Fluoride release from a glass ionomer cement

abstract – The release of fluoride from a glass ionomer cement (ASPA®) was. compared with that from a silicate cement. Test specimens were shaken in a solution with hydroxyapadte for 7 weeks. The solution was changed every week and the fluoride taken up by the hydroxyapatite measured. The specimens released considerably more fluoride during each of the first 2 weeks than during each of the subsequent 5 weeks. The continued release did not decrease very much with time. Slightly more fluoride was released from the glass ionomer cement than from the silicate.     

Fluoride release from a glass ionomer cement.

The release of fluoride from a glass ionomer cement (ASPA) was compared with that from a silicate cement. Test specimens were shaken in a solution with hydroxyapatite for 7 weeks. The solution was changed every week and the fluoride taken up by the hydroxyapatite measured. The specimens released considerably more fluoride during each of the first 2 weeks than during each of the subsequent 5 weeks. The continued release did not decrease very much with time. Slightly more fluoride was released from the glass ionomer cement than from the silicate.     

Long-term F release from glass ionomer cements

Fluoride release from three commercial glass ionomer filling cements and three glass ionomer luting cements was measured in the laboratory over a 12-month period. Fluoride release from these glass ionomer cements was compared with that released from a silicate, silicophosphate, and a fluoride-containing polycarboxylate cement. The fluoride released from the glass ionomer cements throughout the one-year period was similar, both in quantity and pattern, to that released by the silicate cement. The silicophosphate cement tended to release fluoride in somewhat lesser amounts, while the amount of fluoride released by the polycarboxylate was negligible after the first few days. Analysis of these data indicates that these glass ionomer cements probably possess anticariogenic properties similar to those of silicate cement.     

Long-term fluoride release from a glass ionomer cement,a compomer,and from experimental resin composites

The aqueous phase of glass ionomer cements enables fluoride ions to diffuse and to be released from the material. The matrix of resin composites is much less hydrophilic, and fluoride incorporated in the material is only released in small amounts. It was the purpose of the present work to study the influence of resin matrix formulation on the fluoride release from experimental, fluoride-containing resin composites. The resin composites were based on methacrylate monomers and the adduct of maleic anhydride and HEMA (2-hydroxyethyl methacrylate). The resin composites contained 1 w% or 5 w% of AlF3*3H2O. A glass ionomer cement and a compomer were used as controls. Five disks of each material were stored in distilled water at room temperature. By means of a fluoride sensitive electrode, the fluoride release from disk-shaped specimens was determined periodically over 3 years. The glass ionomer cement released the most fluoride (1.54 +/- 4 microg/cm2 after 1 year and 248 +/- 7 microg/cm2 after 3 years). The compomer released relatively little fluoride during the 1st year (30 +/- 1 microg/cm2) but after this time the rate of fluoride release became equal to that of the glass ionomer cement, resulting in a release of 122 +/- 8 microg/cm2 after 3 years. Regarding the resin composites, the fluoride release increased with the hydrophilicity and the acid character of the polymer matrix. The release, however, was significantly lower than that from the glass ionomer cement and the compomer and ranged from 1.2 +/- 0.07 to 42 +/- 3.9 microg/cm2 at 1 year and from 2.3 +/- 0.16 to 79 +/- 6 microg/cm2 at 3 years.     

Fluoride release from three glass ionomers, a compomer, and a composite resin in water, artificial saliva, and lactic acid

The amounts and the pattern of fluoride release from one metal-reinforced glass ionomer cement, two resin-modified glass ionomer cements, one compomer, and one composite resin placed in double-distilled water, artificial saliva, and lactic acid were evaluated in this study. Measurements of fluoride ion release were made for a total of 105 cylindrical specimens (10 mm in diameter and 1.5 mm in height). They were taken over a period of 16 weeks at the intervals of 4, 8, 12, and 24 hours, as well as 2, 3, 7, 14, 28, 56, and 112 days. The pattern of fluoride release was similar for all of the examined materials. The greatest amount of fluoride was released from the metal-reinforced glass ionomer Argion. The resin-modified glass ionomers Vitremer, Fuji II LC; the compomer Dyract; and the composite resin Tetric followed in ranking order. The pH of the environment strongly affected the fluoride release from the materials. There was a significant difference (P < 0.001) in the amounts of fluoride released in lactic acid vs water and artificial saliva, whereas, there was no significant difference (P > 0.05) in the amounts of fluoride released in water vs artificial saliva.     

Fluoride release from glass ionomer cement in vivo and in vitro

The aims of this study were to investigate in vivo the release of fluoride from three glass ionomer cements (GICs) Vitrebond, Ketac-Fil and ChemFil II into the saliva of preschool children for a 1-year period and also to study in vitro the release-absorption-release of fluoride from the same GICs for 16 weeks. In the first part of the study, glass ionomer restorations were placed in primary teeth in preschool children. Unstimulated saliva was collected and the fluoride in the saliva was measured before placement of the restorations, immediately after, after 3 weeks, after 6 weeks, and after 1 year. In the second part of the study, test specimens of GICs were placed in deionized water and the release of fluoride was measured weekly for 16 weeks. At week 12, samples were exposed to fluoride toothpaste. The concentration of fluoride in saliva was 0.04 ppm before placement of the restorations. After three weeks it had increased to 0.8 ppm and the level remained as high as 0.3 ppm even after 1 year. In the laboratory study the tested glass ionomer cements showed a capacity to absorb fluoride from the fluoride toothpaste and then release it. It is concluded that glass ionomer cement can act as a rechargeable slow release fluoride device.     

A comparison of fluoride release from three glass ionomer cements and a polycarboxylate cement

Abstract. This study investigated the fluoride release from three glass ionomer cements, ASPA, ChemFil and ChemBond, and a fluoride-enriched polycarboxylate cement, Poly-F Plus, using a simulated model cavity system. ChemFil released considerably more fluoride than the other materials at all the time intervals investigated. The release from ASPA was greater than that for either ChemBond or Poly-F Plus. Release from ChemFil and ASPA was of a similar order to a silicate cement investigated previously and it is expected that this release should confer some protection against secondary caries.     

Evaluation of a new 2-paste glass ionomer cement

A new 2-paste resin-reinforced glass ionomer cement, Fuji Ortho Band Paste Pak (GC Corporation, Tokyo, Japan), for the placement of orthodontic bands, has been developed for easier handling. The aim of this study was to compare the fluoride release and uptake characteristics of this cement with that of 3 others commonly used to cement orthodontic bands: a conventional resin-reinforced glass ionomer cement, a polyacid-modified composite resin, and a conventional glass ionomer cement. Fluoride release was measured during a 28-day period. After the measurement on day 28, experimental samples were exposed to 1000 ppm sodium fluoride solution for 5 minutes, and fluoride release was then measured for 7 days. Initially, the new 2-paste resin-reinforced glass ionomer cement released the greatest amount of fluoride; the polyacid-modified composite resin released the least initially, and it continued to show the lowest values throughout the study. The fluoride uptake and release values of the new 2-paste resin-reinforced glass ionomer cement were statistically significantly higher than those of the conventional resin-reinforced glass ionomer cement or the conventional glass ionomer cement. The new 2-paste resin-reinforced glass ionomer cement might be a good alternative to conventional products for cementing orthodontic bands.     

Short- and long-term fluoride release from glass ionomers and other fluoride-containing filling materials in vitro

Test specimens of seven different glass ionomer filling materials and one fissure sealant were exposed to running water for 2 yr. One amalgam and one composite, both containing fluoride, were included for comparison. The fluoride release from the specimens was measured periodically after storing the specimens for 24 h or 1 wk in a small amount of water. The fluoride release from the glass ionomers decreased with time and a constant level was reached for most products during the 2-yr period. The release was increased by lowering the pH of the storage solution. The release from the glass ionomers was clearly greater than from the amalgam and the composite.     

Short- and long-term fluoride release from glass ionomers and other fluoride-containing filling materials in vitro

Abstract – Test specimens of seven different glass ionomer filling materials and one fissure sealant were exposed to running water for 2 yr. One amalgam and one composite, both containing fluoride, were included for comparison. The fluoride release from the specimens was measured periodically after storing the specimens for 24 h or 1 wk in a small amount of water. The fluoride release From the glass ionomers decreased with time and a constant level was reached for most products during the 2-yr period. The release was increased by lowering the _pH of the storage solution. The release from the glass ionomers was clearly greater than from the amalgam and the composite.     

Fluoride release from amalgam restorations lined with a silver-reinforced glass ionomer

This study evaluated the amount of fluoride released from amalgam restorations lined with a silver-reinforced glass ionomer. Thirty human extracted molars were divided into three groups of 10 teeth each. Group 1: Class V cavities were made on the facial surfaces and restored with Dispersalloy amalgam. Group 2: Same as Group 1 except 1 mm of GC Lining glass ionomer cement (GIC) was placed on the axial wall before amalgam insertion. Group 3: Same as Group 2 except 1 mm of Miracle Mix silver-reinforced glass ionomer cement (GIC) was placed on the axial wall before amalgam insertion. Before any treatment, all samples were placed in polyethylene vials with 4 ml of deionized water and thermocycled (100x) for baseline fluoride release levels. After restoration, each tooth was replaced in a vial with 4 ml of deionized water. At weekly intervals, each tooth was removed from its aqueous medium and transferred to another vial containing 4 ml of deionized water. Fluoride release was measured four times at weekly intervals with an Orion #9609 fluoride-ion electrode. At 1 and 4 weeks, Miracle Mix released significantly more fluoride than GC Lining (P less than 0.0001).     

An in vitro study of certain properties of a glass ionomer cement.

A glass ionomer cement was tested for its release of fluoride, effect on solubility of enamel, bond to enamel, and ability to seal the cavity. It was comparable to silicate cement in its release of fluoride and its effect on solubility of enamel. The strength of the bond of the cement to tooth structure was similar to polycarboxylate cement, and it appeared to be quite effective in sealing cavities.     

Fluoride recharge of aesthetic dental materials

The objective of the study was to compare the potential for fluoride recharge of two glass-ionomer cements, a resin-modified glass-ionomer cement, a compomer and a fluoride-containing composite in artificial saliva. Disc samples of each of the materials were placed into artificial saliva. The fluoride content of the artificial saliva was determined at various intervals up to 57 days. The discs were subjected to a 2 min exposure of NaF (500 parts/106). This recharge procedure was repeated at 64 and 120 days. The fluoride release was measured before and after recharge. The fluoride release for all of the materials increased after each exposure to NaF; however, the amount for the composite was very low. The resin-modified glass-ionomer cement displayed the greatest potential for fluoride recharge at 57 and 64 days (P<0.05). By 120 days, the amount of fluoride released in the 24 h post-recharge interval had decreased in all the materials. All the materials showed a potential for fluoride recharge. This effect, however, was minimal in the fluoride-containing composite.     

Fluoride release from glass ionomer-lined amalgam restorations

This study evaluated the amount of fluoride released from glass ionomer-lined amalgam restorations. 50 human extracted molars were divided into five groups of 10 teeth each. Group 1: No restorations. Group 2: Class V cavities (2 x 2 x 7 mm) were made on the facial and lingual surfaces and restored with Dispersalloy amalgam. Group 3: Same as Group 2 except 1 mm of Ketac-Bond glass ionomer cement (GIC) was placed on the axial wall before amalgam insertion. Group 4: Same as Group 2 except 1 mm of Chelon-Silver glass ionomer cement (GIC) was placed on the axial wall before amalgam insertion. Group 5: Same as Group 2 except 1 mm of Ketac-Silver GIC was used before amalgam insertion. Before any treatment, all samples were placed in polyethylene vials with 4 ml of deionized water and thermocycled (100x) for baseline fluoride release levels. After restoration, each tooth was placed in a vial with 4 ml of fresh deionized water. At weekly intervals, each tooth was removed from its aqueous medium and transferred to another vial containing 4 ml of deionized water. Fluoride release was measured four times at weekly intervals with an Orion #9609 fluoride-ion electrode. At one week, Ketac-Bond released significantly more fluoride than Ketac-Silver (P less than 0.01) which released significantly more fluoride than Chelon-Silver (P less than 0.01). At four weeks, there was no significant difference in fluoride release between Chelon-Silver and Ketac-Silver, but Ketac-Bond released significantly more fluoride than either of the other materials (P less than 0.01).     

Glass ionomer cements as a fluoride release system in vivo

Fluoride release to saliva from three glass ionomer cements, Vitrabond, Ketac-Fil, and ChemFil II, was followed for six weeks in vivo. Colony forming units (CFU) of S. mutans present in saliva before and after placement of glass ionomer restorations were analysed. Thirty-six children received 1-6 glass ionomer cement restorations of one of the three materials. Unstimulated saliva was collected and analysed before insertion of restorations (baseline measurement), immediately after treatment, after 3 weeks and after 6 weeks. The fluoride concentration was measured according to a method slightly modified from Ekstrand (1977) and Duckworth et al. (1987). Baseline concentration of fluoride was between 0.038 and 0.050 ppm. Immediately after placement of GIC restorations, fluoride concentrations increased to 0.8 for ChemFil II and 1.2 ppm for Ketac-Fil and Vitrabond. After 3 weeks, concentrations of released fluoride decreased about 35% for all three materials, and after 6 weeks, concentrations decreased another 30%. However, still after 6 weeks, the fluoride concentrations of unstimulated saliva was 10 times higher than the baseline values. The more restored teeth surfaces the higher was the saliva fluoride concentration found. The prevalence of S. mutants in saliva decreased after placement of the GIC restorations.     

Fluoride-containing restorative materials

Dental practitioners are exposed to an increasing number of dental materials, which claim the benefits of fluoride release. The purpose of this paper is to critically review the literature of these materials. Glass ionomers, resin modified glass ionomers, compomers, resin composites, fissure sealants and amalgam are discussed. It is clear that a long-term measurable release of fluoride can be observed from certain restorative materials, in vitro, particularly glass ionomer cement, resin modified glass ionomer cement, fluoridated cements, fluoridated dental amalgam and certain fissure sealants. In general, the rate of fluoride release is not constant but exhibits a relatively rapid initial rate, which decreases with time. However, the fluoride release profiles may be dependent on specific formulation and on experimental design and sampling methods. These materials may feature greater longevity, a reduced incidence of marginal failure, an elevated concentration of fluoride in contingent plaque, together with an antibacterial action when compared with non-fluoride releasing materials. In addition, fluoride-releasing materials may perform better in caries inhibition in artificial caries model studies than non-fluoridated materials. While any, or all, of these anti-cariogenic effects may be associated with fluoride release, a direct relationship between fluoride release profiles and such effects has not been determined in vivo.     

Fluoride release from restorative materials and a luting cement

STATEMENT OF PROBLEM: In addition to conventional glass ionomers, a considerable number of different types of materials have been formulated to release fluoride. Variation in composition results in quantitative differences in the amount of fluoride release by these materials. PURPOSE: This study evaluated and compared fluoride release in distilled water from different types of restorative materials and a luting cement. MATERIAL AND METHODS: Fluoride release from 4 glass ionomer formulation restorative materials (Miracle-Mix, Fuji ionomer type III, Fuji II LC improved, and Ketac-Silver), a luting cement (Ketac Cem), a compomer (Compoglass Flow), 2 sealants (Fissurit F, Helioseal F), and a composite resin (Tetric) was evaluated at time intervals of 4, 8, 12, and 24 hours and 2, 3, 7, 14, 28, 56, and 112 days. Seven disks of each material were made and stored for equilibration in double distilled water at 37 degrees C for the time of each measurement. The equilibrated solution was analyzed for fluoride with a TISAB and an ion-specific combination electrode (ORION 960900) connected to an expandable ion analyzer (Crison micropH 2002). Data were analyzed by means of univariate analysis of variance, the Dunnett C post hoc test, and repeated measures analysis. RESULTS: Fluoride was released from all the evaluated materials, with considerable variation in the rate of release but a similar pattern. Among the materials tested, fluoride release from glass ionomer formulations was greater than that from composite resin formulations; the rank of decreasing order was as follows: Miracle Mix > Fuji III, Ketac Cem > Fuji II LC > Ketac Silver, Compoglass F > Fissurit F, Helioseal F > Tetric (> indicates statistical significance; P< .05). CONCLUSION: Under the conditions of this study, glass ionomer formulations and the compomer released more fluoride than the sealants and the composite resin tested.     

Fluoride release from aesthetic dental materials

The objective of the study was to compare the amounts of fluoride released by two glass-ionomer cements, a resin-modified glass-ionomer cement, a compomer and a fluoride-containing composite into deionized water and artificial saliva. Disc samples of each of the materials were fabricated and placed in either water or artificial saliva. Fluoride analysis of the media was performed periodically over 64 days. The data were analysed to show the rate of fluoride release per cm2 per hour for each material. The results showed that the fluoride release rate for all the materials in both solutions decreased dramatically after 24 h. The release rate in artificial saliva was significantly less than in water (P < 0.001). The resin-modified glass-ionomer cement consistently displayed the highest fluoride release rate per hour into both media.     

Effect of one-bottle adhesive systems on the fluoride release of a resin-modified glass ionomer

A dhesive systems associated to resin-modified glass ionomer cements are employed for the achievement of a higher bond strength to dentin. Despite this benefit, other properties should not be damaged. This study aimed at evaluating the short-time fluoride release of a resin-modified glass ionomer cement coated with two one-bottle adhesive systems in a pH cycling system. Four combinations were investigated: G1: Vitremer (V); G2: Vitremer + Primer (VP); G3: Vitremer + Single Bond (VSB) and G4: Vitremer + Prime & Bond 2.1 (VPB). SB is a fluoride-free and PB is a fluoride-containing system. After preparation of the Vitremer specimens, two coats of the selected adhesive system were carefully applied and light-cured. Specimens were immersed in demineralizing solution for 6 hours followed by immersion in remineralizing solution for 18 hours, totalizing the 15-day cycle. All groups released fluoride in a similar pattern, with a greater release in the beginning and decreasing with time. VP showed the greatest fluoride release, followed by V, with no statistical difference. VSB and VPB released less fluoride compared to V and VP, with statistical difference. Regardless the one-bottle adhesive system, application of coating decreased the fluoride release from the resin-modified glass ionomer cements. This suggests that this combination would reduce the beneficial effect of the restorative material to the walls around the restoration.     

Linear regression modeling to compare fluoride release profiles of various restorative materials.

OBJECTIVES: The aim of this study was to compare the released fluoride profiles of various restorative materials by using linear regression analysis. METHODS: Specimens were prepared using a cylindrical Teflon mold with a height of 2 mm and a radius of 8 mm. After being prepared, specimens were immediately placed into artificial saliva which was replaced at various times during 6 weeks. These released intrinsic fluoride amounts were measured by using an ion selective electrode. Then, data obtained cumulatively were statistically analyzed, and the released profiles were compared. RESULTS: It was observed that the materials released fluoride at different levels of concentration and the largest fluoride release was obtained from the conventional glass ionomer cement. This was followed by resin modified glass ionomer cement, polyacid modified composite resin, and fluoride releasing composite resin, respectively. Although the released fluoride amounts of the materials were different, their release profiles were found to be similar in that the release was initially fast and then it became steady as time passed. SIGNIFICANCE: The statistical modeling of the release profiles helps to compare the fluoride release behavior of materials and also to predict fluoride release amounts for the future. In literature, for these purposes, separate nonlinear statistical models have extensively been utilized. However, the single linear statistical modeling approach has numerous advantages such as providing estimators having good statistical properties, exact results, precise inference and simplicity in calculation. Therefore, this study was conducted to introduce the use of single linear regression modeling to compare release profiles statistically.