Fluoride release from two types of fluoride-containing orthodontic adhesives: Conventional versus resin-modified glass ionomer cements—An in vitro study

ABSTRACTBackground: Restoring carious teeth is one of the major treatment needs of young children. Glass ionomer cement (GIC) systems had become the most important dental restorative and luting materials for use in preschoolers, children and teenagers. Several attempts in developing GIC with antibacterial effects by addition of bactericides, such as chlorhexidine, have been reported.Aim: Aim of the study was to evaluate and compare the color and fluoride ion release of conventional and resin-modified GICs in combination with 1.25 and 2.5% chlorhexidine diacetate.Materials and methods: The control groups consisted of conventional GIC and resin-modified GIC. The experimental groups consisted of conventional and resin-modified GIC groups, consisting of 1.25 and 2.5% chlorhexidine. A total of six groups were included with each group being allotted 20 specimens for the evaluation of color stability and 10 specimens each were allotted for the evaluation of fluoride release.Color and fluoride release were recorded using spectrophoto-meter and fluoride selective electrode respectively at 24 hours 7 days and 1 month.Results: Resin-modified GIC groups showed less color stability and better fluoride release at the end of the study compared to conventional GIC groups.Conclusion: There was no significant change in color and fluoride release between 1.25 and 2.5% conventional GIC and also between 1.25 and 2.5% resin-modified GIC combined with chlorhexidine diacetate at the end of the study. Conventional GIC showed better color stability and less fluoride release compared to resin-modified GIC.How to cite this article: Prabhakar AR, Pattanshetti K, Sugandhan S. A Comparative Study of Color Stability and Fluoride Release from Glass Ionomer Cements Combined with Chlorhexidine. Int J Clin Pediatr Dent 2013;6(1):26-29.

New acid-resistant glass ionomer cements (GIC) claim to be able to withstand acidic conditions while also protecting surrounding tooth structures and preserving function. Currently, there are only a few studies that assessed mechanical properties, ion release, and changes that occur around an acid-resistant GIC-dentine bonded interface under acidic conditions. This study aims to investigate the mechanical properties and fluoride release of GIC and the dentine hardness changes of the tooth that occur near the GIC-dentine bonded interface under invitro conditions simulating carious and erosive challenges. A total of 96 beam-shaped specimens (2 mm × 2 mm × 25 mm) were prepared from two types of GIC and placed in neutral pH, carious, and erosive conditions for a total of 3 days over 2 time points to determine the flexural strength change and fluoride release. Twenty-four bovine teeth specimens with a 3 mm × 2 mm diameter cavity restored by two GICs (Fuji BULK (acid-resistant GIC)), Fuji IX Extra (conventional GIC) were subjected to carious (pH 4.4) and erosive (pH 2.3) conditions for 8 and 10 days, respectively. Hardness tests of the dentin surrounding the restorative material were conducted on the surface and cross-sectional interface. Data was tested for significant differences (α = 0.05) utilizing three-way analysis of variance with a Bonferroni post hoc test for multiple comparisons. No significant differences were observed in all comparisons of flexural strength between acid-resistant (~32 MPa) and conventional GICs (~26 MPa). Significant differences were observed in the fluoride release (p < 0.05) between different acidic environments for the same material, between different time points for the same material, and between different materials for day 1 in all conditions. The largest difference in fluoride release between conventional and acid-resistant GIC occurred on day 1 in the control groups, where the fluoride release was 63.1 and 28.2 ppm, respectively. This difference dropped substantially by day 3, where the ppm for conventional and acid-resistant GIC measured 11.9 and 3.9 ppm, respectively. Under carious and erosive conditions, both conventional and acid-resistant GIC showed higher fluoride releases, with erosive conditions showing sustained high fluoride releases of 60.1 and 55.2 ppm, respectively. Overall percent mass for the erosive condition from day 1 to day 3 decreased by 55.5% and 47.1% for conventional and acid-resistant GIC, respectively. A significant difference in dentine hardness (p < 0.001) was observed under erosive treatment between conventional and acid-resistant GIC at both the surface (0.27 GPa vs. 0.36 GPa) and cross-sectional (0.24 GPa vs. 0.32 GPa) sites, respectively. A significant difference in hardness (p < 0.001) was observed for acid-resistant and conventional GIC between all conditions, except between carious and erosive for the acid-resistant GIC. In conclusion, acid-resistant GIC was more resistant to demineralization on regions surrounding the restored cavity under erosive conditions compared to conventional GIC. There were no significant differences in flexural strength observed between acid-resistant and conventional GIC for all conditions, while initial fluoride release for conventional GIC was found to be slightly higher compared to the acid-resistant GIC.

Objective To evaluate the compressive strength and fluoride ion release of conventional and resin-modified glass ionomer cement mixing methods (hand mix and mechanical mix) compared to ready-to-use ones. Materials and Methods Two conventional glass ionomer cements (GICs) (Fuji II and Fuji II Caps), two resin-modified GICs (Fuji II LC and Fuji II L Caps), and one ready-to-use GIC (Ionoseal, Voco) were used. For the compressive strength test, cylindrical specimens (6 mm × 4 mm) of each group were prepared. The test was performed in a universal testing machine (EMIC DL2000). For the fluoride release test, specimens were prepared in the form of discs and placed in deionized/distilled water, which were replaced daily for 15 days. The fluoride ion release readings were performed on an electrode (Orion 96-09) connected to a digital ion analyzer (Quimis 0400ISE). The compressive strength data were analyzed with one-way ANOVA, and the ion release data were submitted to repeated measures ANOVA (material vs. time) and Holm–Sidak post test (α = 5%). Results The one-way ANOVA showed statistical difference between the tested materials (p < 0.001). Ionoseal showed the highest values of compressive strength (p < 0.001). Mechanical manipulation increased the compressive strength only for conventional GIC, and resin-modified GIC did not present any statistical difference. Conventional GIC (mechanical mix) showed higher fluoride release on first day than the other groups tested. Conclusion There was influence of the mixing methods of the materials on the compressive strength and fluoride release pattern of the glass ionomer cements.

In vitro comparison of orthodontic band cements

ObjectivesTo 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 MethodsThree 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.ResultsStorage 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.ConclusionsGlass 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.

In this investigation, the in vitro sustained fluoride release, weight loss and erosive wear of three conventional glass ionomer cements (Fuji IX, ChemFil Superior, Ketac-Silver), three resin-modified glass ionomer cements (Fuji II LC, Vitremer, Photac-Fil), a polyacid-modified resin composite (Dyract), and a resin composite control material (Z100) were compared. The amounts of fluoride released and weight changes were measured for 12 weeks using a fluoride electrode with TISAB III buffer. After 12 weeks, the specimens were recharged with fluoride using 2 mL of 1.23% APF gel. The recharged specimens were assessed for the amounts of fluoride released and weight changes over another 12 weeks. At the end of the experiment, the specimens were examined with SEM and surface profilometry. All materials, with the exception of Z100, showed the highest initial fluoride release rates during the first 2 days, dropping quickly over 2 weeks and becoming largely stabilised after 5 weeks, in an exponential mode. The recharging of the specimens with APF gel caused a large increase in the amounts of fluoride released during the first 2 days only. Analyses for all cements showed strong correlations between mean weight loss and cumulative fluoride release over a 5-week period following the application of the APF gel. SEM and surface profilometry found that roughness increased from the polyacid-modified resin composite to the conventional glass ionomer cements. APF gel caused erosive wear of the glass ionomer cements especially, and the wear correlated well with the weight losses. To minimise surface erosion, APF gel should not be used on these cements, especially as the recharging effects are transitory.

The anticaries potential of restorative ionomeric materials should be evaluated under a pH-cycling regime that simulates the caries process of demineralization and remineralization. Ten glass ionomer cement (GIC) materials and five resin-modified glass ionomer cement (RMGIC) materials were evaluated. A resin composite was used as a negative control. Six discs of each material were immersed for 6 and 18 hours each day in demineralizing (De-) and remineralizing (Re-) solutions, respectively. The solutions were changed daily over 12 days, during which the fluoride concentration was determined using an ion-specific electrode. The results were expressed as (1) the daily fluoride concentration in the Deand Re- solutions (μg F/ml), (2) the amount of fluoride released daily in the De- + Re- solution per area of specimens (μg F/cm2/day), and (3) the cumulative release over the 12-day period (μg F/cm2). During the first days, all materials showed a surge in fluoride release, followed by a gradual decline; however, three distinct patterns were observed, specifically: (1) greater fluoride release in the De- solution compared to the Resolution during the study period; (2) an initial higher release in De- solution; and (3) a similar release in both solutions over the whole period. The materials differed statistically (p<0.05) with respect to daily and cumulative fluoride release. One GIC (Maxxion R) and one RMGIC (Resiglass R) had the highest and lowest ability to release fluoride, respectively. In conclusion, the GICs and RMGICs evaluated exhibited distinct qualitative and quantitative patterns of fluoride release under conditions simulating the caries process, which might reflect their anticaries potential.

Purpose Fluorides are probably the most commonly used anticaries agents. Due to this property they are incorporated into various restorative materials. The rate and amount of fluoride release, however, vary for different materials, which in turn determines the effectiveness of the restorative material in preventing demineralization around the restoration. To evaluate the fluoride release and area of demineralization of resin modified glass ionomers and compomers, and compare them with conventional glass ionomer cement and also to evaluate the relationship between the fluoride release and demineralization. Materials and methods A total of 32 human incisors were chosen and sectioned horizontally at CEJ, and the middle 2 mm of facial enamel isolated and restored with the test materials: Conventional glass ionomer cement (GIC), resin modified glass ionomer cement (RMGIC), compomer and resin composite. The specimens were observed under polarized light microscope with image analyzer to measure the area and depth of demineralization. For fluoride release study, disks of test materials were suspended in deionized water and fluoride release was measured till a period of 4 days. Results The area and depth of demineralization were least around the GIC, followed by RMGIC, compomer and composite (p &lt; 0.05). A negative correlation was found between fluoride release and demineralization which was, however, not statistically significant. Conclusion The 4-day fluoride release was also higher for GIC as compared to RMGIC and Compomer.

Context: Newer glass ionomer cements with improved properties are constantly being developed. One such material is the novel Hybrid Glass-Ionomer cement (HGIC) with properties yet to be studied. Aims: The aim of this study was to compare the flexural strength, shear bond strength, wear resistance and fluoride release of Hybrid Glass Ionomer restorative with Conventional Glass Ionomer Cement (CGIC) and Resin modified Glass Ionomer Cement (RMGIC). Settings and Design: This was an in vitro study. Methods and Material: A total of 300 samples were tested in this study, with 100 samples per group and each group was further subdivided into 5 sub-groups with 20 samples each. Flexural and Shear bond strength values were determined by subjecting the specimens to a universal testing machine. For wear resistance, the specimens were assessed using a pin on the disc tribometer. For fluoride release, the test specimen suspended in 10 mL deionised water was tested at 24 h and 1 week. Statistical Analysis Used: One-way ANOVA. Results: RMGIC had the highest flexural and shear bond strength values followed by HGIC and CGIC. HGIC had the least wear rate followed by RMGIC and CGIC. At 24 h and 1 week, HGIC had the highest fluoride release among the study groups. Conclusions: HGIC exhibited the highest wear resistance and fluoride release among the cements studied. However, flexural and Shear bond strength values, of RMGIC, was comparatively higher.

AimThis in vitro study aimed to evaluate and compare the effect of a protective coating (G-Coat Plus) on the fluoride release of conventional and resin-modified glass ionomer cements (GIC and RMGIC) in primary molarsMethodsA total of 120 extracted primary molars were randomly divided into four subgroups (n = 30) based on the restorative material and application of protective coating: group A—conventional GIC without G-Coat Plus; group B—conventional GIC with G-Coat Plus; group C—RMGIC without G-Coat Plus; and group D—RMGIC with G-Coat Plus. Fluoride release was measured at 1, 2, 3, 4, 5, 6, 7, 14, and 21 days using a fluoride ion-selective electrode and a digital ion analyzer.ResultsConventional GIC with G-Coat Plus showed a significant reduction in the initial burst and mean fluoride release up to day 7, comparable release at day 14, and significantly higher release on day 21 compared to conventional GIC without coating. RMGIC with G-Coat Plus demonstrated significantly reduced fluoride release at all time intervals (days 1–7, 14, and 21) compared to RMGIC without coating. Overall, uncoated GIC and RMGIC exhibited significantly higher fluoride release at all measured intervals.ConclusionThe study concluded that the application of a protective coating (G-Coat Plus) did not completely inhibit fluoride release from GICs. Instead, it significantly reduced the initial burst and resulted in a gradual decline in fluoride release up to the 21st day.How to cite this articleArthilakshmi CU, Vishnurekha C, Baghkomeh PN, et al. Influence of Nano-filled Surface Coating on Fluoride Release Patterns of Conventional Glass Ionomer Cements and Resin-modified Glass Ionomer Cements. Int J Clin Pediatr Dent 2025;18(11):1305–1310.

New-generation glass-ionomer cements contain resin to improve their restorative properties. These resin-modified glass-ionomer cements vary considerably in their chemistry, which could result in corresponding variability in their physical and biological properties. This study investigated the cytotoxicity and the fluoride release of two resin-modified glass ionomers, a conventional glass-ionomer cement, and a resin composite. Samples were prepared and extracted in distilled water for 1, 4, and 7 days; eluates were filtered and tested by means of 3T3 mouse fibroblasts. Cytotoxicity (MTT assay) values were low for all materials and extraction times, indicating minimal cytotoxicity of all materials (less than 30% inhibition). Cytotoxicity of one resin-modified glass ionomer was significantly higher than for the other materials (p < 0.001). One resin-modified glass ionomer and the conventional glass-ionomer cement released significantly more fluoride at each time interval (p < 0.001) than the other resin-modified glass-ionomer cement and the resin composite. Fluoride release and cytotoxicity were correlated (r2 = 0.60; p < 0.001), although the fluoride release does not account for the cytotoxicity observed. Cytotoxicity and fluoride release suggest that one hybrid behaved more like a conventional glass ionomer, and the other like a resin composite. These differences may have implications for material selection in specific clinical situations.

Objective: To compare the fluoride release from Conventional Glass Ionomer Cement (GIC), Resin Modified GIC (RMGIC), and Cention N Alkasite Material. Material and Methods: Forty- five disc-shaped specimens of three different restorative materials (Conventional GIC, RMGIC, and Alkasite material) were made and divided into 3 groups (n=15). Fluoride release was evaluated at the end of Day 1, 7, 14, and Day 28 using fluoride ion-selective electrode. Intergroup and Intra-group analysis was done using One-way ANOVA with a Post-hoc test. A p-value of <0.05 was considered statistically significant. Results: Cention showed more fluoride release (in parts per million) than GIC and RMGIC at increased time duration. However, at the end of day 1, there was lesser fluoride release with Cention, as compared with the other groups. Conclusion: The new Alkasite restorative material showed promising results in terms of fluoride release and is better than GIC and RMGIC at increased time duration.

Developing dental materials for the prevention of remineralization or demineralization is important for high-risk caries patients. This study aimed to evaluate the physicochemical and microbiological effects of adding 45S5 bioglass to resin-modified glass ionomer cement (RMGIC). Samples belonged to the following groups: GIC: conventional glass ionomer cement (Vitro Fil), RMGIC: resin-modified GIC (Vitro Fil LC), and RMGIC/45S5: RMGIC with 10% (wt%) of 45S5. Changes in pH and release of fluoride, calcium, and phosphorus ions under acidic (pH4) and neutral (pH7) pH conditions were evaluated. Antibacterial activity was verified based on colony-forming units. Material sorption and solubility were analyzed after bacterial exposure. After 28 days, the bioactivity of the materials was evaluated using scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Analysis of variance, post hoc Scheffe, and Tukey (α=0.05) tests were employed for statistical analysis. RMGIC/45S5 showed higher alkalization activity, calcium release at pH4 and 7, and sorption than GIC and RMGIC (p < .05). Release of phosphorus and fluoride at pH4 and 7 was higher for GIC than that for RMGIC and RMGIC/45S5 (p < .05). RMGIC/45S5 showed higher values than RMGIC (p < .05). However, antibacterial activity did not differ among the groups. Precipitates of calcium and phosphorus were visualized in RMGIC/45S5 samples via SEM/EDS. These results indicate that the RMGIC/45S5 promotes alkalization and increases the release of calcium, phosphorus, and fluoride ions, resulting in precipitate deposition rich in calcium and phosphorus, thereby being a promising option to improve the bioactivity of RMGIC.

BackgroundThis study aimed to compare the effect of chitosan (CH) and hydroxyapatite (HP) on the surface roughness and microhardness of a conventional glass ionomer cement (CGIC) and a resin modified glass ionomer cement (RMGIC). Material and Methods60 disk-shaped specimens (2mm x 6mm) were prepared in 6 groups; group I: CGIC, group II: RMGIC, group III: CGIC + 15% volume CH solution in liquid, group IV: CGIC +10% weight micro-HP in powder, group V: RMGIC + 15% volume CH, group VI: RMGIC + 10% weight micro-HP. After storage in deionized water at room temperature for 24 hours, the surface roughness and microhardness of the specimens were measured using a surface profilometer and Vickers microhardness (VHN) tester, respectively. Data were analyzed using two-way ANOVA, Tukey HSD test and paired t-test (P<0.05). ResultsThe microhardness values of RMGIC and CGIC decreased significantly with the addition of micro-HP (P<0.001). None of the CH-containing GICs showed significant changes in microhardness (P = 0.552). The VHN values of CGIC were higher than RMGIC, regardless of the added substance (P<0.001). The surface roughness (Ra) values (μm) of both RMGIC and CGIC decreased significantly with the addition of CH (P = 0.004). The incorporation of micro-HP into GICs did not have a significant effect on surface roughness values (P = 0.700). The RMGIC showed less Ra values compared to the CGIC regardless of the added substance (P<0.001). The lowest and highest Ra values were observed in RMGIC + CH and CGIC + micro-HP groups, respectively. ConclusionsThe addition of CH to GIC and RMGIC reduced the surface roughness and did not have an adverse effect on the microhardness. Mixing GIC and RMGIC with micro-HP resulted in microhardness reduction and did not affect the surface roughness. Key words:Glass ionomer, hydroxyapatite, chitosan, hardness, surface roughness

In this study, we evaluated the effects of 10 wt% spherical silica filler (SSF) addition on 24-h compressive strength, modulus of elasticity, water uptake, and immediate setting shrinkage of conventional glass-ionomer (Fuji II and Experimental) and resin-modified glass-ionomer (Fuji II LC EM) cements. The glass-ionomer cement powders were modified by being mixed with 10 wt% SSFs with an average particle diameter of 0.3 μm. The materials were mixed to consistencies similar to the flow of Fuji II mixed with a powder-liquid ratio of 2.7∶1 (w/w). The 24-h compressive strength, modulus of elasticity, water uptake, and immediate setting shrinkage were observed and the results compared with the original materials mixed with similar flow. The addition of SSF increased the compressive strength value to 1.1 times, while the increase of moduli of elasticity was 1.10 to 1.35 times. In general, the addition of SSF decreased the 24-h water uptake to 80–90% and reduced the immediate setting shrinkage to 70–79% of the original materials. The addition of 10 wt% SSF improved the characteristics of conventional and resin-modified glass-ionomer cement.