scholarly journals Dental microwear texture gradients in guinea pigs reveal that material properties of the diet affect chewing behaviour

2021 ◽  
Author(s):  
Daniela E. Winkler ◽  
Marcus Clauss ◽  
Maximilian Rölle ◽  
Ellen Schulz-Kornas ◽  
Daryl Codron ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Guinea Pigs ◽  
Dental Microwear ◽  
Natural Habitats ◽  
Tooth Position ◽  
Posterior Tooth ◽  
Plant Feeding ◽  
Feeding Experiments ◽  
Anterior Teeth ◽  
Chewing Behaviour

Dental microwear texture analysis (DMTA) is widely used for diet inferences in extant and extinct vertebrates. Often, a reference tooth position is analysed in extant specimens, while isolated teeth are lumped together in fossil datasets. It is therefore important to test whether DMT is tooth position specific, and if so, what the causes for wear differences are. Here we present results from controlled feeding experiments with 72 guinea pigs, which either received fresh or dried natural plant diets of different phytolith content (lucerne, grass, bamboo), or pelleted diets with and without mineral abrasives (frequently encountered by herbivorous mammals in natural habitats). We test for gradients in dental microwear texture along the upper cheek tooth row. Regardless of abrasive content, pelleted diets display an increase in surface roughness along the tooth row, indicating that posterior tooth positions experience more wear compared to anterior teeth. Guinea pigs feedings on plants of low phytolith content and low abrasiveness (fresh and dry lucerne, fresh grass) show almost no DMT differences between tooth positions, while individuals feeding on more abrasive plants (dry grass, fresh and dry bamboo) show a gradient of decreasing surface roughness along the tooth row. We suggest that plant feeding involves continuous intake and comminution by grinding, resulting in posterior tooth positions mainly processing food already partly comminuted and moistened. Pelleted diets require crushing, which exerts higher loads, especially on posterior tooth positions, where bite forces are highest. These differences in chewing behaviour result in opposing wear gradients for plant versus pelleted diets.

scholarly journals Shape, size, and quantity of ingested external abrasives influence dental microwear texture formation in guinea pigs

2020 ◽  
Vol 117 (36) ◽  
pp. 22264-22273 ◽  
Author(s):  
Daniela E. Winkler ◽  
Thomas Tütken ◽  
Ellen Schulz-Kornas ◽  
Thomas M. Kaiser ◽  
Jacqueline Müller ◽  
...  
Keyword(s):  
Guinea Pigs ◽  
Volcanic Ash ◽  
Mineral Dust ◽  
Control Diet ◽  
Tooth Wear ◽  
Coarse Grained ◽  
Dental Microwear ◽  
Fine Grained ◽  
Feeding Experiments ◽  
Dental Microwear Texture Analysis

Food processing wears down teeth, thus affecting tooth functionality and evolutionary success. Other than intrinsic silica phytoliths, extrinsic mineral dust/grit adhering to plants causes tooth wear in mammalian herbivores. Dental microwear texture analysis (DMTA) is widely applied to infer diet from microscopic dental wear traces. The relationship between external abrasives and dental microwear texture (DMT) formation remains elusive. Feeding experiments with sheep have shown negligible effects of dust-laden grass and browse, suggesting that intrinsic properties of plants are more important. Here, we explore the effect of clay- to sand-sized mineral abrasives (quartz, volcanic ash, loess, kaolin) on DMT in a controlled feeding experiment with guinea pigs. By adding 1, 4, 5, or 8% mineral abrasives to a pelleted base diet, we test for the effect of particle size, shape, and amount on DMT. Wear by fine-grained quartz (>5/<50 µm), loess, and kaolin is not significantly different from the abrasive-free control diet. Fine silt-sized quartz (∼5 µm) results in higher surface anisotropy and lower roughness (polishing effect). Coarse-grained volcanic ash leads to significantly higher complexity, while fine sands (130 to 166 µm) result in significantly higher roughness. Complexity and roughness values exceed those from feeding experiments with guinea pigs who received plants with different phytolith content. Our results highlight that large (>95-µm) external silicate abrasives lead to distinct microscopic wear with higher roughness and complexity than caused by mineral abrasive-free herbivorous diets. Hence, high loads of mineral dust and grit in natural diets might be identified by DMTA, also in the fossil record.

scholarly journals FEEDING EXPERIMENTS WITH BACTERIUM PULLORUM. THE TOXICITY OF INFECTED EGGS

1916 ◽  
Vol 23 (4) ◽  
pp. 475-489 ◽  
Author(s):  
Leo F. Rettger ◽  
Thomas G. Hull ◽  
William S. Sturges
Keyword(s):  
Young Children ◽  
Guinea Pigs ◽  
Domestic Fowl ◽  
Food Poisoning ◽  
Later Life ◽  
Wide Distribution ◽  
Feeding Experiments ◽  
Large Numbers ◽  
Poultry Breeding ◽  
Viable Bacteria

The problem of eradicating ovarian infection in the domestic fowl assumes still greater importance than heretofore, in the light of data recently acquired. Not only is it of great significance to eliminate the permanent carriers of Bacterium pullorum from all flocks of fowls from the standpoint of successful poultry breeding, but also because they constitute a possible source of danger to man. Eggs which harbor Bacterium pullorum in the yolk in large numbers may produce abnormal conditions, when fed, not only in young chicks, but in adult fowls, young rabbits, guinea pigs, and kittens. The toxicity for young rabbits is most pronounced, the infection usually resulting in the death of the animals. In kittens the most prominent symptoms are those of severe food-poisoning with members of the paratyphoid group of bacteria. The possibility of infected eggs causing serious disturbances in young children and in the sick and convalescent of all ages must therefore receive serious consideration. Ovarian infection of fowls is very common throughout this country. Hence, a large proportion of the marketed eggs are infected with Bacterium pullorum. When such eggs are allowed to remain in nests under broody hens, or in warm storage places, for comparatively few hours, they contain large numbers of the organism. Soft boiling, coddling, and frying on one side only do not necessarily render the yolks free from viable bacteria; therefore, eggs which have gone through these processes may, like raw eggs, be the cause of serious disturbances in persons who are particularly susceptible to such influences, and especially to infants. That no well authenticated instances of egg-poisoning of this kind are on record does not warrant the assumption that there have been no cases. The etiology of infantile stomach and intestinal disturbances is as yet too little understood; in fact, it may be said that many of these disorders have no known cause, and almost as much may be said regarding gastro-intestinal diseases in later life. Furthermore, since the ailments caused by infected eggs would not make themselves felt presumably until several days after their ingestion, little or no suspicion would fall upon the eggs. It may be said, too, that the wide distribution of ovarian infection in the domestic fowl has come about only in the last few years, hence its possible danger to man is one of recent development.

Caries Prevalence, Severity, and Pattern in Preschool Children

2008 ◽  
Vol 9 (3) ◽  
pp. 24-31 ◽  
Author(s):  
Amjad H. Wyne
Keyword(s):  
Preschool Children ◽  
Anterior Tooth ◽  
World Health ◽  
Caries Prevalence ◽  
Posterior Teeth ◽  
Posterior Tooth ◽  
Decay Component ◽  
Anterior Teeth ◽  
Significant Difference ◽  
Health Organization

Abstract Aim To determine caries prevalence, severity, and pattern in preschool children of Riyadh, Saudi Arabia. Methods and Materials A total of 789 randomly selected preschool children, 379 (48%) male and 410 (52%) female, with mean age of 4.7 (SD 0.5) years were examined for dental caries using World Health Organization (WHO) diagnostic criteria. Results The overall caries prevalence among the sample was 74.8%. The mean decayed, missing, and filled (dmft) score was 6.1 (SD 3.9) with a decay component of 4.66, a missing component of 0.54, and a filled component of 0.92. There was no significant difference (p>.05) in caries prevalence and severity in relation to gender of the children. However, the caries prevalence and severity were significantly higher (p<.05) among children from government preschools as compared to those from private preschools. Among the posterior teeth, mandibular second molars (54.3%), and among anterior teeth, maxillary central incisors (27.9%) had the highest caries prevalence. Among the molars, caries prevalence was generally high in lower molars while among the anterior teeth, upper teeth generally had a higher caries prevalence. The majority of the children (50.3%) had both posterior and anterior tooth caries, 42.2% had posterior tooth caries only, while very few (7.5%) children had only anterior tooth caries. Conclusion Caries prevalence and severity are very high in the study population, and most children have posterior tooth caries. Clinical Significance Early measures such as fissure sealants, topical fluoride applications (as early as safely possible), and dietary fluoride supplements (where indicated) are needed to prevent caries of deciduous molars in high caries populations. Citation Wyne AH. Caries Prevalence, Severity, and Pattern in Preschool Children. J Contemp Dent Pract 2008 March; (9)3:024-031.

The Clinical Study of Detecting the Endodontic Vitality Clinical Reference Range of Anterior Teeth in Children Used By Laser Doppler Flowmetry

2020 ◽  
Author(s):  
Kuang Yang ◽  
Feifei Guo ◽  
Zhifei Zhou ◽  
Zeming Hui ◽  
Zirui Wang ◽  
...  
Keyword(s):  
Laser Doppler Flowmetry ◽  
Reference Range ◽  
Statistical Significance ◽  
Laser Doppler ◽  
School Age Children ◽  
Healthy Children ◽  
Doppler Flowmetry ◽  
Tooth Position ◽  
Anterior Teeth ◽  
The Difference

Abstract Aim: To measure the pulpal blood flow (PBF) of the upper incisors using the laser Doppler flowmetry (LDF) and to calculate the endodontic vitality clinical reference range using PBF as an indicator in the healthy children. To clarify the factors that might interfere the detection and interpretation of the results. Methods: Seven to twelve-year-old school-age children were recruited randomly. The basic characteristics of the subjects are described in terms of age and gender. The mean, standard deviation, and reference range of the subjects’ PBF values are described based on their age, sex, and tooth position. Multi-factor analysis of variance was implemented, mainly including age, gender, and tooth position. Results: 1) The clinical reference range of the anterior teeth PBF in children of different ages was preliminary defined that was approximately among the range of 7-14. 2). A statistically significant correlation between PBF and age in school-aged children (P < 0.05) was detected and no statistical significance between genders (P > 0.05) was detected. The PBF detection value of lateral incisors was higher than that of central incisors, and the difference was statistically significant (P < 0.05). Conclusion: The determination of the range of clinical reference of anterior teeth PBF in children by LDF could provide a good theoretical basis and reference basis for further promotion of its application.

scholarly journals When the going gets rough – studying the effect of surface roughness on the adhesive abilities of tree frogs

2016 ◽  
Vol 7 ◽  
pp. 2116-2131 ◽  
Author(s):  
Niall Crawford ◽  
Thomas Endlein ◽  
Jonathan T Pham ◽  
Mathis Riehle ◽  
W Jon P Barnes
Keyword(s):  
Surface Roughness ◽  
Real Contact Area ◽  
Small Scale ◽  
Tree Frog ◽  
Natural Habitats ◽  
Litoria Caerulea ◽  
Frictional Forces ◽  
Tree Frogs ◽  
Air Pockets ◽  
Effect Of Surface

Tree frogs need to adhere to surfaces of various roughnesses in their natural habitats; these include bark, leaves and rocks. Rough surfaces can alter the effectiveness of their toe pads, due to factors such as a change of real contact area and abrasion of the pad epithelium. Here, we tested the effect of surface roughness on the attachment abilities of the tree frog Litoria caerulea. This was done by testing shear and adhesive forces on artificial surfaces with controlled roughness, both on single toe pads and whole animal scales. It was shown that frogs can stick 2–3 times better on small scale roughnesses (3–6 µm asperities), producing higher adhesive and frictional forces, but relatively poorly on the larger scale roughnesses tested (58.5–562.5 µm asperities). Our experiments suggested that, on such surfaces, the pads secrete insufficient fluid to fill the space under the pad, leaving air pockets that would significantly reduce the Laplace pressure component of capillarity. Therefore, we measured how well the adhesive toe pad would conform to spherical asperities of known sizes using interference reflection microscopy. Based on experiments where the conformation of the pad to individual asperities was examined microscopically, our calculations indicate that the pad epithelium has a low elastic modulus, making it highly deformable.

scholarly journals Chemical identification of 18-hydroxycarlactonoic acid as an LjMAX1 product and conversion of 18-hydroxylcarlactonoates to canonical and non-canonical strigolactones in Lotus japonicus

2019 ◽  
Author(s):  
Narumi Mori ◽  
Aika Sado ◽  
Xiaonan Xie ◽  
Kaori Yoneyama ◽  
Kei Asami ◽  
...  
Keyword(s):  
Mycorrhizal Fungi ◽  
Plant Architecture ◽  
Lotus Japonicus ◽  
Arbuscular Mycorrhizal ◽  
Insertion Mutant ◽  
Methyl Ester Derivative ◽  
Model Legume ◽  
Plant Feeding ◽  
Feeding Experiments ◽  
Endogenous Compound

AbstractStrigolactones (SLs) are a group of plant apocarotenoids that act as rhizosphere signaling molecules for both arbuscular mycorrhizal fungi and root parasitic plants. They also regulate plant architecture as phytohormones. The model legume Lotus japonicus produces canonical 5-deoxystrigol (5DS) and non-canonical lotuslactone (LL). The biosynthesis pathways of the two SLs remain elusive. In this study, we characterized the L. japonicus MAX1 homolog, LjMAX1, found in the Lotus japonicus genome assembly build 2.5. The L. japonicus max1 LORE1 insertion mutant was deficient in 5DS and LL production. A recombinant LjMAX1 protein expressed in yeast microsomes converted carlactone (CL) to 18-hydroxycarlactonoic acid (18-HO-CLA) via carlactonoic acid (CLA). Identity of 18-HO-CLA was confirmed by comparison of the methyl ester derivative of the MAX1 product with the chemically synthesized methyl 18-hydroycarlactonoate (18-HO-MeCLA) using LC-MS/MS. (11R)-CL was detected as an endogenous compound in the root of L. japonicus.13C-labeled CL, CLA, and 18-HO-MeCLA were converted to [13C]-5DS and LL in plant feeding experiments using L. japonicus WT. These results showed that LjMAX1 is the crucial enzyme in the biosynthesis of Lotus SLs and that 18-hydroxylated carlactonoates are precursors for SL biosynthesis in L. japonicus.

scholarly journals Complete Maxillary Denture Mobility Related to Posterior Tooth Position.

1998 ◽  
Vol 42 (3) ◽  
pp. 415-423
Author(s):  
Kensuke Kakihara ◽  
Kenji Notani ◽  
Takao Kawasaki ◽  
Kentarou Mizuno ◽  
Naoki Ohta ◽  
...  
Keyword(s):  
Tooth Position ◽  
Posterior Tooth

scholarly journals Smile Design with All Ceramic Veneers

2017 ◽  
Vol 2 (1) ◽  
pp. 51-54
Author(s):  
Dileep Soni ◽  
Ashwani B Prasad
Keyword(s):  
Management Option ◽  
Adhesively Bonded ◽  
Present Case Report ◽  
Tooth Position ◽  
Anterior Teeth ◽  
All Ceramic ◽  
Natural Teeth ◽  
Tooth Preparation ◽  
Points Of View ◽  
Laminate Veneers

ABSTRACT The use of porcelain laminate veneers to solve esthetic and/or functional problems has been shown to be a valid management option, especially in the anterior esthetic zone. In cases when patients decline orthodontic treatment, adhesively bonded porcelain veneers are a reliable treatment option to modify the appearance of tooth position and form, to close diastema or cervical embrasures, or to change the tooth shade. Porcelain veneers are one of the best corrective options available considering biological, functional, mechanical, and esthetic points of view. The present case report is about discolored anterior teeth in a healthy dentition by means of sectional porcelain veneers simply cemented onto the natural teeth and with minimal tooth preparation. How to cite this article Soni D, Raisingani D, Prasad AB, Mital P, Srivastava H, Dixit A. Smile Design with All Ceramic Veneers. J Mahatma Gandhi Univ Med Sci Tech 2017;2(1):51-54.

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