scholarly journals Resin-modified Glass-ionomer Setting Reaction Competition

2009 ◽  
Vol 89 (1) ◽  
pp. 82-86 ◽  
Author(s):  
D.W. Berzins ◽  
S. Abey ◽  
M.C. Costache ◽  
C.A. Wilkie ◽  
H.W. Roberts
Keyword(s):  
Differential Scanning Calorimetry ◽  
The Other ◽  
Glass Ionomer ◽  
Light Activation ◽  
Acid Base ◽  
Scanning Calorimetry ◽  
Setting Reaction ◽  
Resin Modified Glass Ionomer ◽  
Light Curing ◽  
Setting Mechanism

Resin-modified glass ionomers (RMGI) set by at least 2 mechanisms dependent upon reactant diffusion prior to gelation. Each reaction’s kinetics and setting mechanism may rely on and/or compete with the other. In this study, we investigated RMGI setting reaction interactions using differential scanning calorimetry (DSC) by varying light-cure initiation times. A RMGI was analyzed with isothermal and dynamic temperature scan DSC with light-curing occurring immediately, or at 5 or 10 minutes after mixing as well as without light-activation. Results show that as time allowed for the acid-base reaction increased, the light-activation polymerization exotherm decreased. Conversely, analysis of DSC data suggests that earlier light-activation may limit the acid-base reaction and result in a different structured material. During early RMGI development, acid-base and light-polymerization reactions compete with and inhibit one another.

Effect of Light Activation on Resin-modified Glass Ionomer Shear Bond Strength

2012 ◽  
Vol 37 (4) ◽  
pp. 380-385 ◽  
Author(s):  
NC Lawson ◽  
D Cakir ◽  
P Beck ◽  
L Ramp ◽  
JO Burgess
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
Glass Ionomer ◽  
Light Activation ◽  
Plastic Tube ◽  
Significant Difference ◽  
Resin Modified Glass Ionomer ◽  
Light Curing ◽  
Setting Mechanism ◽  
Effect Of Light

SUMMARY Objective Recent studies confirmed that resin-modified glass ionomers (RMGIs) set on the basis of two competing mechanisms, an acid-base reaction and a light-activated resin polymerization. This study evaluated the effect of the setting mechanism on bond strength by measuring the shear bond strength of three RMGIs to dentin with and without light activation. Methods Sixty human molars were ground to midcoronal dentin and randomly divided into six even groups: 1) Ketac Nano (KN), 2) KN without light cure (woLC), 3) Fuji Filling LC (FF), 4) FF woLC, 5) Fuji II LC (FII), and 6) FII woLC. The dentin surfaces of the specimens were conditioned/primed according to the manufacturers' instructions. A 1.54-mm diameter plastic tube was filled with RMGI material and affixed to the dentin surface. Groups 1, 3, and 5 were light cured for 20 seconds, and groups 2, 4, and 6 were immediately placed in a damp dark box with no light curing at 37°C for 24 hours. Shear bond strength testing was performed in an Instron device at 1 mm/min. Data were analyzed with a one-way analysis of variance (ANOVA) and Tukey/Kramer test (α=0.05). Results Mean ± standard deviation shear bond strength values (MPa) are: 7.1 ± 4.2 (KN), 11.7 ± 3.9 (FF), 10.2 ± 3.2 (FF woLC), 12.5 ± 5.1 (FII), and 0.3 ± 0.4 (FII woLC). Two KN, all KN woLC, and seven FII woLC specimens debonded before testing. Tukey/Kramer analysis revealed no significant differences in bond strength between the three light-cured RMGIs. KN and FII showed significantly lower bond strength without light cure, but no significant difference was observed between FF and FF woLC. Conclusions The results of this study strongly suggest that light activation is necessary to obtain optimal bond strength between RMGI and dentin. FF may contain components that chemically activate resin polymerization. Clinically, KN and FII need to be light cured after placement of these RMGIs.

scholarly journals Setting Reaction of Dental Resin-Modified Glass Ionomer Restoratives as a Function of Curing Depth and Postirradiation Time

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Young Kyung Kim ◽  
Kyo-Han Kim ◽  
Tae-Yub Kwon
Keyword(s):  
Ftir Spectroscopy ◽  
Glass Ionomer ◽  
Acid Base ◽  
Dental Resin ◽  
Setting Reaction ◽  
Specular Reflectance ◽  
Custom Made ◽  
Resin Modified Glass Ionomer ◽  
Different Depths ◽  
Curing Light

Specular reflectance Fourier transform infrared (SR-FTIR) spectroscopy was used to study the setting reaction of dental resin-modified glass ionomer (RMGI) restoratives as a function of curing depth and postirradiation time. Two light-cure and one tri-cure RMGI materials were selected and used according to the manufacturers’ instructions. Samples were prepared by filling the mixed materials into custom-made molds and then light-irradiating using a dental curing light. The degree of conversion and the extent of acid-base reaction of the materials at different depths (0, 1, 2, and 4 mm) and postirradiation times (10 min, 1 day, and 7 days) were determined using SR-FTIR spectroscopy in conjunction with the Kramers-Kronig (K-K) transformation. The setting reaction was also investigated using microhardness measurements. The results showed that the depth of cure increased over time by the continuous acid-base reaction rather than photopolymerization or chemical polymerization. Microhardness tests seemed less suitable for studying the setting reaction as a function of postirradiation time, probably due to softening from the humidity. Analysis using specular reflectance in conjunction with the K-K algorithm was an easy and effective method for monitoring the setting reaction of dental RMGI materials.

scholarly journals Intrapulpal Thermal Changes during Setting Reaction of Glass Carbomer® Using Thermocure Lamp

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Firdevs Kahvecioglu ◽  
Gül Tosun ◽  
Hayriye Esra Ülker
Keyword(s):  
Composite Resin ◽  
Permanent Teeth ◽  
Glass Ionomer ◽  
Data Logger ◽  
Setting Reaction ◽  
Honestly Significant Difference ◽  
Significant Difference ◽  
Resin Modified Glass Ionomer ◽  
Permanent Molars ◽  
Light Curing

Objectives. To measure the temperature increase induced during thermocure lamp setting reaction of glass carbomer and to compare it with those induced by visible light curing of a resin-modified glass ionomer and a polyacid-modified composite resin in primary and permanent teeth. Materials and Methods. Nonretentive class I cavities were prepared in extracted primary and permanent molars. Glass carbomer (GC) was placed in the cavity and set at 60°C for 60 sn using a special thermocure lamp. Resin-modified glass ionomer (RMGIC) and polyacid-modified composite resin (PMCR) were placed in the cavities and polymerized with an LED curing unit. Temperature increases during setting reactions were measured with a J-type thermocouple wire connected to a data logger. Data were examined using two-way analysis of variance and Tukey’s honestly significant difference tests. Results. The use of GC resulted in temperature changes of 5.17 ± 0.92°C and 5.32 ± 0.90°C in primary and permanent teeth, respectively (p>0.05). Temperature increases were greatest in the GC group, differing significantly from those in the PMCR group (p<0.05). Conclusion. Temperature increases during polymerization and setting reactions of the materials were below the critical value in all groups. No difference was observed between primary and permanent teeth, regardless of the material used.

scholarly journals Structural and long-term mechanical properties from a resin-modified glass ionomer cement after various delays of light-activation

2018 ◽  
Vol 37 (6) ◽  
pp. 874-879 ◽  
Author(s):  
Marianne LAGARDE ◽  
Philippe FRANCOIS ◽  
Stéphane LE GOFF ◽  
Jean-Pierre ATTAL ◽  
Elisabeth DURSUN
Keyword(s):  
Mechanical Properties ◽  
Glass Ionomer Cement ◽  
Glass Ionomer ◽  
Light Activation ◽  
Resin Modified Glass Ionomer ◽  
Ionomer Cement

scholarly journals Temperature changes in the pulp chamber induced by polymerization of resin-based dental restoratives following simulated direct pulp capping

2019 ◽  
Vol 73 (4) ◽  
pp. 239-248
Author(s):  
Violeta Petrovic ◽  
Jovana Stasic ◽  
Vojislav Komlenic ◽  
Tatjana Savic-Stankovic ◽  
Marina Latkovic ◽  
...  
Keyword(s):  
Calcium Hydroxide ◽  
Mineral Trioxide Aggregate ◽  
Glass Ionomer ◽  
Direct Pulp Capping ◽  
Pulp Chamber ◽  
Temperature Changes ◽  
Pulp Capping ◽  
Dental Restoratives ◽  
Resin Modified Glass Ionomer ◽  
Light Curing

The objective of this study was to measure temperature changes in the pulp chamber induced by polymerization of resin-based dental restoratives following a simulated procedure of direct pulp capping. Class I cavities with a microperforation at the pulp horn were prepared in extracted human molar teeth. The complete procedure of direct pulp capping and cavity restoration was performed with the root part of extracted teeth fixed in a water bath at 37 ?C. Mineral trioxide aggregate, bioactive dentin substitute or calcium-hydroxide paste were used as pulp capping materials. Cavities were restored with a light-cured or chemically-cured resin-modified glass ionomer, universal adhesive and a bulk-fill composite, cured with a high-intensity LED unit. Pulp capping materials caused a slight temperature decrease. Lower temperature increase was recorded during light-curing of the glass ionomer liner after direct capping with mineral trioxide aggregate and calcium-hydroxide than that recorded for the bioactive dentin substitute. Adhesive light-curing increased temperature in all groups with higher mean temperatures in groups with chemically-cured as compared to those for the light-cured glass ionomer liner. Direct pulp capping with mineral trioxide aggregate or calcium-hydroxide followed by the light-cured resin-modified glass ionomer liner and a bonded bulk-fill composite restoration induced temperature changes below the potentially adverse threshold of 42.5?C.

scholarly journals The Influence of the Nature of Redox-Active Moieties on the Properties of Redox-Active Ionic Liquids and on Their Use as Electrolyte for Supercapacitors

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6344
Author(s):  
Philipp S. Borchers ◽  
Patrick Gerlach ◽  
Yihan Liu ◽  
Martin D. Hager ◽  
Andrea Balducci ◽  
...  
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Binary Mixtures ◽  
Thermal Characteristics ◽  
The Other ◽  
Scanning Calorimetry ◽  
Imidazolium Ionic Liquids ◽  
Redox Active

In this work, two new redox-active ionic liquids, one based on 2,2,6,6-tetramethylpiperidine-N-oxide and the other based on 4,4′-bipyridine, are synthesized and characterized. A ferrocene-based redox-active ionic liquid is used for referencing the results. All ionic liquids are formed via salt-metathesis from halogenate to bis(trifluoromethylsulfonyl)imide. Their fundamental thermal characteristics are assessed with differential scanning calorimetry. While the imidazolium ionic liquids show no melting point, the phase transition is well observable for the viologen-based ionic liquid. The properties of the neat redox-active ionic liquids and of binary mixtures containing these ionic liquids (0.1 m) and 1-butyl-1-methyl pyrrolidinium-bis(trifluoromethylsulfonyl)imide have been investigated. Finally, the use of these binary mixtures in combination with activated carbon-based electrodes has been considered in view of the use of these redox-active electrolytes in supercapacitors.

scholarly journals Water sorption of resin-modified glass-ionomer cements photoactivated with LED

2006 ◽  
Vol 20 (4) ◽  
pp. 342-346 ◽  
Author(s):  
Daniela Francisca Gigo Cefaly ◽  
Linda Wang ◽  
Liliam Lucia Carrara Paes de Mello ◽  
Janaína Lima dos Santos ◽  
Jean Rodrigo dos Santos ◽  
...  
Keyword(s):  
Water Sorption ◽  
Resin Composite ◽  
Composite Resins ◽  
Glass Ionomer Cements ◽  
Glass Ionomer ◽  
Constant Mass ◽  
Light Emitting ◽  
Halogen Light ◽  
Resin Modified Glass Ionomer ◽  
Light Curing

The Light Emitting Diodes (LED) technology has been used to photoactivate composite resins and there is a great number of published studies in this area. However, there are no studies regarding resin-modified glass-ionomer cements (RMGIC), which also need photoactivation. Therefore, the aim of this study was to evaluate water sorption of two RMGIC photoactivated with LED and to compare this property to that obtained with a halogen light curing unit. A resin composite was used as control. Five specimens of 15.0 mm in diameter x 1.0 mm in height were prepared for each combination of material (Fuji II LC Improved, Vitremer, and Filtek Z250) and curing unit (Radii and Optilight Plus) and transferred to desiccators until a constant mass was obtained. Then the specimens were immersed into deionized water for 7 days, weighed and reconditioned to a constant mass in desiccators. Water sorption was calculated based on weight and volume of specimens. The data were analyzed by two-way ANOVA and Tukey test (p < 0.05). Specimens photocured with LED presented significantly more water sorption than those photocured with halogen light. The RMGIC absorbed statistically significant more water than the resin composite. The type of light curing unit affected water sorption characteristics of the RMGIC.

scholarly journals In Vitro Shear Bond Strength of Three Self-adhesive Resin Cements and a Resin-Modified Glass Ionomer Cement to Various Prosthodontic Substrates

2013 ◽  
Vol 38 (2) ◽  
pp. 186-196 ◽  
Author(s):  
Camila Sabatini ◽  
Manthan Patel ◽  
Eric D'Silva
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
Glass Ionomer Cement ◽  
Glass Ionomer ◽  
Resin Cements ◽  
Adhesive Resin ◽  
Setting Reaction ◽  
Resin Modified Glass Ionomer ◽  
Bond Strengths ◽  
Ionomer Cement

SUMMARY Objective To evaluate the shear bond strength (SBS) of three self-adhesive resin cements and a resin-modified glass ionomer cement (RMGIC) to different prosthodontic substrates. Materials and Methods The substrates base metal, noble metal, zirconia, ceramic, and resin composite were used for bonding with different cements (n=12). Specimens were placed in a bonding jig, which was filled with one of four cements (RelyX Unicem, Multilink Automix, Maxcem Elite, and FujiCEM Automix). Both light-polymerizing (LP) and self-polymerizing (SP) setting reactions were tested. Shear bond strength was measured at 15 minutes and 24 hours in a testing device at a test speed of 1 mm/min and expressed in MPa. A Student t-test and a one-way analysis of variance (ANOVA) were used to evaluate differences between setting reactions, between testing times, and among cements irrespective of other factors. Generalized linear regression model and Tukey tests were used for multifactorial analysis. Results Significantly higher mean SBS were demonstrated for LP mode relative to SP mode (p&lt;0.001) and for 24 hours relative to 15 minutes (p&lt;0.001). Multifactorial analysis revealed that all factors (cement, substrate, and setting reaction) and all their interactions had a significant effect on the bond strength (p&lt;0.001). Resin showed significantly higher SBS than other substrates when bonded to RelyX Unicem and Multilink Automix in LP mode (p&lt;0.05). Overall, FujiCEM demonstrated significantly lower SBS than the three self-adhesive resin cements (p&lt;0.05). Conclusions Overall, higher bond strengths were demonstrated for LP relative to SP mode, 24 hours relative to 15 minutes and self-adhesive resin cements compared to the RMGICs. Bond strengths also varied depending on the substrate, indicating that selection of luting cement should be partially dictated by the substrate and the setting reaction.

Amorphous iron oxide prepared by microwave heating

2000 ◽  
Vol 15 (10) ◽  
pp. 2176-2181 ◽  
Author(s):  
Oleg Palchik ◽  
Israel Felner ◽  
Gina Kataby ◽  
Aharon Gedanken
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Iron Oxide ◽  
Iron Pentacarbonyl ◽  
Microwave Oven ◽  
The Other ◽  
Scanning Calorimetry ◽  
Amorphous Iron ◽  
Domestic Microwave Oven ◽  
Crystalline Phase Transition

Amorphous iron oxide (Fe2O3) was prepared by the pyrolysis of iron pentacarbonyl [Fe(CO)5] in a modified domestic microwave oven in refluxing chlorobenzene as a solvent under air. The reaction time was 20 min. Partially separated particles of iron oxide, 2–3 nm in diameter, were obtained. The other part showed aggregated spheres with a diameter of 25–40 nm. Differential scanning calorimetry measurements showed an amorphous/crystalline phase transition at about 250 °C.

Setting Kinetics Observation of a Brushite Cement by FTIR and DSC

2006 ◽  
Vol 309-311 ◽  
pp. 837-840 ◽  
Author(s):  
M.P. Hofmann ◽  
A.M. Young ◽  
Showan N. Nazhat ◽  
Uwe Gbureck ◽  
J.E. Barralet
Keyword(s):  
Differential Scanning Calorimetry ◽  
Infrared Spectroscopy ◽  
Calcium Phosphate ◽  
Chemical Reaction ◽  
Calcium Phosphate Cement ◽  
Scanning Calorimetry ◽  
Time Resolved ◽  
Setting Reaction ◽  
Time Resolved Infrared Spectroscopy ◽  
First Time

Time resolved infrared spectroscopy (FTIR) and isothermal differential scanning calorimetry (DSC) were used for the first time to monitor the chemical reaction in a fast setting brushite forming calcium phosphate cement. It was found that the reaction percentage at a given time was dependent on temperature and not powder to liquid (P/L) ratio. Both methods showed that there was, within the temperature range investigated, a single autocatalytic like setting reaction within the cement paste. Final conversion of the reactants was found to be unaffected by temperature and P/L ratio.

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