scholarly journals A unique mineralization mode of hypermineralized pleromin in the tooth plate of Chimaera phantasma contributes to its microhardness

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mayumi Iijima ◽  
Mikio Ishiyama
Keyword(s):  
Dietary Habits ◽  
Tooth Enamel ◽  
The Other ◽  
Mineralized Tissue ◽  
Mineral Phase ◽  
Lower Jaw ◽  
Other Hand ◽  
Tooth Plate ◽  
Dental Hard Tissues ◽  
Hard Tissues

Abstract Tooth plates of the chimaeroids, holocephalian fishes, are unique dental hard tissues. Unlike the teeth of other animals, the tooth plates are located on the roof of the mouth and in the lower jaw. Their tooth plates consist, to a large extent, of lightly mineralized tissue (osteodentin) and hypermineralized tissue (pleromin). Notably, the mineral phase of pleromin is whitlockite, while that of other animals is apatite. Dietary habits of chimaeroids and wearing features of their tooth plates suggest an extreme hardness of pleromin, but this has never been investigated. We examined the microhardness of the tooth plate of Chimaera phantasma and found that pleromin in the biting region was extremely hard, comparable with the hardness of mature tooth enamel, whereas the hardness of immature pleromin was lower than that of bovine dentin. The hardness of osteodentin, on the other hand, was equivalent to that of bovine dentin and almost the same throughout the tooth plate. Immature pleromin was sparsely packed with oval crystals of whitlockite and, as pleromin matures, the space between crystals was filled with small intercrystalline materials. The maturing process of pleromin could partly contribute to its remarkable hardness and have some implications for designing novel biomaterials.

scholarly journals Kappa-splints application for the treatment of pathological dental hard tissues abrasion in combination with dentition defects and dentition deformations

2017 ◽  
Vol 24 (1) ◽  
pp. 201716 ◽  
Author(s):  
Svitlana Petrishin ◽  
Z Ozhohan
Keyword(s):  
Tooth Wear ◽  
Masticatory Muscles ◽  
Vertical Movements ◽  
Clinical Method ◽  
Occlusal Splints ◽  
Treatment And Prevention ◽  
Lower Jaw ◽  
Dental Hard Tissues ◽  
Hard Tissues ◽  
Hinge Axis

Research objective: to develop and implement a new clinical method of producing a set of kappa-splints for splint therapy: treatment and prevention of various forms of pathological teeth abrasion in combination with dentition defects and dentition deformations, which will enable to prevent significant disorders in the dentition.Materials and Methods: 36 patients aged 30-59 have been selected for the targeted research with a generalized form of pathological tooth wear in combination with dentition defects and dentition deformations.Results: After studying the movements of conventional hinge axis in articulate heads of TMJ with the help of condylograph «Cadiax Compact», some asynchronous, asymmetrical bias of articulate heads during the movements of the mandible were revealed in patients with pathological tooth wear in combination with dentitiondefects and dentition deformations. While examining, the patients complained about the aesthetic defects due to the abrasion of teeth and the change of their colour, the discomfort while closing, chewing and phonetic disorders. In the clinical picture of these patients, the typical symptoms of TMJ dysfunction can be singled out, such as pain and crunch in joints, fatigue of chewing muscles and pain in the muscles, the displacement of the mandible to the side during vertical movements, a feeling of fullness in the ears, headaches and bruxism. Dentition deformations were presented as a violation of the occlusal curve. The results indicate on the presence of functional TMJ disorders and masticatory muscles dysfunction in pathological teeth abrasion in combination with dentition defects.So, in most cases, temporary prosthesis structures and occlusal splints can be applied to normalize occlusive correlations at the dysfunction of TMJ and masticatory muscles. Gradual lifting of occlusion has been done due to a set of kappa-splints in terms of 14 days, 1 month and 3 months from 1.0 to 5.0 mm to the full restoration of occlusal height, depending on the severity of pathological teeth abrasion. It is the gradual application of a kappa-splints’ set which allows prevention of further tooth wear; it doesn’t influence the periodontium of teeth; it’s aesthetic and does not violate the pronunciation of sounds. The material, which a kappa-splints set is made of, provides better fixation and bite separation with optimal thickness throughout the dentition, which allows the lower jaw to take a position that helps to restore the functional balance of the entire dentition.Conclusions:1. According to the results of the research it has been established that the orthopedic treatment with the help of occlusive splints at the preparatory stage for the patients with occlusive disorders at pathological dental hard tissues abrasion in combination with dentition defects, periodontium tissue disease and dentition deformations are urgent for the normalization of occlusive correlations of the jaws.2. After studying the movements of conventional hinge axis in articulate heads of TMJ with the help of condylograph «Cadiax Compact» and eliminating the symptoms of stress in masticatory muscles of the patients with occlusive disorders at pathological dental hard tissues abrasion, it is the gradual application of a kappa-splints set, made of hard transparent plates of Ercodent Ercodur material (Germany) with a thickness of 1.0 to 5.0 mm, which allows prevention of further tooth wear, normalization of occlusive correlations of the jaws, separating a bite with optimum thickness throughout the dentition, thus the lower jaw takes a position at which the state of functional equilibrium of the entire dentition is restored.

scholarly journals Caries Resistance - Criterion of Dental Status of Children and Adolescents

2021 ◽  
Vol 6 (2) ◽  
pp. 13-19
Author(s):  
O. V. Klitynska ◽  
◽  
T. I. Zorivchak ◽  
V. V. Shetelya
Keyword(s):  
Dental Caries ◽  
Tooth Enamel ◽  
Chemical Elements ◽  
Pediatric Dentistry ◽  
The Body ◽  
Permanent Teeth ◽  
Common Disease ◽  
Dental Tissues ◽  
Dental Hard Tissues ◽  
Hard Tissues

Prevention of dental caries in children is one of the current problems of modern pediatric dentistry, which is due to the high prevalence and intensity of this disease. Analysis of the results of epidemiological studies conducted among children of different ages in the regions of Ukraine shows a significant increase in caries growth in recent years, both temporary and permanent teeth, which leads to in-depth study of the hardness of dental tissues to cariogenic factors in connection with the need in the constant improvement of methods of treatment and prevention of this pathology. The purpose of the study was to analyze the value of enamel caries resistance as a detector of resistance of dental hard tissues to carious process and its complications. The subject of the research is the work of domestic and foreign researchers on this topic. In the course of the research the bibliosemantic method and structural-logical analysis were used. Today, dental caries is the most common disease in different age groups, which is confirmed by the prevalence – 90-100% and a sharp trend of increasing its intensity. Given the high rates of this pathology, it should be remembered that its untimely treatment leads to the following complications: pulpitis, periodontitis, tooth extraction. An important concept that indicates the possibility of caries is caries resistance, which indicates the level of resistance of the enamel to caries and has an informative diagnostic value for the dentist. According to modern ideas, in the pathogenesis of dental caries the leading role is played by caries-resistant enamel. Its mineral base is formed by isomorphic crystals of apatite, which contain various chemical elements, and their amount in the body is closely related to the amount in the environment. It is established that more than 40 chemical elements take part in the process of tooth mineralization, the most important of which belongs to calcium, phosphorus, fluoride. Insufficient amount or excess of certain micronutrients in the environment, especially in soils and drinking water, can change their content in the body and, consequently, in the hard tissues of the teeth, affecting their resistance to caries. It is well known that the influence of a number of adverse environmental factors leads to a decrease in the resistance of the body as a whole and, as a consequence, to a decrease in the caries resistance of the enamel of the hard tissues of the teeth. Sensitivity to the effects of adverse factors increases significantly in the prepubertal period, a time not only of intensive growth of the child and the formation of his personality, but also a period of mineralization of more than half of permanent teeth. Therefore, exactly at this time dentists should pay special attention to the prevention of caries of permanent teeth in children by improving the conditions of secondary mineralization of tooth enamel, thereby increasing their level of caries resistance

scholarly journals Evaluasi Pola Makan sebagai Upaya Pengurangan Kambuh pada Penderita Gastritis Usia Remaja

2019 ◽  
Author(s):  
Helvy Aldelina
Keyword(s):  
Direct Effect ◽  
Dietary Habits ◽  
Sampling Technique ◽  
The Other ◽  
Mucous Layer ◽  
Purposive Sampling ◽  
Other Hand

Gastritis is an inflamation that occur in the stomach mucous layer. It can happens because improper dietary habits that include frequency of meals, type and amount of food. The aim of this study is to evaluate dietary habits as an attempt to reduce relapse frequency in gastritis sufferer of adolescent. The study was descriptive using purposive sampling technique. Instrument used in this research was questionnaire. The research was held on June 2019 with 12 respondents of karang taruna Sinar remaja organization. This study found that more than a half of respondent have Improper dietary habits especially the type of food. They consumed irritative food that cause increasing the frequency of relapse. On the other hand, frequency of meals and amount of food don’t have direct effect on frequency relapse of gastritis

scholarly journals Correlation between five parameters for the assessment of sagittal skeletal intermaxillary relationship

2007 ◽  
Vol 54 (4) ◽  
pp. 231-239 ◽  
Author(s):  
Tamara Boskovic-Brkanovic ◽  
Zorana Nikolic
Keyword(s):  
Clinical Practice ◽  
Health Center ◽  
Basic Characteristic ◽  
The Other ◽  
X Rays ◽  
Skeletal Class ◽  
Lower Jaw ◽  
Other Hand ◽  
Precise Diagnosis ◽  
Complex Cases

Introduction: Sagittal relationship between the upper and lower jaw represent the basic characteristic of human profile. It is one of the most important criteria assessed during the diagnosis of orthodontic anomalies. For this purpose, numerous parameters have been proposed, but ANB angle, Wits assessment, Down?s angle of facial skeletal convexity-NAPg and Schwartz?s indicators of sagittal intermaxillary relationship, i.e. AB/SpP and MM angles are the most commonly used in clinical practice. However, there is a suggestion by other authors, in more complex cases, several parameters instead of one should be used for a more precise diagnosis of skeletal class. Aim: The aim of this paper was to examine the correlation between ANB angle, Wits assessment, NAPg angle, AB/SpP angle and MM angle. Materials and Methods: The study was conducted on profile cephalograms of 137 children, age 7-12, the patients of Dept. of Orthodontics in the Health Center Kotor. The aforementioned sagittal skeletal parameters were determined on tele-X-rays. The study comprised all three classes of malocclusion. Results: The analysis of obtained results revealed a statistically significant and high correlation between ANB angle Wits values and NAPg angle. Moreover, the correlation between ANB and NAPg angles was statistically most prominent (r=0.776). On the other hand, no statistically significant correlation was found between Schwartz parameters (AB/SpP angle and MM angle) and the previously mentioned ones. Conclusion: Based on the obtained results, it can be concluded that ANB angle, Wits values and NAPg angle can be used one instead of another for the assessment of sagittal skeletal intermaxillary relationship, whilst Schwartz parameters should be used in combination with other indicators of this relationship for a more realistic diagnosis.

scholarly journals COMPREHENSIVE STUDY OF ORAL HYGIENE STATUS IN 40-50 YEAR-OLD WOMEN RANGES USING DRUG PRODUCT TO INCREASE RESISTANCE OF DENTAL HARD TISSUES.

2019 ◽  
Vol 9 (3) ◽  
pp. 343-346
Author(s):  
Barylo O.S., Agafonov K.V., Kirichek O.V., Furman R.L.*
Keyword(s):  
Oral Hygiene ◽  
Tooth Enamel ◽  
Drug Product ◽  
Physiological Solution ◽  
Control Group ◽  
Surface Layers ◽  
Dental Hard Tissues ◽  
Hard Tissues ◽  
Index Estimation

Resistance of tooth enamel to aggressive effect of metabolic by-products of oral cavity microorganisms is provided by fluoroapatites of enamel surface layers. The patients were divided into two groups: control group (30 females) and experimental (observa-tion) group (30 females). In control group, the traditional method of caries prevention was used, which included professional teeth cleaning, mouthwash with physiological solution (0.9%) of sodium chloride after meals, hygienic teeth brushing by a standard method twice a day. Females of experimental group underwent professional teeth cleaning, treatment of teeth with the drug product containing sodium fluoride to in-crease the resistance of hard tissues of teeth, silver nitrate and decamethoxin, rinsing with standardized decamethoxin solution. Various indices are used in modern den-tistry to evaluate oral hygiene status. Index estimation provides quantitative charac-teristics of static status of oral hygiene. Their values enable to suggest the course of inflammatory-destructive or dystrophic process and its severity, to evaluate treatment efficacy and quality of regular check-up of a particular patient or dispensary cases. The study demonstrated significant positive clinical efficacy of the drug product used to increase resistance of dental hard tissues. In particular, patients using the pharma-ceutical preparation to improve the resistance of dental hard tissues, had significantly lower values of Fedorov-Volodkina’s Index, Greene-Vermillion Index (Oral Hygiene Index- Simplified), Patient Hygiene Performance (PHP) Index as compared to the control group.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Life Beyond 1MeV

1980 ◽  
Vol 38 ◽  
pp. 30-33
Author(s):  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
Past Experience ◽  
The Other ◽  
Good Case ◽  
Other Hand ◽  
The U.S

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.

Can the Academic Self-Concept be Positive and Realistic?

2005 ◽  
Vol 19 (3) ◽  
pp. 129-132 ◽  
Author(s):  
Reimer Kornmann
Keyword(s):  
Academic Performance ◽  
Opposite Effect ◽  
Self Esteem ◽  
Point Of View ◽  
The Other ◽  
Self Concept ◽  
High Ability ◽  
Self Image ◽  
Other Hand

Summary: My comment is basically restricted to the situation in which less-able students find themselves and refers only to literature in German. From this point of view I am basically able to confirm Marsh's results. It must, however, be said that with less-able pupils the opposite effect can be found: Levels of self-esteem in these pupils are raised, at least temporarily, by separate instruction, academic performance however drops; combined instruction, on the other hand, leads to improved academic performance, while levels of self-esteem drop. Apparently, the positive self-image of less-able pupils who receive separate instruction does not bring about the potential enhancement of academic performance one might expect from high-ability pupils receiving separate instruction. To resolve the dilemma, it is proposed that individual progress in learning be accentuated, and that comparisons with others be dispensed with. This fosters a self-image that can in equal measure be realistic and optimistic.

Stories and the Self

2020 ◽  
Vol 32 (2) ◽  
pp. 47-58 ◽  
Author(s):  
Stefan Krause ◽  
Markus Appel
Keyword(s):  
Meta Analysis ◽  
The Self ◽  
The Other ◽  
Lower Degree ◽  
Contrast Effects ◽  
Self Perception ◽  
Self Perceptions ◽  
Other Hand ◽  
The One ◽  
Implicit And Explicit

Abstract. Two experiments examined the influence of stories on recipients’ self-perceptions. Extending prior theory and research, our focus was on assimilation effects (i.e., changes in self-perception in line with a protagonist’s traits) as well as on contrast effects (i.e., changes in self-perception in contrast to a protagonist’s traits). In Experiment 1 ( N = 113), implicit and explicit conscientiousness were assessed after participants read a story about either a diligent or a negligent student. Moderation analyses showed that highly transported participants and participants with lower counterarguing scores assimilate the depicted traits of a story protagonist, as indicated by explicit, self-reported conscientiousness ratings. Participants, who were more critical toward a story (i.e., higher counterarguing) and with a lower degree of transportation, showed contrast effects. In Experiment 2 ( N = 103), we manipulated transportation and counterarguing, but we could not identify an effect on participants’ self-ascribed level of conscientiousness. A mini meta-analysis across both experiments revealed significant positive overall associations between transportation and counterarguing on the one hand and story-consistent self-reported conscientiousness on the other hand.

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