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J W Nicholson - One of the best experts on this subject based on the ideXlab platform.
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The effect of strontium oxide in Glass–Ionomer cements
Journal of Materials Science: Materials in Medicine, 1999Co-Authors: J W NicholsonAbstract:The reaction of strontium oxide powder with poly(acrylic acid) has been studied both alone and within Glass–Ionomer cements. Reaction was found to be slow and the strontium-carboxylate structure was found to be partially covalent in character, as determined by Fourier transform infrared spectroscopy (FTIR). These are similar to the structures formed by calcium in Glass–Ionomer cements, but are different from typical monomeric strontium carboxylates, which tend to be purely ionic. Strontium oxide powder introduced in two types of Glass–Ionomer cements, slowed down the setting reaction at both 21 °C and 37 °C, but at low levels (5 wt %), increased the compressive strength in both cement formulations studied. However, at higher levels, it was found to decrease the compressive strength. This study confirms the view that strontium is a cement-forming ion; but concludes that, except at very low levels, strontium oxide powder does not improve the properties of Glass–Ionomer cements.
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The effect of strontium oxide in Glass-Ionomer cements.
Journal of Materials Science: Materials in Medicine, 1999Co-Authors: J W NicholsonAbstract:The reaction of strontium oxide powder with poly(acrylic acid) has been studied both alone and within Glass–Ionomer cements. Reaction was found to be slow and the strontium-carboxylate structure was found to be partially covalent in character, as determined by Fourier transform infrared spectroscopy (FTIR). These are similar to the structures formed by calcium in Glass–Ionomer cements, but are different from typical monomeric strontium carboxylates, which tend to be purely ionic. Strontium oxide powder introduced in two types of Glass–Ionomer cements, slowed down the setting reaction at both 21 °C and 37 °C, but at low levels (5 wt %), increased the compressive strength in both cement formulations studied. However, at higher levels, it was found to decrease the compressive strength. This study confirms the view that strontium is a cement-forming ion; but concludes that, except at very low levels, strontium oxide powder does not improve the properties of Glass–Ionomer cements.
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Glass-Ionomer cements in restorative dentistry.
Quintessence international (Berlin Germany : 1985), 1997Co-Authors: J W Nicholson, Theodore P CrollAbstract:This article reviews the current status and future prospects for Glass-Ionomer materials. These materials are of two chemical types: the older, self-hardening cements, which set by an acid-base neutralization reaction to give relatively brittle materials; and the newer, resin-modified cements, which set partly by polymerization and partly by neutralization. Compared with the self-hardening cements, the latter materials have improved esthetics, improved resistance to moisture, and greater toughness. Both types of Glass-Ionomer cement bond well to enamel and dentin and release a clinically useful amount of fluoride. They have been used in a variety of applications: as liners or bases, for luting of stainless steel crowns, for Class V restorations in permanent teeth, and for Class II and Class III restorations in primary teeth. The resin-modified Glass-Ionomers are particularly promising for these latter uses, although it is too early to be sure whether their long-term durability is sufficient. Self-hardening Glass-Ionomer materials are likely to retain specific niches of clinical application, including in their metal-reinforced and cermet-containing forms.
Theodore P Croll - One of the best experts on this subject based on the ideXlab platform.
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Glass Ionomer restorative cement systems an update
Pediatric Dentistry, 2015Co-Authors: Joel Berg, Theodore P CrollAbstract:: Glass Ionomer cements have been used in pediatric restorative dentistry for more than two decades. Their usefulness in clinical dentistry is preferential to other materials because of fluoride release from the Glass component, biocompatibility, chemical adhesion to dentin and enamel, coefficient of thermal expansion similar to that of tooth structure, and versatility. The purpose of this paper was to review the uses of Glass Ionomer materials in pediatric dentistry, specifically as pit and fissure sealants, dentin and enamel replacement repair materials, and luting cements, and for use in Glass Ionomer/resin-based composite stratification tooth restoration (the sandwich technique). This article can also be used as a guide to research and clinical references regarding specific aspects of the Glass Ionomer systems and how they are used for young patients.
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Glass-Ionomer cements in restorative dentistry.
Quintessence international (Berlin Germany : 1985), 1997Co-Authors: J W Nicholson, Theodore P CrollAbstract:This article reviews the current status and future prospects for Glass-Ionomer materials. These materials are of two chemical types: the older, self-hardening cements, which set by an acid-base neutralization reaction to give relatively brittle materials; and the newer, resin-modified cements, which set partly by polymerization and partly by neutralization. Compared with the self-hardening cements, the latter materials have improved esthetics, improved resistance to moisture, and greater toughness. Both types of Glass-Ionomer cement bond well to enamel and dentin and release a clinically useful amount of fluoride. They have been used in a variety of applications: as liners or bases, for luting of stainless steel crowns, for Class V restorations in permanent teeth, and for Class II and Class III restorations in primary teeth. The resin-modified Glass-Ionomers are particularly promising for these latter uses, although it is too early to be sure whether their long-term durability is sufficient. Self-hardening Glass-Ionomer materials are likely to retain specific niches of clinical application, including in their metal-reinforced and cermet-containing forms.
John W Nicholson - One of the best experts on this subject based on the ideXlab platform.
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fluoride release and uptake in enhanced bioactivity Glass Ionomer cement Glass carbomer compared with conventional and resin modified Glass Ionomer cements
Journal of Applied Oral Science, 2019Co-Authors: Ammar M H R Hasan, S. K. Sidhu, John W NicholsonAbstract:Objectives To study the fluoride uptake and release properties of Glass carbomer dental cements and compare them with those of conventional and resin-modified Glass Ionomers. Materials and methods Three materials were used, as follows: Glass carbomer (Glass Fill), conventional Glass Ionomer (Chemfil Rock) and resin-modified Glass Ionomer (Fuji II LC). For all materials, specimens (sets of six) were matured at room temperature for time intervals of 10 minutes, 1 hour and 6 weeks, then exposed to either deionized water or sodium fluoride solution (1000 ppm in fluoride) for 24 hours. Following this, all specimens were placed in deionized water for additional 24 hours and fluoride release was measured. Results Storage in water led to increase in mass in all cases due to water uptake, with uptake varying with maturing time and material type. Storage in aqueous NaF led to variable results. Glass carbomer showed mass losses at all maturing times, whereas the conventional Glass Ionomer gained mass for some maturing times, and the resin-modified Glass Ionomer gained mass for all maturing times. All materials released fluoride into deionized water, with Glass carbomer showing the highest release. For both types of Glass Ionomer, uptake of fluoride led to enhanced fluoride release into deionized water. In contrast, uptake by Glass carbomer did not lead to increased fluoride release, although it was substantially higher than the uptake by both types of Glass Ionomer. Conclusions Glass carbomer resembles Glass Ionomer cements in its fluoride uptake behavior but differs when considering that its fluoride uptake does not lead to increased fluoride release.
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Resin-modified Glass-Ionomer cements
Materials for the Direct Restoration of Teeth, 2016Co-Authors: John W Nicholson, Beata CzarneckaAbstract:This chapter describes resin-modified Glass-Ionomer cements, which were introduced into the dental profession in 1991. In addition to the components of conventional Glass-Ionomers, resin-modified Glass-Ionomer cements contain a monomer system, usually 2-hydroxyethyl methacrylate (HEMA) plus initiator. Cure is brought about by the joint effect of an acid–base reaction and an addition polymerization, the latter typically being promoted by the action of visible light. Mechanical properties of resin-modified Glass-Ionomers are similar to those of conventional Glass-Ionomers, and they also show the properties of adhesion and fluoride release. However, as a consequence of their HEMA content and its release, their biocompatibility is somewhat compromised.
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Modern Glass-Ionomer materials of enhanced properties
Materials for the Direct Restoration of Teeth, 2016Co-Authors: John W Nicholson, Beata CzarneckaAbstract:This chapter reviews two types of Glass-Ionomer materials that have been formulated to possess enhanced bioactivity compared with either conventional Glass-Ionomer cements or resin-modified Glass-Ionomer cements. The Glass carbomer is based on similar chemistry to conventional Glass-Ionomers, with the addition of bioactive filler and silicone oil, the latter to reduce brittleness. The Activa brands are of the resin-modified type, with a novel resin system. They are substantially polymer-based but seem to contain sufficient acid–base components to allow them to set to an extent away from light. Both types of materials have been developed only recently, so experience in using them is limited. Preliminary findings on their properties and clinical uses are reported.
Beata Czarnecka - One of the best experts on this subject based on the ideXlab platform.
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Resin-modified Glass-Ionomer cements
Materials for the Direct Restoration of Teeth, 2016Co-Authors: John W Nicholson, Beata CzarneckaAbstract:This chapter describes resin-modified Glass-Ionomer cements, which were introduced into the dental profession in 1991. In addition to the components of conventional Glass-Ionomers, resin-modified Glass-Ionomer cements contain a monomer system, usually 2-hydroxyethyl methacrylate (HEMA) plus initiator. Cure is brought about by the joint effect of an acid–base reaction and an addition polymerization, the latter typically being promoted by the action of visible light. Mechanical properties of resin-modified Glass-Ionomers are similar to those of conventional Glass-Ionomers, and they also show the properties of adhesion and fluoride release. However, as a consequence of their HEMA content and its release, their biocompatibility is somewhat compromised.
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Modern Glass-Ionomer materials of enhanced properties
Materials for the Direct Restoration of Teeth, 2016Co-Authors: John W Nicholson, Beata CzarneckaAbstract:This chapter reviews two types of Glass-Ionomer materials that have been formulated to possess enhanced bioactivity compared with either conventional Glass-Ionomer cements or resin-modified Glass-Ionomer cements. The Glass carbomer is based on similar chemistry to conventional Glass-Ionomers, with the addition of bioactive filler and silicone oil, the latter to reduce brittleness. The Activa brands are of the resin-modified type, with a novel resin system. They are substantially polymer-based but seem to contain sufficient acid–base components to allow them to set to an extent away from light. Both types of materials have been developed only recently, so experience in using them is limited. Preliminary findings on their properties and clinical uses are reported.
Joe J. Simmons - One of the best experts on this subject based on the ideXlab platform.
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Silver-alloy powder and Glass Ionomer cement.
Journal of the American Dental Association, 1990Co-Authors: Joe J. SimmonsAbstract:This article examines some physical property improvements made when a spherical silver alloy powder is added to a hydrous, restorative (type II) Glass Ionomer cement. When this first metal-reinforced Glass Ionomer cement is handmixed thickly and quickly, physical properties and clinical handling are improved. These various improvements make this metal-reinforced cement similar in clinical applications to a biocompatible dental epoxy. Three clinical cases are illustrated to show how simply this metal-reinforced Glass Ionomer cement can be used in dental practices.
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Silver–Alloy Powder and Glass Ionomer Cement
Journal of the American Dental Association, 1990Co-Authors: Joe J. SimmonsAbstract:This article examines some physical property improvements made when a spherical silver alloy powder is added to a hydrous, restorative (type II) Glass Ionomer cement. When this first metal-reinforced Glass Ionomer cement is handmixed thickly and quickly, physical properties and clinical handling are improved. These various improvements make this metal-reinforced cement similar in clinical applications to a biocompatible dental epoxy. Three clinical cases are illustrated to show how simply this metal-reinforced Glass Ionomer cement can be used in dental practices.