scholarly journals Smear layer on dentin in restorative dentistry

2004 ◽  
Vol 51 (4) ◽  
pp. 169-176 ◽  
Author(s):  
Slavoljub Zivkovic ◽  
Mila Kolar ◽  
Larisa Blazic ◽  
Mirjana Vucetic ◽  
Goran Tosic
Keyword(s):  
Rapid Evolution ◽  
Adhesive System ◽  
Smear Layer ◽  
Restorative Material ◽  
Structural Elements ◽  
Restorative Dentistry ◽  
Dentin Bonding ◽  
Adhesive Dentistry ◽  
Positive Results

Adhesion to enamel has become a routine technique in restorative dentistry. Adhesion to dentin, however, is still under investigation. Except structural elements of the dentin, smear layer has been one of the reasons that the interaction between the adhesive system and this tissue is difficult. The smear layer tissue created by cutting a tooth. It varies in thickness, roughness, density and degree of attachment andoccludes tubules and reduces the dental permeabilita. Dentin adhesivesystems can react with intertubular and peritubular dentin only when this smear layer is removed or when the adhesive system is capable of diffusion through layer of debris. As part of restorative procedures required by adhesive dentistry, the smear layer must be removed, modified or impregnated by the resin to allow for bonding between the tooth and the restorative material. For remove and dissolve of smear layer acid conditioners on total etch and self-etching primers were used. Self-etching primer systems are undergoing rapid evolution; their results are not yet sufficiently predictable overall, but some systems have achieved positive results in both enamel and dentin bonding. Further studies are necessary to confirm the long-term efficiency of these self-etching primers.

Adhesion to Enamel and Dentin: A Review

2021 ◽  
Vol 1 (4) ◽  
pp. 368-376
Author(s):  
S Malhotra ◽  
R Kaur ◽  
AK Jossan ◽  
KK Bhullar ◽  
A Handa
Keyword(s):  
Adhesive System ◽  
Composite Resins ◽  
Use Of Self ◽  
Bond Quality ◽  
Bonding Agents ◽  
Posterior Teeth ◽  
Progressive Loss ◽  
Adhesive Dentistry ◽  
The World

Bonding agents play a crucial role in the effective sealing and retention of resin-based composite restorations, which have been increasingly placed and replaced by dentists in many countries around the world. In fact, direct adhesive restoration with composite resins has become the procedure of choice for the treatment of anterior and posterior teeth. However, long-term durability of those restorations may be compromised due to progressive loss of the integrity of adhesive interfaces. This means that no adhesive strategy is free from technique sensitivity. The specificity and proportion of different constitutive molecules, the interaction between them and substrates can differ greatly from one class of adhesive system to another, which can affect bond quality. Protocol simplification has been an inevitable trend that has boosted the use of self-etching and universal systems in adhesive dentistry.

Dental Materials

2019 ◽  
Author(s):  
Nicholas Longridge ◽  
Pete Clarke ◽  
Raheel Aftab ◽  
Tariq Ali
Keyword(s):  
Pure Sciences ◽  
Material Selection ◽  
Dental Materials ◽  
Restorative Dentistry ◽  
Hardening Material ◽  
Material Resources ◽  
Adhesive Dentistry ◽  
Concrete Production ◽  
Material Sciences

Dental material science can be a daunting subject for most dentists, given its origins in the pure sciences of physics and chemistry. Combining this with human biology, and trying to see through the fog of material manu­facturers’ commercial claims, can make it seem like a truly mystifying subject. It is important that any student of material sciences maintains a critical eye and an evidence- based approach when it comes to material selection and use. Today we are lucky enough to work with the most advanced dental materials we have ever had. But simply having such materials at your dis­posal does not ensure success. Clinical procedural techniques are often the prime focus in restorative dentistry; however, to achieve optimal aesthetics, function, and longevity from restorations, a clear under­standing of material sciences is required. Ancient Roman engineers clearly understood this concept when con­structing Rome. They had to work within the limitations imposed by the materials they had at their disposal. However, the longevity and solidity of the impressive infrastructure we see today can be attributed to their expertise in exploiting the unique properties of the material resources they had available. The Romans perfected concrete production (based on volcanic ash and lime reacting with seawater to form tobermorite crystals) to yield a water- hardening material, so durable and resistant to cracks that modern- day concrete (based on Portland cement) is still considered weaker. It can be argued whether operator skill or advancements in dental ma­terials have resulted in improvements in restorative dentistry. However, few would disagree that it is the combination of good operator skill and appropriate use of dental materials that is the key for successful long-term dentistry. Key topics include: ● Adhesive dentistry concepts ● Understanding material physical properties ● Elemental make- up of materials ● Manufacturing processing of materials ● Biocompatibility ● Appreciation of setting reactions and working time ● Appreciation of material aesthetic and optical properties.

Glass-ionomer Cements in Restorative Dentistry: A Critical Appraisal

2016 ◽  
Vol 17 (4) ◽  
pp. 331-336 ◽  
Author(s):  
Mohammed Almuhaiza
Keyword(s):  
Critical Appraisal ◽  
Fluoride Release ◽  
Restorative Material ◽  
Glass Ionomer Cements ◽  
Glass Ionomer ◽  
Metallic Ions ◽  
Restorative Dentistry ◽  
Tooth Structure ◽  
Wide Range

ABSTRACT Glass-ionomer cements (GICs) are mainstream restorative materials that are bioactive and have a wide range of uses, such as lining, bonding, sealing, luting or restoring a tooth. Although the major characteristics of GICs for the wider applications in dentistry are adhesion to tooth structure, fluoride releasing capacity and tooth-colored restorations, the sensitivity to moisture, inherent opacity, long-term wear and strength are not as adequate as desired. They have undergone remarkable changes in their composition, such as the addition of metallic ions or resin components to their composition, which contributed to improve their physical properties and diversified their use as a restorative material of great clinical applicability. The lightcured polymer reinforced materials appear to have substantial benefits, while retaining the advantages of fluoride release and adhesion. Further research should be directed towards improving the properties, such as strength and esthetics without altering its inherent qualities, such as adhesion and fluoride releasing capabilities. How to cite this article Almuhaiza M. Glass-ionomer Cements in Restorative Dentistry: A Critical Appraisal. J Contemp Dent Pract 2016;17(4):331-336.

The impact of Vaccination worldwide on SARS-CoV-2 infection: A Review on Vaccine Mechanisms, Results of Clinical Trials, Vaccinal Coverage and Interactions with Novel Variants

2021 ◽  
Vol 28 ◽  
Author(s):  
Douglas Henrique Pereira Damasceno ◽  
Arthur Aguiar Amaral ◽  
Cecília Andrade Silva ◽  
Ana Cristina Simões e Silva
Keyword(s):  
Immune Response ◽  
Clinical Trials ◽  
Placebo Group ◽  
Mechanisms Of Action ◽  
Novel Variants ◽  
The Impact ◽  
Positive Results ◽  
Epidemiological Information ◽  
Long Term Studies

Background: The COVID-19 pandemic demanded a global effort towards quickly developing safe and effective vaccines against SARS-CoV-2. Objective: This review aimed to discuss the main vaccines available, their mechanisms of action, results of clinical trials and epidemiological behavior. The implications of viral variants were also debated. Methods: A non-systematic literature review was performed between February and March 2021 by searching the Pubmed, Scopus, and SciELO databases, using different combinations of the following terms: "vaccines", "clinical trials" , "SARS-CoV-2", "Coronavirus", "COVID-19", "mechanisms of action". Data regarding clinical trials of SARS-CoV-2 vaccines and epidemiological information were also searched. Results: The mechanisms of action included vector-virus, mRNA and inactivated virus vaccines. The vaccines showed positive results in phases 2/3 clinical trials. The efficacy of the mRNA 1273 and of mRNA BNT 162b2 vaccines were 94.1% and 95%, respectively. The effectiveness of the ChAdOx1 nCoV-19 vaccine varied according to the scheme, with an overall value of 70.4%. The Gam-COVID-Vac vaccine had an efficacy of 91.6%. Regarding the Ad26.COV2.S vaccine, 99% or more of seroconversion was observed in all subgroups 29 days after vaccination. The CoronaVac vaccine induced an immune response in 92% of the volunteers receiving 3ug and in 98% with 6ug, in comparison to 3% in the placebo group. Conclusion: Global efforts have resulted in vaccines available in record time, with good safety and immunogenicity profile. However, only long-term studies can provide more information on duration of immunity and the need for additional doses.

Clinical features, treatment, and outcome of dogs with Coccidioides osteomyelitis

2022 ◽  
pp. 1-8
Author(s):  
Stephanie L. Shaver ◽  
Daniel S. Foy ◽  
Todd D. Carter
Keyword(s):  
Electronic Medical Records ◽  
Medical Records ◽  
Clinical Signs ◽  
Test Results ◽  
Serologic Test ◽  
Rapid Improvement ◽  
Radiographic Appearance ◽  
One Year ◽  
Positive Results

Abstract OBJECTIVE To describe signalment, clinical signs, serologic test results, treatment, and outcome of dogs with Coccidioides osteomyelitis (COM) and to compare those findings with findings for dogs with osteosarcoma (OSA). ANIMALS 14 dogs with COM and 16 dogs with OSA. PROCEDURES Data were retrospectively gathered from electronic medical records. RESULTS Dogs with COM were younger and weighed less than dogs with OSA. Six dogs with COM had appendicular lesions, 5 had axial lesions, and 3 had both appendicular and axial lesions; 9 had monostotic disease, and 5 had polyostotic disease. Axial lesions and nonadjacent polyostotic disease were more common in dogs with COM than in dogs with OSA, but radiographic appearance was not different between the 2 groups. Median IgG titer at diagnosis of COM was 1:48 and was significantly decreased after 6 and 12 months of treatment. Percentage of dogs with COM that had clinical signs was significantly decreased after 1, 3, 6, and 12 months of treatment. One year after initiation of treatment, 9 of 9 dogs were still receiving fluconazole and 8 of 9 dogs had positive results for serum IgG titer testing. CLINICAL RELEVANCE Dogs with COM typically had a rapid improvement in clinical signs after initiating treatment with fluconazole but required long-term antifungal treatment. Dogs with COM differed from dogs with OSA, but radiographic features had a great degree of overlap between groups, confounding the ability to make a diagnosis on the basis of diagnostic imaging alone.

Organization of the work of the inter-republican phoniatric centre

1995 ◽  
Vol 76 (1) ◽  
pp. 70-71
Author(s):  
H. A. Alimetov ◽  
A. Y. Dovgalyuk ◽  
A. I. Raupov ◽  
L. A. Ziatdinova
Keyword(s):  
Combined Treatment ◽  
Structural Elements ◽  
Quantitative Characteristics ◽  
Positive Results

The structure, equipment and staff of the phoniatric centre are presented. The experience of the work from 1988 to 1993 is generalized. The quantitative characteristics of the work of polyclinic department of the centre and hospital, pointing to the significant, nearly 3 times, increase of the patients number taking phoniatric help in the dynamics are given. The combined treatment (microsurgical correction of structural elements of the larynx, phoniatric, logopedic, psychotherapeutic effect methods) allows to achieve positive results.

scholarly journals Rapid evolution of decreased host susceptibility drives a stable relationship between ultrasmall parasite TM7x and its bacterial host

2018 ◽  
Vol 115 (48) ◽  
pp. 12277-12282 ◽  
Author(s):  
Batbileg Bor ◽  
Jeffrey S. McLean ◽  
Kevin R. Foster ◽  
Lujia Cen ◽  
Thao T. To ◽  
...  
Keyword(s):  
Host Cell ◽  
Rapid Evolution ◽  
Host Population ◽  
Host Cells ◽  
Host Susceptibility ◽  
Bacterial Host ◽  
Narrow Host Range ◽  
Stable Relationship ◽  
Candidate Phyla Radiation

Around one-quarter of bacterial diversity comprises a single radiation with reduced genomes, known collectively as the Candidate Phyla Radiation. Recently, we coisolated TM7x, an ultrasmall strain of the Candidate Phyla Radiation phylum Saccharibacteria, with its bacterial host Actinomyces odontolyticus strain XH001 from human oral cavity and stably maintained as a coculture. Our current work demonstrates that within the coculture, TM7x cells establish a long-term parasitic association with host cells by infecting only a subset of the population, which stay viable yet exhibit severely inhibited cell division. In contrast, exposure of a naïve A. odontolyticus isolate, XH001n, to TM7x cells leads to high numbers of TM7x cells binding to each host cell, massive host cell death, and a host population crash. However, further passaging reveals that XH001n becomes less susceptible to TM7x over time and enters a long-term stable relationship similar to that of XH001. We show that this reduced susceptibility is driven by rapid host evolution that, in contrast to many forms of phage resistance, offers only partial protection. The result is a stalemate where infected hosts cannot shed their parasites; nevertheless, parasite load is sufficiently low that the host population persists. Finally, we show that TM7x can infect and form stable long-term relationships with other species in a single clade of Actinomyces, displaying a narrow host range. This system serves as a model to understand how parasitic bacteria with reduced genomes such as those of the Candidate Phyla Radiation have persisted with their hosts and ultimately expanded in their diversity.

scholarly journals Evaluation of Polymerization shrinkage of 2 types of posterior composite resins

2017 ◽  
Vol 07 (01) ◽  
pp. 025-028
Author(s):  
Lakshmi Nidhi Rao ◽  
Mithra N. Hegde ◽  
Aditya Shetty
Keyword(s):  
Clinical Outcome ◽  
T Test ◽  
Composite Resins ◽  
Restorative Material ◽  
Restorative Dentistry ◽  
Posterior Teeth ◽  
Polymerization Shrinkage ◽  
Glass Fibres ◽  
First Choice ◽  
Significant Difference

AbstractComposite resins represent a class of material widely used in restorative dentistry, not only for anterior aesthetics but also as the first choice to restore posterior teeth. However the key limitation in the use of composite resins as a restorative material is related to shrinkage during polymerization which leads to poor marginal seal, marginal staining, restoration displacement, tooth fracture and recurring caries [1].Polymerization shrinkage may affect negatively the clinical outcome of the restoration. Hence the present study evaluates the Polymerization shrinkage of 2 different posterior composites; Filtek Z350(3M) and everX Posterior(GC), using a pycnometer.Independent Sample T-Test was used to determine statistically significant difference in volumetric shrinkage among the tested composite resins. everX Posterior showed comparatively less shrinkage than Filtek Z350; which can be attributed to the presence of silanated e-glass fibres.

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