scholarly journals Does etching time affect the in vitro performance of a sealant material?

2020 ◽  
Vol 39 (5) ◽  
pp. 862-868
Author(s):  
Yi-Fang LO ◽  
Vinay PITCHIKA ◽  
Nicoleta ILIE ◽  
Reinhard HICKEL ◽  
Jan KÜHNISCH
Keyword(s):  
Etching Time ◽  
Sealant Material

scholarly journals Influência do tempo de condicionamento do ácido hidrofluorídrico na adesão protética de cerâmicas vítreas: uma revisão sistemática

2021 ◽  
Vol 10 (2) ◽  
pp. e18819212240
Author(s):  
Laís Ferrante de Faria ◽  
Millena Silva Cardoso ◽  
Camila Moreira Lima ◽  
Laércio Almeida de Melo ◽  
Fabíola Pessôa Pereira Leite
Keyword(s):  
Systematic Reviews ◽  
Evidence Based Medicine ◽  
Hydrofluoric Acid ◽  
Web Of Science ◽  
Cochrane Library ◽  
Etching Time ◽  
Evidence Based ◽  
Application Time ◽  
Based Medicine

Objetivo: Objetivou-se avaliar a influência do tempo de condicionamento do Ácido Hidrofluorídrico (HF) em diferentes cerâmicas vítreas, a fim de estabelecer o melhor protocolo que viabilize uma adequada adesão protética do material restaurador. Metodologia: Trata-se de uma revisão sistemática de estudos in vitro. Para a sua realização, utilizou-se os descritores “Veneers”, “Crowns”, “Ceramics”, “Ceramic”, “Etching Time”, “Application Time”, “Surface Treatments”, “Hydrofluoric Acid” e “Adhesion” nas bases Scopus, PubMed, Cochrane Library, SciElo, Web of Science e Lilacs. Estudos que investigaram os efeitos do tempo de aplicação do HF sobre a adesão de cerâmicas vítreas foram incluídos. O nível de evidência dos artigos selecionados seguiu os princípios do Oxford Center for Evidence-Based Medicine. Esta revisão seguiu as recomendações do Preferred Reporting Items for Systematic Reviews and Meta-analyzes (PRISMA). Resultados: A estratégia de busca resultou em 290 estudos, dos quais 5 foram incluídos na revisão. Os estudos demonstraram diferentes parâmetros avaliativos como rugosidade microestrutural, molhabilidade, resistência ao cisalhamento, resistência à flexão biaxial e microdureza das cerâmicas, a fim de investigar a influência do tempo de condicionamento do HF nas cerâmicas vítreas, incluindo feldspáticas, de silicato de lítio reforçada por zircônia e dissilicato de lítio. O condicionamento com HF por 60s é recomendado para cerâmicas feldspáticas, enquanto para cerâmicas de silicato de lítio reforçada por zircônia e de dissilicato de lítio é indicado por 20s. Conclusão: O tempo de condicionamento da cerâmica com HF influencia na adesão. Tempos prolongados de condicionamento são prejudiciais às cerâmicas vítreas, refletindo em redução da adesão protética.

Simultaneous Observation of Cells and Nuclear Tracks from the Boron Neutron Capture Reaction by UV-C Sensitization of Polycarbonate

2015 ◽  
Vol 21 (4) ◽  
pp. 796-804 ◽  
Author(s):  
Agustina Portu ◽  
Andrés Eugenio Rossini ◽  
Silvia Inés Thorp ◽  
Paula Curotto ◽  
Emiliano César Cayetano Pozzi ◽  
...  
Keyword(s):  
Neutron Capture ◽  
Etching Time ◽  
Boron Uptake ◽  
Etch Pits ◽  
Nuclear Track Detector ◽  
Boron Neutron Capture ◽  
Precise Knowledge ◽  
Nuclear Tracks ◽  
Uv C

AbstractThe distribution of boron in tissue samples coming from boron neutron capture therapy protocols can be determined through the analysis of its autoradiography image on a nuclear track detector. A more precise knowledge of boron atom location on the microscopic scale can be attained by the observation of nuclear tracks superimposed on the sample image on the detector. A method to produce an “imprint” of cells cultivated on a polycarbonate detector was developed, based on the photodegradation properties of UV-C radiation on this material. Optimal conditions to generate an appropriate monolayer of Mel-J cells incubated with boronophenylalanine were found. The best images of both cells and nuclear tracks were obtained for a neutron fluence of 1013 cm−2, 6 h UV-C (254 nm) exposure, and 4 min etching time with a KOH solution. The imprint morphology was analyzed by both light and scanning electron microscopy. Similar samples, exposed to UV-A (360 nm) revealed no cellular imprinting. Etch pits were present only inside the cell imprints, indicating a preferential boron uptake (about threefold the incubation concentration). Comparative studies of boron absorption in different cell lines and in vitro evaluation of the effect of diverse boron compounds are feasible with this methodology.

scholarly journals Oxidative nanopatterning of titanium surfaces promotes production and extracellular accumulation of osteopontin

2011 ◽  
Vol 22 (3) ◽  
pp. 179-184 ◽  
Author(s):  
Renan de Barros e Lima Bueno ◽  
Patricia Adachi ◽  
Larissa Moreira Spinola de Castro-Raucci ◽  
Adalberto Luiz Rosa ◽  
Antonio Nanci ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Etching Time ◽  
Calvarial Bone ◽  
Multifunctional Protein ◽  
Osteogenic Cells ◽  
Biomaterial Surfaces ◽  
Titanium Surfaces ◽  
Nanoporous Surface ◽  
Physical And Chemical

The bone-biomaterial interface has been characterized by layers of afibrillar extracellular matrix (ECM) enriched in non collagenous proteins, including osteopontin (OPN), a multifunctional protein that in bone controls cell adhesion and ECM mineralization. Physical and chemical aspects of biomaterial surfaces have been demonstrated to affect cell-ECM-substrate interactions. The present paper described the ability of oxidative nanopatterning of titanium (Ti) surfaces to control extracellular OPN deposition in vitro. Ti discs were chemically treated by a mixture of H2SO4/H2O2 for either 30 min [Nano(30') Ti] or 4 h [Nano(4h) Ti]. Non-etched Ti discs were used as control. Primary osteogenic cells derived from newborn rat calvarial bone were plated on control and etched Ti and grown under osteogenic conditions up to 7 days. High resolution scanning electron microscopy revealed that treated Ti discs exhibited a nanoporous surface and that areas of larger nanopits were noticed only for Nano(4h) Ti. Large extracellular OPN accumulation were detectable only for Nano(4h) Ti, which was associated with OPN-positive cells with typical aspects of migrating cells. At day 3, quantitative results in terms of areas of OPN labeling were as follows: Nano(4h) Ti > Nano(30') Ti > Control Ti. In conclusion, chemically nanostructured Ti surfaces may support the enhancement of endogenous extracellular OPN deposition by osteogenic cells in vitro depending on the etching time, a finding that should be taken into consideration in strategies to biofunctionalize implant surfaces with molecules with cell adhesion capacity.

scholarly journals Optimal acidulated phosphate fluoride gel etching time for surface treatment of feldspathic porcelain: on shear bond strength to resin composite

2012 ◽  
Vol 06 (01) ◽  
pp. 063-069 ◽  
Author(s):  
Boonlert Kukiattrakoon ◽  
Kewalin Thammasitboon
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
Resin Composite ◽  
In Vitro Study ◽  
Etching Time ◽  
Control Group ◽  
Gel Treatment ◽  
Feldspathic Porcelain ◽  
Treatment Control Group

ABSTRACTObjectives: This in vitro study evaluated the shear bond strength (SBS) of resin composite to feldspathic porcelain after acidulated phosphate fluoride (APF) gel treatment over different periods of timeMethods: One hundred and fifty-six feldspathic specimens were divided into 12 groups. Group C received no treatment (control group). Groups APF1 through APF10, ten experimental groups, were treated with 1.23% APF gel. Each group obtained 1 to 10 minutes of etching time in 1 minute increments, respectively. Group HF2 was treated with 9.6% hydrofluoric acid (HF) for 2 minutes. All specimens were then bonded to a resin composite cylinder using Adper Scotchbond Multi-purpose (3M ESPE) after silane (Monobond-S, Ivoclar Vivadent AG) application. Specimens were stored at 37ºC for 24 hours before the SBS was performed and were recorded in MPa at fracture. Data were analyzed using one-way ANOVA and Tukey’s test (α=.05)Results: HF etching yielded the highest SBS (18.0 ± 1.5 MPa), which was not significantly different from APF gel etching for 6 to 10 minutes (16.0 ± 2.1 to 17.2 ± 1.6 MPa) (P>.05)Conclusions: APF gel etching for 6 minutes might be used as an alternative etchant to HF acid for bonding resin composite to silanized feldspathic porcelain. (Eur J Dent 2012;6:63-69)

Ultrastructural Investigations of the Contractile Filaments of Amoebae

1974 ◽  
Vol 32 ◽  
pp. 188-189
Author(s):  
P.L. Moore
Keyword(s):  
Cytoplasmic Streaming ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Amoeboid Movement ◽  
Different Types ◽  
Chemical Conditions ◽  
Complete Interpretation

Previous freeze fracture results on the intact giant, amoeba Chaos carolinensis indicated the presence of a fibrillar arrangement of filaments within the cytoplasm. A complete interpretation of the three dimensional ultrastructure of these structures, and their possible role in amoeboid movement was not possible, since comparable results could not be obtained with conventional fixation of intact amoebae. Progress in interpreting the freeze fracture images of amoebae required a more thorough understanding of the different types of filaments present in amoebae, and of the ways in which they could be organized while remaining functional.The recent development of a calcium sensitive, demembranated, amoeboid model of Chaos carolinensis has made it possible to achieve a better understanding of such functional arrangements of amoeboid filaments. In these models the motility of demembranated cytoplasm can be controlled in vitro, and the chemical conditions necessary for contractility, and cytoplasmic streaming can be investigated. It is clear from these studies that “fibrils” exist in amoeboid models, and that they are capable of contracting along their length under conditions similar to those which cause contraction in vertebrate muscles.

In Vitro Induction of Crystals of MT Protein by Vinblastine-Colcemid in Mouse Spermatids

1974 ◽  
Vol 32 ◽  
pp. 132-133
Author(s):  
John J. Wolosewick ◽  
John H. D. Bryan
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Endoplasmic Reticulum ◽  
Nuclear Ring ◽  
Rough Er ◽  
Distal Direction ◽  
In Vitro Induction

Early in spermiogenesis the manchette is rapidly assembled in a distal direction from the nuclear-ring-densities. The association of vesicles of smooth endoplasmic reticulum (SER) and the manchette microtubules (MTS) has been reported. In the mouse, osmophilic densities at the distal ends of the manchette are the organizing centers (MTOCS), and are associated with the SER. Rapid MT assembly and the lack of rough ER suggests that there is an existing pool of MT protein. Colcemid potentiates the reaction of vinblastine with tubulin and was used in this investigation to detect this protein.

Induction and Differentiation of Dental Epithelium in Vivo and in Vitro

1982 ◽  
Vol 40 ◽  
pp. 142-145
Author(s):  
E. J. Kollar
Keyword(s):  
Connective Tissue ◽  
Oral Mucosa ◽  
Basal Lamina ◽  
Functional Derivatives ◽  
Specific Source ◽  
Dental Epithelium ◽  
Connective Tissue Stroma

The differentiation and maintenance of many specialized epithelial structures are dependent on the underlying connective tissue stroma and on an intact basal lamina. These requirements are especially stringent in the development and maintenance of the skin and oral mucosa. The keratinization patterns of thin or thick cornified layers as well as the appearance of specialized functional derivatives such as hair and teeth can be correlated with the specific source of stroma which supports these differentiated expressions.

Immunoenzymatic demonstration of the simultaneous presence of transferrin, hemopexin and albumin in a same hepatocyte and their ultrastructural localization

1978 ◽  
Vol 36 (2) ◽  
pp. 88-89
Author(s):  
M. Kraemer ◽  
J. Foucrier ◽  
J. Vassy ◽  
M.T. Chalumeau
Keyword(s):  
Plasma Proteins ◽  
Rat Hepatocytes ◽  
Ultrastructural Localization ◽  
Carrier Proteins ◽  
Normal Cells ◽  
Adult Rat ◽  
Adult Rat Hepatocytes ◽  
Monospecific Antisera ◽  
Different Levels

Some authors using immunofluorescent techniques had already suggested that some hepatocytes are able to synthetize several plasma proteins. In vitro studies on normal cells or on cells issued of murine hepatomas raise the same conclusion. These works could be indications of an hepatocyte functionnal non-specialization, meanwhile the authors never give direct topographic proofs suitable with this hypothesis.The use of immunoenzymatic techniques after obtention of monospecific antisera had seemed to us useful to bring forward a better knowledge of this problem. We have studied three carrier proteins (transferrin = Tf, hemopexin = Hx, albumin = Alb) operating at different levels in iron metabolism by demonstrating and localizing the adult rat hepatocytes involved in their synthesis.Immunological, histological and ultrastructural methods have been described in a previous work.

Sem Studies of Co-Cr-Mo Surgical Implant Alloy Corrosion Behavior

1982 ◽  
Vol 40 ◽  
pp. 520-521
Author(s):  
Ann Chidester Van Orden ◽  
John L. Chidester ◽  
Anna C. Fraker ◽  
Pei Sung
Keyword(s):  
Electron Microscopy ◽  
Corrosion Behavior ◽  
Anodic Polarization ◽  
Saline Solution ◽  
Saturated Calomel Electrode ◽  
Physiological Saline ◽  
X Ray ◽  
Physiological Saline Solution ◽  
Scanning Electron

The influence of small variations in the composition on the corrosion behavior of Co-Cr-Mo alloys has been studied using scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), and electrochemical measurements. SEM and EDX data were correlated with data from in vitro corrosion measurements involving repassivation and also potentiostatic anodic polarization measurements. Specimens studied included the four alloys shown in Table 1. Corrosion tests were conducted in Hanks' physiological saline solution which has a pH of 7.4 and was held at a temperature of 37°C. Specimens were mechanically polished to a surface finish with 0.05 µm A1203, then exposed to the solution and anodically polarized at a rate of 0.006 v/min. All voltages were measured vs. the saturated calomel electrode (s.c.e.).. Specimens had breakdown potentials near 0.47V vs. s.c.e.

Sign in / Sign up

Export Citation Format

Share Document