: A total of 622 cases of GC and 622 matched healthy controls were included. Participants who consumed pickled vegetables and had a preference for hard solid food had the highest risk of GC (adjusted OR=12.42, 95% CI: 7.56-20.41) compared to individuals who did not have such food patterns. Increased GC risk was also observed among those who consumed pickled vegetables but not drink tea (adjusted OR=6.88, 95% CI: 3.74-12.66), compared to those drinking tea but did not consume pickled vegetables. Furthermore, participants who did not consume tea but were exposed to pesticides during farm work also had 2.50 times (95% CI: 1.30-4.80) higher risk of GC risk compared to those had tea consumption but were not exposed to pesticides. No statistically significant interactions were observed for pesticide exposure, smoking, beef or pork consumption, fruit consumption, chronic atrophic gastritis and family history of any cancer in relation to GC.Conclusion: Strong synergistic effects in raising the risk of GC were seen between pickled vegetables consumption and hard solid food preference, as well as between pickled vegetables consumption and not drinking tea.

Effect of different complete dentures base materials on muscular activity

Aim: The purpose of this study was to examine changes in relative electromyographic (EMG) activities of temporal and masseter muscles after relining the dentures with soft,hard and conventional heat cured based denture liners.Materials and Methods: Conventional complete dentures were fabricated for 30 edentulous patients. They were divided into three groups. Group I including patients received denture relined with soft liner. Group II including patients received denture relined with hard liner and Group III including patients received dentures relined with conventional heat cured relining material Electromyography of the masseter and temporalis muscle was recorded during eating carrot as hard food and banana as soft one. The records were measured after one, three and six months. Data was analyzed using Statistical ANOVA test to compare between muscle activities of the three groups Duncan’s test was used for pair-wise comparisons to determine the differences between means.Results: Complete denture relined with soft liner showed significant difference in masseter and temporalis muscles activities as compared with the two other groups.Conclusion: Complete denture relined with soft liner show better effect on masseter and temporalis muscles activity and patient satisfaction.

A Preliminary Investigation into the Dietary and Oral Practices Associated with Fractured Teeth and Prostheses in a Trinidadian Population.

Objectives:This preliminary study seeks to determine the relationship between fractured teeth, restorations, prostheses, and specific dietary practices.Methodology:Anonymous questionnaires were randomly distributed to a convenience sample of Trinidadian adults at various locations around the country, after gaining consent. Data were analyzed using the software; Statistical Package for the Social Sciences for significant associations between various types of food and broken teeth or prosthesis using odds ratios.Results:Three hundred questionnaires were completed. Seventy-five percent of the patients preferred crunchy or hard foods and 51% of the respondents liked crushing bones, mostly chicken bones. It was observed that respondents with a dietary preference for fried whole chana, split chana, crab, and sugarcane were significantly associated with broken dentures. Respondents eating whole chana also had a significant association with broken teeth and broken dentures. Associations were found between some dietary preferences, ethnicities, and age groups.Conclusions:Significant associations between age, ethnicity, sex, and certain dietary practices and habits were found. There also appears to be a significant relationship between patients with fractured teeth, restorations, and prostheses with certain dietary preferences.

Nutrition and orthodontics

Orthodontic patients avoid many types of food, particularly fruits, raw vegetables, and other hard and tough foods, as they cannot chew these properly because of pressure sensitivity of the teeth in the initial 3–5 days period after routine. As a result, such individuals consume significantly less proteins and other key nutrients, fiber, calcium, nonhem iron, and some vitamins. This article presents an overview of the relationship between diet and orthodontic treatment. The nutritional guidelines to obtain good oral and general health in orthodontic patients are discussed.

A Self-Reported Association between Temporomandibular Joint Disorders, Headaches, and Stress.

Aims and Objectives:Temporomandibular joint disorder (TMD) is an umbrella term for a number of conditions in the area of the joint, temple, and masticatory system. Many of those with TMD also suffer from headaches and anxiety. The aims and objectives of this study were to determine if there exists an association between the Diagnostic Criteria of TMD (DC/TMD) symptom questionnaire and report of headaches as well as stress.Materials and Methods:A cross-sectional study was implemented via the use of the DC/TMD symptom questionnaire and the perceived stress scale (PSS). This was distributed conveniently among dental students in a multi-dental school setting in Riyadh, Saudi Arabia, and was completed by 152 dental students. Odds ratios, Chi-square, and their corresponding 95% confidence intervals are reported. Statistical significance was set at P ≤ 0.05.Results:Those who ticked yes for pain on the TMD pain screener for pain with chewing hard or tough food, pain on mouth opening and lateral excursion, and pain with jaw habits as parafunction were at an odds risk from twice to thrice as likely to experience headaches. Similarly, those with poor coping skills on the PSS were more likely to have headaches (P = 0.002). Likewise, positive answers on the screener and symptom questionnaire were relevant with higher stress scores on the PSS.Conclusion:This study clarifies and reiterates the intertwined power of both stress and headaches; the former being a role player in TMD progression and the latter its product. TMD is unfortunately on the rise; it should not be brushed off as a nuisance. A multidisciplinary approach in diagnosis and treatment of both TMD and headaches by a team of orofacial pain specialist, neurologist, psychiatrist and/or psychologist, and physical therapists to untangle the deceiving presentation of both conditions would not only provide a more favorable prognosis but also improve cost and time expenditures.

Change in Autonomic Nervous Activity during Ingestion of Soft Food in Older Nursing Home Residents.

The deterioration in masticatory function often seen in older adults rules out the consumption of hard foods, while a common decline in autonomic nervous response often observed in older adults may result in maladjustment to environmental stresses. The purpose of this study was to investigate whether autonomic nervous activity in older adults increased during the mastication of soft foods compared to at rest. The participants comprised 9 volunteer nursing home residents aged 78 to 100 years. All consumed soft rice as a grain dish and coarsely chopped food as side dishes. The coefficient of variation of R-R intervals (CVRR) and high-frequency (HF) power on electrocardiograph (ECG) served as indices of parasympathetic nervous activity, while the low-frequency (LF)/HF ratio served as an index of sympathetic nervous activity. Total power, reflecting the level of autonomic nervous activity, was also measured. We measured autonomic nervous activity while nursing home residents were eating lunch. HF was 3,457.4±3,037.5 ms2 at rest and 4,085.1±3,697.7 ms2 during mastication. The CVRR was 26.8±16.9% at rest and 26.1±16.1% during mastication. No significant difference was observed in HF or CVRR. On the other hand, the LF/HF ratio was 0.77±0.24 ms2 at rest and 31.0±3.77 ms2 during mastication (p=0.011). A significant difference was observed in the LF/HF ratio between the resting and masticating conditions. Total power was 6,244.1±5,752.5 ms2 at rest and 8,417.7±7,266.4 ms2 during mastication (p=0.038). A significant difference was also observed in total power between resting and masticating conditions. These results suggest that mastication of soft foods stimulates autonomic nervous activity in older adults. In conclusion, autonomic nervous activity increased during chewing soft foods compared to that during the resting level in older adults.

Effects of loading on chondrocyte hypoxia, HIF-1α and VEGF in the mandibular condylar cartilage of young rats.

To investigate hypoxia-inducible factor 1-alpha (HIF-1α) and vascular endothelial growth factor (VEGF) expression under altered loading, and to explore the relationship between loading and hypoxia in the mandibular condylar cartilage of young rats. Eighty Sprague-Dawley rats. The reduced loading group was fed soft food, and their incisors were cut to avoid occlusal contact. The increased loading group was fed hard food and had forced jaw-opening. Ten rats from each group (n=10) were sacrificed at 12, 24, 48, and 96hours after initiation of the experiment. Pimonidazole hydrochloride (Hypoxyprobe-1, HP-1) was used as a hypoxia marker to confirm the hypoxic state. Hypoxic chondrocytes as indicated by HP-1, HIF-1α and VEGF protein expressions were recognized by immunohistochemical detection. HIF-1α and VEGF mRNA expressions were detected by semi-quantitative RT-PCR. Hypoxyprobe-1 was confined in the upper layers of cartilage, and was most strongly expressed in the weight-bearing area of TMJ at 12 and 96hours. Staining of HIF-1α and VEGF was most strongly expressed in the chondrocytes of the fibrous and proliferative layer at all time points. Furthermore, expressions were also displayed in the hypertrophic and calcified layers at 48 and 96hours. The expressions of HIF-1α and VEGF mRNA were higher in the increased loading group than in the reduced loading group at 48 and 96hours (P<.05). Mechanical loading seems to directly induce weight-bearing area hypoxia followed by new vessel formation, which indicates that these factors are related and important for the development of cartilage.

Self-Reporting Questionnaire on Gingival Bleeding Among Dental Students at University of Sulaimani

Objective: Gingival bleeding during tooth brushing and eating is a clinical sign of gingivitis and periodontitis, or infrequently due to some associated systemic conditions or diseases such as vitamin C deficiency and blood diseases. Periodontal diseases are the six most prevalent conditions affecting human kind that are associated with plaque. The aims of this study were to determine self-experience gingival bleeding among dental students and their knowledge toward etiology, pathogenesis and management of gingival bleeding.&#x0D; Methods: This questionnaire-based study was conducted on dental students, the questioner form included experience of gingival bleeding among students, their family experience of gingival bleeding, students’ view to address this issue by either stopping tooth brushing and/or other oral hygiene measures or by visiting a dentist to manage the problem. Furthermore, the questioner examined students’ knowledge on cause of bleeding and factors (systemic and habits) that associated with it.&#x0D; Results: Three hundred students answered the questioner and the frequency of gingival bleeding were: 15.7% experienced frequent gingival bleeding, 51.6% showed rare gingival bleeding and 32.6% with no experience of gingival bleeding. More than 44% of the students answered that at least one of their family member experienced gingival bleeding. Mechanical stimuli such as tooth brushing were the cause of gingival bleeding of 66.3% participants. Gingival bleeding was also reported by eating hard food like apple (9%) and early morning gingival bleeding (5.3%). After bleeding, 16.7% visited the dentist and 19.3% of students stopped tooth brushing. Around half of the participants related gingival bleeding to the gingival disease itself, whereas, the other half related to other diseases.&#x0D; Conclusions: Gingival bleeding is prevalent among dental students and their family members. Student’s knowledge of the cause of gingival bleeding was limited. Furthermore, students’ reaction to manage bleeding gingiva is controversial.

DESCRIPTION OF DENTAL CARIES AND EFFECTS OF FOODS ON TOOTH DESTRUCTION IN SKULLS OF PAWON MAN

The skeleton of Pawon Man’s that lived in Mesolitic era aged 5,660±170 BP - 9,500± 200 BP (Before Present) years before Christ (BC) has been used for forensic odontology research. However, there has not been any research on dental caries of Pawon Man. The aim of this research was to describe the dental caries in skulls of Pawon Man. The type of the research was descriptive by using purposive sampling. The samples were from four Pawon Man skulls and their teeth. The research was conducted by using clinical examination. All aspects were recorded, collected and presented in tabular form. The result shows that 12.5% of the samples from 32 teeth of skulls of Pawon Man I, III, IV and V had experienced dental caries. Clinical examination shows presence of dental caries in samples of Pawon Man III of permanent mandibular third molar tooth of region 4(48) in lingual area and buccal lesion of lower left third molar (38). In Pawon IV, lingual lesion of lower left permanent second molar (37) and in lower left permanent third molar (38). All lesions are only in enamel which is code 1 according to ICDAS code. In conclusion, the dental caries in skulls of Pawon Man was low due to their low sugar diets from fruits and sugar-rich plants (fructose sugars). Consumption of hard foods and evidence of presence of animal teeth and mollusks had contributed to the higher percentage of dental attrition compared to dental caries. Keywords: dental caries, clinical, pawon man

Prevalence of tooth wear and its associated risk factors among industrial workers in Daman, India: a cross-sectional study

Background: Tooth wear is an ever increasing problem. Therefore, the aim of the present study was to assess the prevalence of tooth wear and its associated risk factors among industrial workers in Daman, India. Methods: This cross sectional study was conducted among 613 industrial workers selected using simple random sampling. The clinical assessment of tooth wear was done using tooth wear index (TWI) developed by Smith &amp; Knight. A specifically designed questionnaire was used to seek information on risk factors of tooth wear. Data were analyzed using Pearson’s chi-square test, ANOVA and a multiple logistic regression model. Results: The overall prevalence of tooth wear was found to be greater in mandible (86.8%) as compared to maxilla (61.7%). In both maxilla and mandible, the most frequently affected teeth were incisors (55.8% and 83.7%) followed by canines (52.2% and 81.2%), pre molars (38.5% and 42.1%) and molars (37.8% and 38.8%). Among the risk factors, consumption of hard or acidic foods (p=0.01, OR=1.73) and use of hard toothbrush bristles (p=0.04, OR=0.04) in maxilla and clenching or grinding of teeth (p=0.01, OR=3.96) in mandible were significantly associated with tooth wear. However, work environment involving dust or acid gas was the only risk factor associated with tooth wear in both maxilla (p=0.004, OR=0.53) and mandible (p&lt;0.001, OR=0.35). Conclusions: There is a high prevalence of tooth wear among industrial workers. Thus, efforts should be made by dentists to increase awareness about tooth wear and plan a three-level prevention program based on analysis of risk assessment.

Dietary ecology of Pleistocene mammoths and mastodons as inferred from dental microwear textures

The Columbian mammoth (Mammuthus columbi) and the American mastodon (Mammut americanum) have traditionally been considered to have been ecologically distinct, with mammoths often characterized as cosmopolitan grazers or mixed feeders and mastodons as forest-dwelling browsers. However, these large-bodied proboscideans occupying temperate, often resource-limiting environments in Pleistocene North American would have necessitated a much wider range of resources. For the isolated pygmy mammoth (Mammuthus exilis) of California's Channel Islands, the resource-limited nature of its insular home may have exacerbated the need for consumption of a wide range of less-preferred resources. The goal of this study is to better understand the degree to which each of these taxa consumed tough and/or hard food items, including grass, leaves, and woody browse in their respective environments. To this end, we examined the dental microwear of Pleistocene mammoths and mastodons to address the following questions: 1) do mammoths and mastodons with known differences in diet (via carbon isotopes) have similar dental microwear attributes?, 2) do juvenile and adult mammoth and mastodons consume foods with similar textural properties?, and 3) did the Channel Islands mammoths consume food with similar textural properties as the mainland Columbian mammoths? Our results demonstrate that the mammoths and mastodons here examined ate foods with similar textural properties, despite consuming plants with disparate stable isotope values. These data suggest that mammoths and mastodons were generalists (in regards to dietary textures) and did not eat softer or tougher foods as juveniles. Further, the Channel Islands mammoths ate food items with more variable textural properties (including a greater incidence of hard foods) than Columbian mammoths from Texas. While more work is needed to assess the ubiquity of these results across time and space, collectively, these data suggest that extinct proboscideans are generalist feeders similar to extant elephants.

Using Electromagnetic Articulography to Measure Denture Micromovement during Chewing with and without Denture Adhesive.

PurposeTo study the effects of denture adhesive upon denture micromovements in three dimensions during the chewing of hard, sticky, and tough food items observed using a novel method involving an electromagnetic articulograph (EMA) speech research system.Materials and MethodsTen volunteers (mean age 60.9 ± 10.4 years) with fair‐ or poor‐fitting complete maxillary dentures were enrolled. Chewing experiments were conducted using two treatments (adhesive or no‐adhesive control) and three foods: carrots (hard), raisins (sticky), and processed meat stick (tough). Denture micromovement was measured through a novel application of a Northern Digital Wave EMA System. Three‐dimensional denture position was captured during mastication using three sensors embedded into a replica denture for each subject. Following individual characterization of a “home” reference position, the Euclidean Distances from Home (DfH) were calculated for each recorded sample of the chewing experiments. The DfH at each sample represented the denture movement for that 1/100th of a second of the activity. The DfH data were then summarized as the mean DfH, the maximum DfH, and total distance traveled by the denture. Several thresholds were also analyzed, including the percent of time that the DfH ≥1.5 mm, ≥2.0 mm, and ≥2.5 mm.ResultsWith adhesive treatment, the mean DfH of dentures during chewing was reduced by 26.8% for carrot, 30.3% for raisin, and 31.0% for meat stick, when compared with no‐adhesive treatment (p < 0.001 for all comparisons). Similar results were also seen for the maximum DfH and total distance travelled endpoints across foods. For the threshold endpoints, adhesive treatment was associated with a statistically significant reduction in denture micromovements at all three thresholds across foods. At the threshold of DfH ≥ 1.5 mm, adhesive treatment was associated with a reduction in micromovement by 61.6%, 56.2%, and 70.0% with carrot, raisin, and meat stick, respectively (p ≤ 0.004 for all comparisons).ConclusionsObservations of denture movement using the Wave EMA System were able to differentiate systematically between adhesive treatment and no‐adhesive treatment for denture micromovements during different chewing challenges. Use of adhesive was associated with statistically significant reductions in denture micromovements for hard, sticky, and tough foods as measured with both distance and threshold endpoints.

A comparison of feeding biomechanics between two parrotfish species from the Gulf of California

Parrotfish are amongst the most abundant teleost species in the Gulf of California, and yet their feeding ecology and the impact they have on the reef ecosystems in this region remain unknown. Here, a well-established computational model of jaw biomechanics in fishes (MandibLever 4.0) was used to simulate the mandibular dynamics during feeding of the two dominant reef-dwelling parrotfish species in the Gulf of California (Scarus ghobban and S. perrico), and to infer, to some extent, their potential ecological role. A total of 52 specimens were collected from six localities in La Paz Bay and the Los Cabos region between March and October 2015. The model predicted a greater jaw closing force and power in the bite of S. perrico, but a higher mandibular rotating velocity in S. ghobban. The calculated differences in their bite dynamics suggest that these two species may exploit different food resources, driven by food hardness. Moreover, the variation in their mandibular morphology and predicted feeding behavior might imply the presence in the Gulf of California of the two previously described functional groups found in reef-dwelling parrotfishes: excavators and scrapers. As an excavator, S. perrico would be functioning as one of the major agents of external bioerosion in the rocky reefs of the Gulf of California, whereas, as a scraper, S. ghobban would facilitate the reworking and hydrological transport of fine sediments. This work lays the foundation for future studies on the feeding ecology and impact of parrotfishes on the reefs of the Gulf of California.

Was Mesopithecus a seed eating colobine? Assessment of cracking, grinding and shearing ability using dental topography

Extant colobine monkeys have been historically described as specialized folivores. However, reports on both their behavior and dental metrics tend to ascribe a more varied diet to them. In particular, several species, such as Pygathrix nemaeus and Rhinopithecus roxellana, are dedicated seasonal seed eaters. They use the lophs on their postcanine teeth to crack open the hard endocarp that protects some seeds. This raises the question of whether the bilophodont occlusal pattern of colobine monkeys first evolved as an adaptation to folivory or sclerocarpic foraging. Here, we assess the sclerocarpic foraging ability of the oldest European fossil colobine monkey, Mesopithecus. We use computed microtomograpy to investigate the three-dimensional (3D) dental topography and enamel thickness of upper second molars ascribed to the late Miocene species Mesopithecus pentelicus from Pikermi, Greece. We compare M. pentelicus to a sample of extant Old World monkeys encompassing a wide range of diets. Furthermore, we combine classic dietary categories such as folivory with alternative categories that score the ability to crack, grind and shear mechanically challenging food. The 3D dental topography of M. pentelicus predicts an ability to crack and grind hard foods such as seeds. This is consistent with previous results obtained from dental microwear analysis. However, its relatively thin enamel groups M. pentelicus with other folivorous cercopithecids. We interpret this as a morphological trade-off between the necessity to avoid tooth failure resulting from hard food consumption and the need to process a high amount of leafy material. Our study demonstrates that categories evaluating the cracking, grinding or shearing ability, traditional dietary categories, and dental topography combine well to make a powerful tool for the investigation of diet in extant and extinct primates.

EFFECT OF TWO TECHNIQUES OF COMPLETE DENTURE CONSTRUCTION ON THE MUSCLE ACTIVITY AND OCCLUSAL LOAD

Objective: to evaluate the effect of two techniques of denture construction on the muscle activity using electromyography the occlusal load using T-scan.Materials and method: Twenty completely edentulous patients were selected and allocated into two groups: Group I: The upper and lower denture were processed in the usual manner and delivered to the patient. Group II: The upper waxed denture we processed only then remounted against the waxed lower denture any occlusal adjustment was done in the lower waxed denture then the processing the lower denture was performed - Electromyography recording were performed with the patient seated in relaxed upright position. -Electromyography recording device was used to evaluate the action potential of the masseter and anterior fibers of temporalis muscle. -The T-scan III was used for bite force measurement to detect the location, timing and magnitude of occlusal forces.Results: There was statistically significant difference between both groups during chewing soft and hard food diet for masseter and temporal is muscles. The highest mean differences muscle activity were recorded for patients received conventional denture while the lowest values recorded for patients received denture in muscle activity of group II.Conclusion: The Schlosser’s technique is considered as predictable methods of complete denture construction. The more harmonious occlusion result from this technique results in an improvement of the muscle activity and biting force.

Feather-Eating In Grebes: A 500-Year Conundrum

ABSTRACT Grebes are unique among birds in ingesting their own feathers. This behavior and the subsequent ejection of feathers as pellets have long puzzled ornithologists, who have tended to treat feather-eating and pellet-casting as independent behaviors rather than as complementary components of the digestive process. The diet of many grebes, including those with the most ancestral traits, is dominated by small invertebrates whose exoskeletons are resistant to digestion. Most birds eat grit to mechanically break down hard foods. Not so with grebes, which are chemical digesters. Feather-eating performs two main functions. The first is to retain food until it is fully digested; this is accomplished by a large feather bolus in the gizzard. The second, provided by a distinct group of feathers in the pyloric pouch, is to filter undigested or indigestible items from entering the intestine. Some of the gizzard bolus is probably regurgitated nightly, but the process is incomplete and undigested food can persist ...