scholarly journals Phenotypic and Genotypic Selection of Microbiota Surviving under Dental Restorations

2005 ◽  
Vol 71 (5) ◽  
pp. 2467-2472 ◽  
Author(s):  
J. S. Paddick ◽  
S. R. Brailsford ◽  
E. A. M. Kidd ◽  
D. Beighton
Keyword(s):  
Serum Proteins ◽  
Genotypic Diversity ◽  
Salivary Secretion ◽  
Dentinal Tubules ◽  
Actinomyces Naeslundii ◽  
Dental Restorations ◽  
Final Sample ◽  
Carious Lesions ◽  
Carious Dentine ◽  
Selection Of

ABSTRACT The effects of sealing infected carious dentine below dental restorations on the phenotypic and genotypic diversity of the surviving microbiota was investigated. It was hypothesized that the microbiota would be subject to nutrient limitation or nutrient simplification, as it would no longer have access to dietary components or salivary secretion for growth. The available nutrients would be limited primarily to serum proteins passing from the pulp through the patent dentinal tubules to the infected dentine. Ten lesions were treated, and infected dentine was sealed below dental restorations for approximately 5 months. Duplicate standardized samples of infected dentine were taken at baseline and after the removal of the restorations. The baseline microbiota were composed primarily of Lactobacillus spp., Streptococcus mutans, Streptococcus parasanguinis, Actinomyces israelii, and Actinomyces gerencseriae. None of these taxa were isolated among the microbiota of the dentine samples taken after 5 months, which consisted of only Actinomyces naeslundii, Streptococcus oralis, Streptococcus intermedius, and Streptococcus mitis. The microbiota of the final sample exhibited a significantly (P < 0.001) increased ability to produce glycosidic enzymes (sialidase, β-N-acetylglucosaminidase, and β-galactosidase), which liberate sugars from glycoproteins. The genotypic diversity of S. oralis and A. naeslundii was significantly (P = 0.002 and P = 0.001, respectively) reduced in the final samples. There was significantly (P < 0.001) greater genotypic diversity within these taxa between the pairs of dentine samples taken at baseline than was found in the 5-month samples, indicating that the dentine was more homogenous than it was at baseline. We propose that during the interval between placement of the restorations and their removal, the available nutrient, primarily serum proteins, or the relative simplicity and homogeneity of the nutrient supply significantly affected the surviving microbiota. The surviving microbiota was less complex, based on compositional, phenotypic, and genotypic analyses, than that isolated from carious lesions which were also exposed to salivary secretions and pH perturbations.

Study of a Morphometric Model for Histological Evaluation of the Collagen in Dentin Carious Lesions

2008 ◽  
Vol 33 (2) ◽  
pp. 123-126 ◽  
Author(s):  
Sérgio Luiz Pinheiro ◽  
Amanda Dias Frasson ◽  
Iris Nogueira Bincelli ◽  
Pedro Paulo Barros ◽  
Gustavo Henrique Silva
Keyword(s):  
Histological Evaluation ◽  
Collagen Structure ◽  
Test Results ◽  
Double Blind ◽  
Dentinal Tubules ◽  
Carious Lesions ◽  
Reproducible Method ◽  
The Mean ◽  
Student Test ◽  
Sirius Red

Objective: The guidelines of minimum intervention recommend the maintenance of the affected dentin; in the other hand, there are few methods able to analyze the presence of intratubular collagen. The objective of this study was to assess the collagen structure in carious dentin. Study design: Ten collected samples of infected and affected dentin were stained with hematoxilin-eosin (HE) and Sirius Red (SR). The areas intensively stained with SR were delimited and the percentage of these areas was measured by double-blind calibrated examiners. The mean results were subjected to the t-student test. The amount of dentinal tubules and their area (pixels) were evaluated by HE, and subjected to the Mann Whitney test. Results: The mean of dentinal tubules in the infected dentin was 213.22 and in the affected dentin it was 120.85 (p&lt;0.05). The mean area of dentinal tubules in the infected dentin was 1175.16 and in the affected dentin was 1420.70(p&gt;0.05). The percentage of intratubular organized collagen in the infected dentin was 12.71% and in the affected dentin it was 32.37% (p&lt;0.05). Conclusions: The histological evaluation of the collagen is a reproducible method to perform the morphometry in carious dentin and the affected dentin presents structured collagen areas where reorganization is possible.

scholarly journals Genetic analysis of sweet corn lines based on SH2 endosperm structure gene

2020 ◽  
Vol 11 (3) ◽  
pp. 80-87
Author(s):  
O. Yu. Kulish ◽  
◽  
M. F. Parii ◽  
Keyword(s):  
Sweet Corn ◽  
Starch Synthesis ◽  
Morphological Characteristics ◽  
Genotypic Diversity ◽  
Recessive Mutation ◽  
Biological Traits ◽  
Seed Productivity ◽  
Linear Material ◽  
Endosperm Structure ◽  
Selection Of

One of the three genes of the endosperm structure is used in the selection of sweet corn; its recessive mutation sh2 activates the accumulation of sucrose in the structural complex of sugars and represses the starch synthesis. Hybrids of "super-sweet" corn have improved grain taste and slower conversion of sugars into starch. Therefore, it is important to use different genetic sources of breeding traits in the creation of a new linear material that meets the requirements of modern heterosis selection of sweet corn. The aim of the work was to study the lines of sweet corn and to identify among them new sources of selectively valuable economic features. A complex assessment of morphological characteristics and productivity of sweet corn lines was carried out. According to the results of study the main morpho-biological traits of sweet corn lines with the mutant sh2 gene, the sources of individual selection valuable peculiarities were identified. Lines SH-234 and SH-936 were marked as donors of plant growth. Lines SH-621, SH-234 and SH-936 were the best in terms of seed productivity of cobs. According to the growing season, all lines are divided into early (4 lines) and medium ripe (6 lines). The lines SH-234, SH-113 (number of grain rows) and SH-621 (number of seeds in a row) were the best in terms of productivity, and lines SH-318 and SH-936 – in terms of the cob length (14.45 cm and 13.26 cm, respectively). Only one line SH-477 had strongly wrinkled seeds. Thus, the studied sweet corn lines were characterized by high genotypic diversity; the SH-936 and SH-621 lines were the best in terms of the trait complex.

scholarly journals Screening economically important features of spring common wheat varieties of CIMMYT breeding in the central Russia

2021 ◽  
Vol 845 (1) ◽  
pp. 012065
Author(s):  
V S Rubets ◽  
V V Pylnev ◽  
I N Voronchihina ◽  
Yu N Kotenko ◽  
D D Taranova
Keyword(s):  
Common Wheat ◽  
Abiotic Stresses ◽  
Grain Quality ◽  
Wheat Variety ◽  
Genotypic Diversity ◽  
Biotic And Abiotic Stresses ◽  
Wheat Varieties ◽  
Central Russia ◽  
Selection Of ◽  
Spring Common Wheat

Abstract Creating of populations with wide genotypic diversity is the basis of successful selection of promising lines. This can be achieved by involving breeding material from various ecological and geographical origins, as well as interspecific hybrids, in crossing. 14 spring common wheat (Triticum aestivum L.) varieties of CIMMYT breeding (Mexico) were researched to identify the genetic sources of economically important features. A number of these varieties proved to be the sources of adaptability to biotic and abiotic stresses and high grain quality. The yield properties of the Mexican varieties in the central Russia were at or below the standard – the ‘Zlata ’ wheat variety.

scholarly journals TECHNIQUES FOR FIXED DENTAL RESTORATIONS REMOVAL - CLASSIFICATION, DECISION ON THE CORRECT APPROACH, ADVANTAGES AND DISADVANTAGES

2021 ◽  
Vol 27 (1) ◽  
pp. 3510-3517
Author(s):  
Radostina Vasileva ◽  
Keyword(s):  
Clinical Situation ◽  
Complete Classification ◽  
Literature Study ◽  
Scientific Databases ◽  
Advantages And Disadvantages ◽  
Dental Restorations ◽  
Ideal System ◽  
Full Classification ◽  
Selection Of ◽  
The Ideal

Introduction: Fixed dental restorations possess a predefined period of use. Most often they are removed by means of sectioning which renders them unusable. Reasons exist when practitioners shall preserve the restoration, applying conservative approaches for removing. In the literature, apart from the classic destructive technique with sectioning, conservative, semi-conservative and combined techniques for removal are described. The aim of this article is to present a complete classification and description of different approaches to remove permanently and temporarily fixed prosthetic constructions. Materials and methods: A literature study was conducted athe beginning of 2019. Information was gathered using dental textbooks on the topic specified and online scientific databases such as PubMed, ResearchGate, etc. Conclusion Through this article, a conclusion was drawn that a full classification or description of removal techniques for fixed dentures has not been done in the Bulgarian literature so far. It is reported that information for patients about advantages, disadvantages and dangers of removing a permanently cemented restoration is of great importance. Except for the destructive ones, all methods described here may be used when removing temporarily fixated constructions. The selection of the ideal system or a combination depends on the clinical situation. Safest and most atraumatic for underlying structures when removing permanently cemented restorations is the destructive approach. Practitioners must be precisely familiar with the techniques so as to be able to preserve the construction, to avoid any danger connected with the clinical case. According to data gathered, no approach is universally applicable when removing fixed prosthetic restorations.

scholarly journals TRENDS IN SPORTS VOLUNTEERING RESEARCH: A MANAGEMENT ASPECT

2021 ◽  
Vol 7 (3) ◽  
pp. 30-36
Author(s):  
Daria F. TELEPAEVA ◽  
Maria V. PEVNAYA
Keyword(s):  
National Level ◽  
Research Direction ◽  
Scientific Review ◽  
Sports Events ◽  
Final Sample ◽  
Psychology And Economics ◽  
Mental Map ◽  
Number Of Publications ◽  
Time Frames ◽  
Selection Of

Sports volunteering as a social phenomenon attracts the attention of the world’s leading researchers in the field of sociology, psychology, and economics. Despite the large number of publications, research interest in the problems of sports volunteers is manifested periodically and, as a rule, precedes any specific sports event of an international or national level. The holding of the largest international competitions on the territory of Russia and the state interest in volunteering will determine the need for national and comparative research in the field of sports volunteering and the management of this type of activity. The aim of the work is to determine the place of sports volunteering in modern research on the basis of bibliometric analysis of publication data. The empirical research was carried out on the basis of the Scopus database in three stages: selection of documents by keywords, introduction of time frames (2005-2020) and selection of publications corresponding to the types of “article” and “scientific review”. The final sample consisted of 329 documents, which were analyzed in detail in the VOSviewer program (version 1.6.15). The authors identify the leaders of this research direction among specific organizations and countries. We analyzed the most cited publications on the topic of sports volunteering in the context of management. The authors identified thematic areas and their chronology in research, building a mental map of the most common terms. The results obtained make it possible to determine the degree of study of the phenomenon under consideration, to identify problem areas and promising directions in the study of sports volunteering. The problematic field of sports volunteering research is analyzed in the article from the managerial aspect. This formulation of the problem makes it possible to evaluate the scientific discourse of sports volunteering management at different levels: from interaction in a separate organization to the analysis of the practices of international and national management of the organization of sports events.

scholarly journals Evaluation Of The Effectiveness Of The Use Of Optical Systems In The Restoration Of Defects In The Hard Tissues Of The Tooth

2021 ◽  
Vol 03 (05) ◽  
pp. 65-67
Author(s):  
Xolboyeva Nasiba Asrorovna ◽  
◽  
Davronov Sodiqjon Valojon O’g’li ◽  
Turaeva Kamila Furkat Kizi ◽  
◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Optical Systems ◽  
Naked Eye ◽  
Dental Restorations ◽  
Carious Lesions ◽  
Hard Tissues ◽  
Aesthetic Dentistry

"Perfection is achieved not when there is nothing to add, but when there is nothing to remove" Antoine de Saint-Exupery Presents the results of a study of the performance of aesthetic and artistic restorations and the study of these dental restorations after a certain time with the naked eye and binoculars of two types, while the use of a SLR camera was a prerequisite. Comparative analysis has shown that the use of optical systems during dental manipulations significantly improves the diagnosis of carious and non-carious lesions, facilitates work and reduces the risk of various complications. Clinical photographs are an important component of aesthetic dentistry.

scholarly journals Pronounced Effect of Antibacterial Bioactive Dental Composite on Microcosm Biofilms Derived From Patients With Root Carious Lesions

2020 ◽  
Vol 7 ◽  
Author(s):  
Abdulrahman A. Balhaddad ◽  
Maria S. Ibrahim ◽  
Isadora M. Garcia ◽  
Fabrício M. Collares ◽  
Michael D. Weir ◽  
...  
Keyword(s):  
Dental Plaque ◽  
Lactic Acid Production ◽  
Resin Composites ◽  
Dental Resin ◽  
Biofilm Growth ◽  
Restorative Treatment ◽  
Dental Restorations ◽  
Dental Resin Composites ◽  
Carious Lesions ◽  
Active Root

Resin composites are the material of choice for dental restorative treatment in oral health care. However, the inherent composition of this class of material commonly results in microbial adherence and colonization, which carries the potential risk of recurrent carious lesions around dental restorations. The high risk of resin composites failure complicates the treatment of root caries, defined as the onset of tooth decay over the prone root surface of a tooth. The restorative treatment of root caries among high caries risk individuals, especially for senior patients, is a challenging, painful, and costly. The dysbiotic microbiota colonizes the composite’s surfaces and forms polymicrobial biofilms that are difficult to be dislodged by regular tooth brushing. This study assesses the antibiofilm performance of a surface contact killing antibacterial dental resin composites on the growth of microcosm biofilms using dental plaque sampled from patients with active root carious lesions as an inoculum. The designed formulations contain dimethylaminohexadecyl methacrylate (DMAHDM), a tailored quaternary ammonium monomer with an alkyl chain length of 16, at 3–5 wt.% in a base resin with and without 20 wt.% nanoparticles of amorphous calcium phosphate (NACP). Biofilms were grown on the tested resin composites using a 48 h plaque-derived microcosm biofilm model. Dental plaque collected from active root carious lesions was used as an inoculum to emulate the microbiota present in those lesions. The biofilm growth was assessed via the colony-forming unit (CFU) counts in four culture media, metabolic behavior, lactic acid production, and confocal microscopy. The percentage of reacted double bonds of the formulations was also investigated. The dental resin composites formulated with 3–5 wt.% DMAHDM and 20 wt.% NACP were effective at eradicating surface-attached biofilms from the total microbial load and each relevant cariogenic group: total streptococci, mutans streptococci, and lactobacilli. The metabolic activities and lactic acid production of the plaque-derived microcosm biofilms were reduced by 80–95%, respectively. Fewer viable microorganisms were observed over resin composites containing DMAHDM and NACP. Besides, all the experimental formulations demonstrated an acceptable degree of conversion values. This new strategy fits with ongoing dental caries preventive and minimally invasive approaches by preventing biofilm growth over-restored carious root lesions and improving the lifespan of dental restorations.

scholarly journals Effect of the Environment on Genotypic Diversity of Actinomyces naeslundii and Streptococcus oralis in the Oral Biofilm

2003 ◽  
Vol 69 (11) ◽  
pp. 6475-6480 ◽  
Author(s):  
James S. Paddick ◽  
Susan R. Brailsford ◽  
Edwina A. M. Kidd ◽  
Steven C. Gilbert ◽  
Douglas T. Clark ◽  
...  
Keyword(s):  
Genotypic Diversity ◽  
Proportional Representation ◽  
Mutans Streptococci ◽  
Acidic Ph ◽  
Oral Biofilm ◽  
Ph Values ◽  
Actinomyces Naeslundii ◽  
Streptococcus Oralis ◽  
Repetitive Extragenic Palindromic Pcr ◽  
Repetitive Extragenic Palindromic

ABSTRACT The genotypic diversity of Actinomyces naeslundii genospecies 2 (424 isolates) and Streptococcus oralis (446 isolates) strains isolated from two sound approximal sites in all subjects who were either caries active (seven subjects) or caries free (seven subjects) was investigated by using the repetitive extragenic palindromic PCR. The plaque from the caries-active subjects harbored significantly greater proportions of mutans streptococci and lactobacilli and a smaller proportion of A. naeslundii organisms than the plaque sampled from the caries-free subjects. These data confirmed that the sites of the two groups of subjects were subjected to different environmental stresses, probably determined by the prevailing or fluctuating acidic pH values. We tested the hypothesis that the microfloras of the sites subjected to greater stresses (the plaque samples from the caries-active subjects) would exhibit reduced genotypic diversity since the sites would be less favorable. We found that the diversity of A. naeslundii strains did not change (χ2 = 0.68; P = 0.41) although the proportional representation of A. naeslundii was significantly reduced (P < 0.05). Conversely, the diversity of the S. oralis strains increased (χ2 = 11.71; P = 0.0006) and the proportional representation of S. oralis did not change. We propose that under these environmental conditions the diversity and number of niches within the oral biofilm that could be exploited by S. oralis increased, resulting in the increased genotypic diversity of this species. Apparently, A. naeslundii was not able to exploit the new niches since the prevailing conditions within the niches may have been deleterious and not supportive of its proliferation. These results suggest that environmental stress may modify a biofilm such that the diversity of the niches is increased and that these niches may be successfully exploited by some, but not necessarily all, members of the microbial community.

scholarly journals Microsatellite markers reveal geographic population differentiation in Trichophyton rubrum

2007 ◽  
Vol 56 (8) ◽  
pp. 1058-1065 ◽  
Author(s):  
Yvonne Gräser ◽  
Janine Fröhlich ◽  
Wolfgang Presber ◽  
Sybren de Hoog
Keyword(s):  
Microsatellite Markers ◽  
Trichophyton Rubrum ◽  
Genotypic Diversity ◽  
Geographic Population ◽  
Multilocus Genotypes ◽  
Worldwide Distribution ◽  
Typing Methods ◽  
Multiple Strains ◽  
Two Populations ◽  
Selection Of

A worldwide selection of more than 200 isolates of the anthropophilic dermatophyte Trichophyton rubrum were analysed using seven microsatellite markers. Fifty-five multilocus genotypes were recognized, allowing a subdivision of the species into two populations. Both populations reproduced strictly clonally, showed a different predilection on the human host (scalp vs foot) and displayed geographic differentiation. Genotypes of one population originated predominantly from Africa, whilst the second population showed a worldwide distribution excluding the African continent. Genotypic diversity was highest in the African population, despite the lower number of strains analysed, suggesting that T. rubrum is likely to have evolved in Africa. No diagnostic correlation was observed between multilocus genotypes and any of the phenotypical characteristics of the strains. The involvement of multiple strains in a single patient detected by workers using other typing methods was not supported by these microsatellite markers. Four of the developed microsatellite markers may be applied for diagnostic purposes.

Sign in / Sign up

Export Citation Format

Share Document