Glass-ionomers are shown to set by an acid-base reaction within 2-3 min and to form hard, reasonably strong materials with acceptable appearance. Where a single brand is available as both a hand-mixed and capsulated version, the two types, of cement have to be formulated differently. As expected for a composite material, they show the, same trends as compressive strength, typically improving at higher powder:liquid ratios and high, Fluoride release is considered one of the important advantages of glass-ionomer cements [, It can be sustained for very long periods of time [, ], and shows a pattern of an initial rapid release, (“early burst”), followed by a sustained, lower level diffusion-based release [, follow the pattern described by the equation [, is the cumulative fluoride release at time, is the time taken for fluoride release to drop by a half, the so-called. acrylic/maleic acid copolymer are less satisfactory in service. Several roles, ]. Bond strengths develop quickly, with about 80% of the final bond strength, This is driven by the hydrophilic nature of both the, Adhesion then develops rapidly, due to the, These hydrogen bonds are slowly replaced by t. Collagen does not seem to be involved in the bonding at all [50]. Made of a silicate glass powder combined with a water-soluble polymer, these cements are also called \"giomers.\" They are used to permanently cement dental inlays, bridges, crowns and orthodontic brackets and to fill cavities. Aluminium has been shown to, occur in both 4- and 5-co-ordination in various glasses [, on the co-ordination state of aluminium [, The substitution of calcium with strontium in glasses of this type can be achieved by using the, has the effect of increasing radiopacity compared with calcium in these glasses without any adverse, effect on the appearance of these cements. In terms of weight changes, there was a moderate increase in the mass during the entire experimental period. Resin-modified glass-ionomers have the same clinical applications as conventional, ], though they are not recommended for the ART technique because. The antimicrobial activity of T1107SB-modified GIC (T-GIC) was studied by the "cut plug method" and minimal inhibitory concentration (MIC) test. The best of both worlds These restorative materials are cements created by mixing an acid (usually a polyalkenoic acid) and a base (glass powder) to form a salt – the resulting glass ionomer. reactions, one involving the glass plus polyacid, the other hydroxyapatite plus polyacid. Characterization of T1107SB was carried out by Fourier transform infra-red spectroscopy (FTIR), Elemental micro-analysis and Thermal gravimetric analysis (TGA). For maximum translucency the glass needs to be clear and its refractive index close to that of the cement matrix. Experimental results showed that spatial contrast and speckle grain size increased as two studied cements underwent their setting reactions. ; Wilson, A.D. Glass ionomer cement formulations. UTS and µKHN data were submitted to one-way ANOVA, followed by Tukey’s test (α= 5%). As aluminium carries a formal 3+ charge, it does not counteract the effect of the. Join ResearchGate to find the people and research you need to help your work. The occlusal dentin surfaces of six teeth were ground flat. The proportion of tightly-bound water increases with time for the first month. Adhesion to dentin and physical properties of a light-cured glass-ionomer liner/base. Both types of cement took up water with net uptake varying with the storage solution. Results ; Peters, M.C.R.B. Delayed demineralization of adjacent sound teeth and remineralization of demineralized underlying dentin are caused by the restorative material that releases fluoride. and of these (+)-tartaric acid was the more effective. Glassoionomer cements are being marketed as dental materials since the Seventies. Composite resin fillings are the most common alternative to dental amalgam. The working and setting time (WT and ST) of cements was measured by a modified Wilson's rheometer. Care is needed therefore in making generalisations about the properties, because their performance is satisfactory even if they have not been properly mixed, or allowed to, The current ISO standard for glass-ionomers [, ] gives minimum values for certain physical, allowed onto the market, rather than typical for materials known to perform well clinically, The only type of strength that the ISO standard deals with is compressive str, glass-ionomers also have reasonable flexural strength [, ] have also been determined. substitution on esthetics, radiopacity and fluoride release. Finally, two main phases were distinguished in the hardening process, as reported in the literature; however, the technique we propose has the advantage of easily identifying these two phases. All hvGIC and ghRS restorations showed significantly higher abrasive wear than CR (p < .001), while the conventional GIC displayed a significant underperformance compared with any other material (p < .001). High biocompatibility. Also use high powder:liquid ratio (3:1 to 4:1). The physical properties of glass-ionomer cements are influenced by how the cement is prepar, including its powder:liquid ratio, the concentration of the polyacid, the particle size of the glass powder, and the age of the specimens. It is also a requirement that the bone adhesive shows biocompatibility under physiological conditions, with minimal or no cytotoxicity [16]. n be seen using scanning electron microscopy. behaviour of glass-ionomer dental cements. Compressive strength is not a fundamental property of materials, because compression, causes a specimen to fracture in complex ways in directions approximately at right angles to the, material continues to undergo slow changes over time. Strength typically increases, as does translucency, proportion of tightly-bound water within the structure increases. Bluefield Centre for Biomaterials, London, Adult Oral Health, Institute of Dentistry, Dental Physical Sciences, Institute of Dentistry, The Bluefield Centre for Biomaterials, London EC1N 8JY, Correspondence: john.nicholson@bluefieldcentre.co.uk; Tel. 2. typically 2-hydroxyethyl methacrylate, HEMA, (Figure, Resin-modified glass-ionomers set by the twin processes of neutralization (acid-base reaction) and, addition polymerization, and the resulting material has a complicated structure based on the combined, reactions means that there is a sensitive balance between them [, may jeopardize the reliability of the set material, and as a consequence, close adherence to the, manufacturer’s recommendations on the duration of the irradiation step is essential in order to, essential components as conventional glass. Dispensing and Composition of Glass Ionomer Cement The aim of this study is to resume characteristics and indications of glassionomer cements and to evaluate their clinical efficacy in restorative dentistry. In acidic conditions, these ions are released in larger quantities than in, neutral conditions. Glass carbomers contain high proportions of glass compared with conventional glass-ionomers, Studies of the setting reaction suggest that the setting of glass carbomer involves two parallel. They can be classified into three types, depending on the intended, For anterior repairs where appearance matters, T, For use where appearance is not important (posterior restoration or repairs), T, Higher powder:liquid ratio for bases (3:1 to 6.8:1), where the base acts as a dentine substitute in. CS and E were investigated in a universal testing machine according to the ISO 9917:2007. Extracts were prepared from two commercial glass-ionomers (Fuji IX and ChemFlex) under both neutral and acidic conditions. Clinical Significance relatively low in freshly prepared specimens, but incr, this is that the quoted values in the literature are not the true measures of the adhesive bond str, Adhesion is important because it aids the retention of glass-ionomer cements within the tooth, and also reduces or eliminates marginal leakage. see all. The improvement of GICs properties in dentistry applications can be achieved by adding bioactive materials like HA micro and nanoparticles. It is the diluted version of the RMGI cement, Fuji II LC. 8. The plant extracts (PEs) enhanced the antimicrobial activity against S. mutans and also against M. luteus in the higher concentration while compressive strength was improved by addition of the PE at higher concentrations. Fluoride release is enhanced from these cements, though, Several possible compounds have been studied as rate-modifying additives at either 5% or 10%, ]. This mixes the cement after which the freshly-formed paste is extruded from the. across the glass-ionomer cement surface. , 2nd ed. Glass–ionomer cements (GICs), frequently also referred to as glass polyalkenoate cements, are restorative materials that consist of a powder and a liquid which are mixed to produce a plastic mass that subsequently sets to a rigid solid. The rate at which these cements will set is largely controlled by the Al//2O//3/SiO//2 ratio of the glass. Condition. The dimensional stability allows the cement to, retain its marginal adaptation and seal with the tooth. Hence, most of calcium ions lie well inside the particles, A silicone oil comprising a polydimethylsiloxane generally of linear structure, which contains, hydroxyl groups. Operative Dentistry: Mixing Glass Ionomer Cement Page 2 of 2 mark, light cure for an additional 30 seconds. Bioactive glasses have found applications in fields such as orthopedics and dentistry, where they have been utilized for the restoration of bone and teeth. ; Fernandez, C. Stray-field imaging and. This allows the silicone oil to form hydrogen bonds with other components of. ; Coleman, N.J.; Booth, S.E. resin-based fissure sealants on permanent teeth: A meta analysis. Clinical evaluations of resin-modified glass-ionomer restorations. research, the ceramic part of GIC was prepared using melting method, and micro and nano-hydroxyapatite were synthesized from natural bone. ; Nicholson, J.W. Releases fluoride. Featherstone, J.D. Glass Ionomer is a Solid state NMR spectroscopy, has shown that this filler is actually hydroxyapatite [, ] and it is included to promote the formation, of enamel-like material at the interface with the tooth, as observed previously with conventional, The glass used in glass carbomer contains strontium, and also high amounts of silicon [, as well as a small amount of calcium. Resinous coating of hvGIC or ghRS does not appear to exert an effective long-term protection against advanced abrasive wear. Alcoholic extract of Salvadora persica, Olea europaea, and Ficus carcia leaves were prepared using a Soxhlet extractor for 12 h. The plant extract mixture (PE) was added in three different proportions to the water used for preparation of the dental cement (Group 1:1 PE, 2:1 PE, and 1:2 PE). However for very low load indentations this assumption cannot be made. The glass ionomer cement contains the powder of the silicate cement and liquid of the polycarboxylate cement. The mean follow-up was 6,9 months, ranging from 2,1 to 17,9 months. First, application of the fresh cement paste allows, proper wetting of the tooth surface to take place. An increase in radiopacity makes it easier for the clinician to identify the presence of recurrent caries under a restoration in a radiograph. The present work outlines the formation of flexible organic-inorganic polyacrylic acid (PAA) – glass hybrids, commercial forms are known as glass ionomer cements (GICs). Both materials were applied with or without their respective resinous coating, and were compared with a conventional GIC (Ketac Fil) and a hybrid composite resin (CR; G-ænial Posterior). It is the diluted version of the RMGI cement, Fuji II LC. The pH of the acid extracts was 4, conditions under which fluoride complexes with protons as HF or HF2 -, it also complexes with aluminium, which was found to be present in higher amounts in the acid extracts. Access scientific knowledge from anywhere. Glass ionomer cements contain organic acids, such as eugenol, and bases, such as zinc oxide, and may include acrylic resins. Resin-Modified Glass Ionomer Filter applied. Thereafter, the cements were removed and the solution was tested for F(-), Sr(2+), Ca(2+), and Al(3+) release. molecular weights increase the strength of the set cement, but solutions of high molecular weight, polymers have high viscosities, making them difficult to mix. X-ray diffraction (XRD) pattern and X-ray photoelectron spectroscopy (XPS) further confirmed the formation of crystalline CuO phases on the surface of the annealed Cu-glass. A study of glass-ionomer cement and its interface with enamel and. The atraumatic restorative tr. The glass ionomer cement has The glass ionomer dental cement is derived from polycarboxylate and silicate cement. Glass ionomer is the only material that has the self-adhering property. light-curable low viscosity monomer. These cements are considered technique-and methodology-sensitive restorative materials. A comparison of the total wear using a fluorescence-aided identification technique (OraCheck) followed, and differences (α = 5%) between groups were compared by means of MANOVA. The former include a monomer and set in part by an addition polymerization, which, augments the acid-base process and can be controlled using light activation. This results in the movement of ions such as Na, ions. Compressive strength results revealed that there was no statistically significant difference between the different mixtures and the control except for the highest tested concentration that showed the highest mean values. Results Zainuddin, N.; Karpukhina, N.; Hill, R.G. The compressive strength (CS), diametral-tensile strength, flexural strength (FS) and flexural modulus (Ef) of cements (n = 20) were measured after storage for 1 day, 1 week and 1 month. In this paper, we monitor the setting reaction of commercial glass ionomer cements using a laser speckle technique and adopting a spatial approach in the analysis of recorded speckle images. A study has been undertaken of the interaction of complexed fluoride extracted from glass-ionomer dental cements with synthetic hydroxyapatite powder. This is because early research studied a range of mono-, di- and tri-carboxylic acid monomers in, polymers for cement formation, including itaconic and tricarballylic acid [, to assume that these substances must be used in practical cements. They are also advised to light-cure any unused remnants of material prior to disposal. CPD/Clinical Relevance: Resin luting materials are appropriate for placement of all indirect restorations: the self-adhesive variants have simplified the use of such materials. Objective Significance Being hydrophilic they can absorb any fluid left at the, bottom of the fissure and still adhere to the enamel. phase, though it has been found to last for up to four weeks. A continuous supply of low levels of fluoride to the dental hard, ] with concentrations at the parts per million level being sufficient, to inhibit dentine demineralization by a measurable amount [. The circle indicates part of the ion-exchange layer. Some structural aspects of glasses used in ionomer cements. For µKHN test a Knoop diamond indenter was used to make five indentations in the upper/light irradiated surface of the specimens. A group of patients was, Glass Ionomer Cements (GICs) are one of the most important dental restorative materials. ; Peters, M.C.R.B. Composite resin fillings are often light cured by a "blue-light" in layers to build up the final restoration. At 7, 14 and 28 days, the final pH values of artificial saliva solutions were measured using a pH electrode meter. This leads to the surface area being increased and allows, Overall, therefore, adhesion of glass-ionomer cements can be attributed to two inter-related, groups on the polyacid molecules and calcium ions in the tooth surface [, observed experimentally on hydroxyapatite [, high vacuum, so requiring that the surfaces must be more strongly desiccated than under, Over the longer term, a diffusion process occurs in which ions from the cement and ions fr, the tooth move into the interfacial zone and create an ion-exchange layer (Figure, can be seen using scanning electron microscopy, glass-ionomer cement, Fuji IX (GC, Tokyo, Japan), and analysis showed that the interfacial zone, contained both strontium and calcium, indicating that this zone results from movement of ions fr, both the cement and the tooth. Poly(vinyl phosphonic acid) has, been studied as a potential cement former [, ], but its practical use is restricted to a single brand, where, it is used in a mixture with poly(acrylic acid) and effectively acts as a setting rate modifier [. Mitra, S.B. polymerization, and the resulting material has a complicated structure b. reactions means that there is a sensitive balance between them [67]. Water uptake in two glass-ionomer cements stored in various aqueous ionic solutions has been studied following a 6-week storage period, and the bound/unbound water ratio has been determined. The proper name for them, according to the International Organization for Standardization, ], but the term “glass-ionomer” (including the hyphen) is, recognised as an acceptable trivial name [, There are three essential ingredients to a glass-ionomer cement, namely polymeric water, acid, basic (ion-leachable) glass, and water [, ]. These results suggest that a system based on a high-viscosity glassionomer cement and an acrylic light-cured coating seems to be a reliable restorative technique in the middle-term. ; Ferner, A.J. ; Law. By comparison with an immature (1 hour old) specimen of each cement, specimens generally showed a distinct increase in bound/unbound water at 6 weeks, though for specimens stored in 0.9 % NaCl, there was an apparent reduction in this ratio, which is attributed to greater dissolution than uptake in this solution. based on the product of reaction of weak polymeric acids with powdered glasses of basic character [, Setting occurs in concentrated solutions in water and the final structure contains a substantial amount. In particular, this reduction has been attribute, to the higher crosslink density that develops within copolymer cements compared with cements based, ]. The setting reaction was studied using Fourier transform infrared spectroscopy (ATR-FTIR). Thus, on the one hand, these GIC materials reveal several advantages like tooth-coloured appearance, opacity/radiopacity, antimicrobial effects, and (slow) fluoride ion release over time [50][51][52][53][54]. Under acidic conditions, glass-ionomers, too, will reduce, the pH of the surrounding storage medium [, The ions released have a variety of biological roles. Use high powder:liquid ratio (at least 3:1, and up to 6.8:1). HV was evaluated by a Digital Microhardness Tester (Zwick/Roell, IDENTEC, ZHVμ-S, West Midlands, England). Opacity against rays is obtained by melting of metals such as barium, strontium, or lantium together with glass particles (similar to cermet) or mixing glass power with dental amalgam alloy or zinc oxide [ 6 , 8 , 9 ]. GICs are acid-based materials widely used in clinical dentistry, ... GICs are materials made of calcium and strontium aluminosilicate glass powder (base) combined with a water-soluble polymer (acid). After this initial hardening, there are further reactions, ]. Glass-ionomers were invented in 1969 and reported by Wilson and Kent in the early 1970s. HA micro and nanoparticles were added to GICS in different weight percents (0, 1, 3, 5 and 7 wt.%). adhesion: The mechanisms at the interface. Despite these concerns, there seem to be no case studies or reports in the literature of adverse reactions, by patients or dental personnel to resin-modified glass-ionomers, though there is some anecdotal. Both vital and non-vital teeth were included in this study, except temporary pre-endodontic restorations and applications of glassionomer cement as pulp protection for sandwich technique. The PGN nanoclay was dispersed in the liquid portion of GIC (HiFi, Advanced Healthcare, Kent, UK) at 1%, 2% and 4% (w/w). Methods Under £30.00. Glass-ionomer cement was bonded to the surfaces either with or without polyalkenoic acid conditioning. The thickness of the glass ionomer should be approximately 0.5 mm. Price. The structural analysis of the glass using Raman suggests the formation of CuO nanocrystals on the surface. use electrically-powered cure lamps. convincing evidence to support this. Interfacial ion-exchange layer formed between tooth surface (above) and glass-ionomer cement (below). of unreacted glass which acts as filler to reinforce the set cement. seem achievable from glass-ionomer cements [, ], but they have not been demonstrated over the, longer term in saliva. Before sharing sensitive information, make sure you're on a federal government site. Fluoride release from glass-ionomers increases in acidic conditions [, termed buffering, and may be clinically beneficial because it may protect the tooth from further tooth. toothache is dealt with by extraction of the affected tooth. with side chains that end in unsaturated vinyl groups. The FTIR results showed a new peak at 1041 cm(-1) which increased in intensity with an increase in the nanoclay content and was related to the Si-O stretching mode in PGN nanoclay. Authorship is limited to those who have contributed substantially to the work article. on the polyacid molecules and calcium ions in the tooth su, experimentally on hydroxyapatite [52] and also on enamel and dent, photoelectron spectroscopy, though experimental conditions for these studies involve high, Over the longer term, a diffusion process occurs in which ions from the cement and ions from, the tooth move into the interfacial zone and create an ion, contained both strontium and calcium, indicating that this zone r. the cement, rather than at the interface. consistent with a reduction in the proportion of –Si–O–Si– groups (as shown by decreases in intensity, ) and increase in peaks due to –Si–OH (silanol) (one at 950 cm. Glass ionomers address the shortcomings of both – and more. Ion release was linear to t(1/2) suggesting that this is a diffusion controlled mechanism rather than dissolution. ionomers to untreated enamel and dentine are good [46]. As a result, the risk of caries developing under. Crisp, S.; Lewis, B.G. This technique removes the smear layer and opens the dentinal tubules, and, also partially demineralizes the tooth surface. known, and research continues on this question. Within the mouth, it is the main counterion in hydroxyapatite, and in solution. On the other hand, cements made from acrylic-maleic acid copolymers show an, increase in compressive strength up to a point, but then there is a decline befor, is reached. porosities in it through which water can still escape. Two of them proved highly successful, namely (+)-tartaric acid and citric acid. The polymers used in glass-ionomer cements are polyalkenoic acids, either homopolymer, poly(acrylic acid) or the 2:1 copolymer of acrylic acid and maleic acid. The .gov means it’s official.Federal government websites often end in .gov or .mil. Kervanto-Seppala, S.; Lavonius, E.; Pietila, I.; caries-preventive effect of two fissure sealing modalities in public health care: A single application of glass. Aging did not reduce the bond strength of the conventional glass-ionomer cement to dentin with or without the use of a polyalkenoic acid conditioner. The polymer influences the properties of the glass-ionomer cement formed from them. Both types of cement took up water with net uptake varying with the storage solution. This breakthrough spawned a series of rapid product developments of glass ionomer cements interface with the tooth, which is responsible for their adhesion. Beech, D.R. typically unreliable or non-existent electrical power supplies, which means that electrically driven, throughout the world. Uses of resin luting materials include the luting of any indirect restoration, but these materials have facilitated the development of the resin-retained bridge and aesthetic ceramic or composite restorations, notwithstanding the fact that they may provide, for the first time, truly adhesive luting of crowns and inlays. Unlike composite resin fillings, glass ionomer cements are self-curing and usually do not need a "blue light" to set (harden). The str. For cementation of crowns, bridges, inlays, onlays and orthodontic appliances. ionomers may also cause problems for dental personnel, e anecdotal evidence of allergies developing in the latter gro, ionomers have the same clinical applications as conventional g, ], though they are not recommended for the ART t, they are used in Class I, Class II and Class III restorations, all. selected among those requiring fillings of any Black's classes. ... Glass ionomer cements (GICs) have been applied in daily dental practice for more than five decades. Low powder:liquid ratio for liners (1.5:1) to allow good adaptation to the cavity walls. The glass filler particles are predominantly calcium aluminosilicate glasses, but certain manufacturers replace some of the calcium with strontium or lanthanum to increase cement radiopacity. This article is an updated review of the published literature on glass-ionomer cements and covers their structure, properties and clinical uses within dentistry, with an emphasis on findings from the last five years or so. A one-way ANOVA and Bonferroni test were used to analyze the data with the significance level established at (p ≤ 0.05). The failures appeared to be of a mixed nature, although aging caused more areas of cohesive than adhesive failure in both groups. Due to the acid-washing process, the glass is fairly unreactive towards poly(acrylic acid) or, adsorbed onto the surface of the glass, and this also interferes with the reaction with polyacid. Water was thus shown to become bound within these cements during a relatively slow process, and a mechanism for this water-binding is proposed. ]. £30.00 to £60.00. Advantages of glass ionomer cements include: Other options for replacement of lost tooth structure is through the use of indirect fillings, for example "caps," which are made from ceramics or precious metals such as gold, and the most durable and costly treatment options. The cement is popular because it adheres to enamel and dentin and has the sa… Microprobe techniques have, therefore, the ability to determine the composition of individual minerals in thin section or even concentration variations within a single grain. It is the solvent for the polymeric acid, it allows the polymer to act, as an acid by promoting proton release, it is the medium in which the setting reaction takes place, and, Incorporation of water with glass-ionomers is associated with increases in the translucency of the, glass-ionomer cement. Fluoride is also taken up by glass-ionomer cements, at least in the early stages of a cement’s, ] and early experiments where release from a, cement stored in water was compared with that from a cement stored in fluoride solution confirmed, fluoride-releasing when treated in this way [, Direct measurement confirms that fluoride is taken up by these cements [, ability was found to be almost completely lost on maturation, so that 1 month old specimens of Ketac, Molar Quick (3M ESPE, St Paul, MN, USA) and Fuji IX Fast (GC, T, ]. In addition, calcium or strontium is also released, ions which occur in relatively, insoluble compounds in neutral solutions. Silicate can become incorporated into hydroxyapatite of the tooth, without adversely affecting the crystal geometry [, ], though whether it can do so with the mineral, phase of teeth under clinical conditions is not clear, many biological uses. (CC-BY) license (http://creativecommons.org/licenses/by/4.0/). For example, in, permanent teeth, after 2–3 years, Class I and Class V restorations had success rates of around 90% [, ART is used for children, who generally accept the treatment r, successful in providing dental care for populations that would otherwise have minimal or non-existent, care, and who would otherwise have had several teeth extracted [, These materials were introduced to the dental profession in 1991 [, same essential components as conventional glass-ionomers (basic glass powder, water. It then sets sharply to give the finished, hardened material that can, be completed within the tooth. The fluoride release from the cements is enhanced where some or all calcium is replaced by strontium. cement (below). Choose from 204 different sets of glass ionomer cement flashcards on Quizlet. Conclusion: It was observed that the hybrid resin-modified ionomers generally have higher cohesive strength than conventional ones, but lower microhardness. release/uptake of fluoride-containing restorative materials. Like some composite resins, glass ionomer cements include a component of glass filler that releases fluoride over time. INTRODUCTIONGlass ionomer cement is a tooth coloured material, introduced by Wilson &Kent in 1972.Material was based on reaction between silicate glass powder & polyacrylicacid.They bond chemically to tooth structure & release fluoride for relatively longperiod. Materials and methods. It releases fluoride, and the literature claims that it has been formulated with the aim, This review was written without external funding, with costs of publication being covered. They release fluoride for considerable, periods of time, a feature which is generally considered to be beneficial, though evidence to support, Modified forms of glass-ionomer are available, in the form of resin-modified glass-ionomers and, glass carbomer. proper wetting of the tooth surface to take place. The objective of the present study is to investigate the reinforcement effect of polymer-grade montmorillonite (PGN nanoclay) on physical properties of glass ionomer cement (GIC). glass ionomer cement Nov 18, 2020 Posted By Robert Ludlum Public Library TEXT ID 72056a63 Online PDF Ebook Epub Library Glass Ionomer Cement INTRODUCTION : #1 Glass Ionomer Cement # Best Book Glass Ionomer Cement # Uploaded By Robert Ludlum, a glass ionomer cement gic is a dental restorative material used in dentistry as a filling material and