A BSTRACT Objective: The electrochemical dissolution method of instrument retrieval emphasizes on the dissolution of the instrument rather than sacrificing dentine. Most of the studies conducted for ...electrochemical dissolution used fluoride-containing electrolytes and were performed inside a beaker. In this study, we used chloride-based fluids as electrolytes. Materials and Methods: Fifty extracted mandibular first premolars were divided into five groups based on the electrolytes used. Canals were enlarged to ProTaper Universal F2, and files were intentionally broken inside the canal. These specimens were subjected to electrochemical characterization by applying the potential of 9V for 20 min. Optical images were taken to assess the change in surface topography. The results were analyzed statistically by one-way analysis of variance (analysis of variance ANOVA). Results: The rate of dissolution based on the electrolyte used decreased in the following order, viz. Tyrode’s solution>artificial saliva>normal saline>Ringer’s lactate/physiological serum. Conclusion: Apart from fluoride, chloride-based electrolytes could be an efficient alternative.
The aim of the present work was measuring the effect of varying normal forces on frictional forces applied to different bracket types in combination with archwires made of NiTi and stainless steel of ...variable cross section. The measurements were carried out in artificial saliva. Three-way ANOVA and Bonferroni post-hoc tests (α=0.05) were applied. Except for one subgroup the combination of normal force, bracket system and wire dimension had significant effect on friction (p<0.001) as friction increased with increasing normal forces. Only moderately tied ligatures or passive self-ligating brackets generate low friction forces. There was a statistically significant order (0.016"×0.022"<0.018"×0.025"<0.019"×0.025") for stainless steel wire material. Finite element modeling simulation showed the increasing effect of active clip force on friction especially for 0.025" wire profiles. If compared to NiTi wires, stainless steel archwires delivered higher friction. Combinations between wire-type and ligation should be chosen carefully for the intended treatment step.
Distilled water with NaHCO3 and KCl is a solution often referred to as ‘artificial saliva’ because its chemical composition mimics human saliva. It is often used as a control stimulus in gustatory ...research, especially in neuroimaging, owing to the claim that it does not produce a response in primary gustatory cortex Yet evidence that human research volunteers perceive this liquid as affectively neutral is lacking. Unpublished data from our lab suggested that this solution might be perceived as aversive. This study set out to systematically test the parameters influencing taste neutrality. We used two different concentrations of distilled water with NaHCO3 and KCl, as well as bottled water as a control stimulus. Healthy adults rated all stimuli on two separate scales to rule out an interpretation based on the specifics of a single scale. Our participants rated artificial saliva as aversive on both scales. The bottled water was rated as neutral in valence on both scales, and as significantly less intense in sensation than both concentrations of the artificial saliva. This is the first study to have directly tested the subjective feelings that accompany the ingestion of these oft-used solutions on a trial-by-trial basis. We found that these stimuli, which were previously assumed to be neutral, may not be perceived as such by research participants. Therefore, future gustatory studies should take care when using this solution as a neutral baseline. It is advised that trial-by-trial ratings are collected. Also, depending on the nature of future studies, bottled water may be considered as a preferable neutral baseline.
In the present study, we have developed a capacitance electrochemical biosensor based on silicon nitride substrate (Si3N4/SiO2/SiP/Al) for Tumour Necrosis Factor Alpha (TNF-α) cytokines detection. ...Micro-contact printing, Fluorescence microscopy characterization and contact angle measurement (CAM) were carried out during the bio-functionalization of the biosensor surface. Mott-Schottky analyses were applied for TNF-α detection within the range of 1 pg/mL to 30 pg/mL in which the immunosensor has exhibited a good linearity, a sensitivity of 4 mV.pM−1 and 4.4 mV.pM−1 in PBS and artificial saliva (AS) respectively. While the LOD was found at 0.38 pg/mL and 1 pg/mL in PBS and AS respectively. The developed immunosensor has also demonstrated a high and good selectivity for TNF-α detection in human AS when compared to other interferences like Cortisol and Interleukin-10. The performances of the developed biosensor are very promising for biomedical application to predict the first sign of inflammation.
Schematic illustrations of the chemical surface modification and bio-functionalization process of the immunosensor with antibodies Anti-TNF-α. Display omitted
•Fabrication of a capacitance electrochemical immunosensor based on silicon nitride transducer (Si3N4/SiO2/SiP/Al).•Silicon nitride surface was activated and chemically modified with TESUD to immobilize antibodies Anti-TNF-α.•µCP, Fluorescence microscopy and CAM measurement were carried out during the bio-functionalization of the biosensor surface.•Biosensor has exhibited a high sensitivity and a good selectivity for TNF-α cytokines when compared to IL-10 and Cortisol.•Interesting LOD of TNF-α cytokines was found at 0.38 pg/mL in PBS and 1pg/mL-1 in AS.
•Comparison of CoCr alloy manufactured by selective laser melting and by casting.•Study of ion release into artificial saliva, with added fluoride ions or low pH.•Ion release was highest in acidic ...environment.•Long term EIS showed better performance for casted specimens.•Surface condition played important role for ion release and corrosion.
The aim of this study was to compare corrosion resistance and ion release in CoCr dental alloys with identical chemical compositions produced using different technologies (SLM – selective laser melting and milling from cast blocks) and heat treatment (SLM parts only). The corrosion properties were tested in artificial saliva, artificial saliva with fluoride ions, and artificial saliva with added lactic acid to simulate inflammations. The study included electrochemical tests, microstructural investigation and ion release tests in the three different environments for a total of 42 days. The best performance of CoCr as a result of potentiodynamic polarization was observed in the artificial saliva with added lactic acid, which is in contradiction with the highest ion release measured from all the materials tested and electrochemical impedance spectroscopy that showed a deterioration of the passive layer in an acidic environment. Microstructural investigation revealed that different phases precipitated by heat treatment trigger increased release of Mo and W ions. The printing method does not raise critically ion release from CoCr alloy, while the state of the surface greatly impacts the extent of the ion release. This study demonstrates the importance of an interdisciplinary approach to the study of corrosion and biocompatibility in dental alloys.
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Artificial saliva and its use in biological experiments J Pytko-Polonczyk, J; Jakubik, A; Przeklasa-Bierowiec, A ...
Journal of physiology and pharmacology : an official journal of the Polish Physiological Society
68, Številka:
6
Journal Article
Recenzirano
Examination of dental materials and their properties at the initial stage of the digestive process requires the development of conditions that mimic the environment of the oral cavity. One of the ...main components of this area is saliva, where many reactions occur under natural conditions. Human saliva is an important physiological fluid that is essential for the maintenance of good oral health and of the entire human body; it is the place where digestion begins and thus contributes to the supply of those nutrients and health-promoting substances that are essential to the body but may also cause release of potential toxins. Thereby, the main aim of the study was to review the use of artificial saliva models in the context of stomatological and biological research. Biological studies have shown that the amount of biologically active substances in biological material is not the same as their quantity released under the conditions of the human digestive system and thus bioavailable to it. These results show that tables of active ingredients in drugs and food stuffs do not present their actual usefulness and availability to the human body.
Biphasic calcium phosphate (BCP) is an ideal bone substitute with controllable bioresorption/biodegradation by changing its relative amount of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) ...compositions. This study investigated the effect of synthetic conditions on the physicochemical properties and the remineralization behaviors of BCP materials in artificial saliva (AS). BCPs were obtained under the sonochemical condition at pH of 5.0 (BCP_5), 7.0 (BCP_7), and 9.0 (BCP_9), and all were sintered at 800, 1000, and 1200 °C. The HA/β-TCP ratio of BCPs increased according to the pH increase during the synthesis process. BCP_5 sintered at 800 °C with the highest β-TCP contents demonstrated (1) fast neutralization capacity to prevent enamel from dissolving in acidic saliva and (2) remineralization ion supply, and (3) new apatite formation found in acidic AS, indicating its high potential remineralization agent for dental care applications.
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•BCPs synthesized at pH 5.0 with high β-TCP had fast neutralization capacity in acidic saliva and ion supply.•BCPs synthesized at pH 5.0 generated new apatite formation in acidic and neutral artificial saliva.•BCPs sintered at 800 and 1000 °C achieved better remineralization properties than 1200 °C.
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