A dynamic methodology for measuring fluoride release from restorative materials

Evaluation of a new 2-paste glass ionomer cement

INTRODUCTION: The most important property of Fluoride is anti-cariogenic property which aids in remineralization of incipient carious lesions in enamel thereby inhibiting enamel demineralization i.e. it helps in arresting or reversal of incipient enamel lesions. A prolonged exposure of incipient carious lesions to uoride in the aqueous phase achieves the cariostatic effect. OBJECTIVES: The aim of the present study is to evaluate the amount of uoride released by three different Restorative Materialsi.e. Glass Ionomer Cement, Resin Modied Glass Ionomer Cement, Cention on 1st,7th and 15th day followed by Recharge and Re-release after recharging with various Flouride applications. MATERIALS AND METHODOLOGY: Fifteen Disk-shaped specimens for each group (8.5 mm diameter; 3 mm thickness) were prepared from three different restorative materials using cylindrical Teon molds according to manufacturer's instructions. The specimens in each individual group were incubated in a 95% relative humid environment at 37°C for 24 hours. Specimens of each group were immersed in 20 ml deionized water in plastic bottles and stored in the incubator at 37°C, Fluoride concentration was measured using a UV Spectrophotometer after 1st ,7th & 15 days. The samples from each group were now divided into: 3 Sub Groups of ve each. Sub Group A - Control group – No topical uoride application. Sub Group B - The samples were recharged with 2% Neutral Sodium Fluoride solution for 4 minutes and washed with copious deionized water for 10 sec and dried on absorbent paper. Sub Group C - The samples were recharged by hand brushing with a Fluoridated brushing Dentifrice for four minutes and then wiped clean with a tissue and rinsed for 10 sec using copious deionized water and dried. Measurement of uoride Re-release is done by UV Spectrophotometer after 1st ,7th and 15thday after recharge.The results were statistically analysed using analysis of variance (one-way ANOVA) and Tukey Kramer multiple comparison tests (p≤0.05). RESULTS: Independent of the observation time period of thestudy the Conventional GIC released the highest amount of uoride followed by RMGIC & CENTION. The initial burst effect was seen with GIC'S but not with RMGIC, CENTION. After topical uoride application uoride re-release was highest in Sub Group B and GIC had a greater recharging ability followed by RMGIC & CENTION. The uoride re-release was greatest on 1st day followed by rapid return tonear exposure levels. CONCLUSION: From the study it was concluded that, the initialFluoride release was highest from Conventional GIC followedby Resin Modied GIC, CENTION. The Fluoride release was high when recharging with professional regime (2%NaF) as compared to home regime (Toothpaste).

To overcome the drawbacks of glass ionomer cement of sensitivity to initial desiccation and moisture contamination the use of surface coating agent is recommended. The search in this area led to invent of use of nanofillers in surface coating agent, but its effect on fluoride release is not clear. The aim of this study is to evaluate and compare the fluoride release from conventional glass ionomer cement with and without surface coating agent. This in vitro study comprised of total 80 samples (40 samples of each with and without surface coating). Specimens were prepared, G coat plus was applied and light cured. Fluoride release of the sample was measured every 24 h for 7 days and weekly from 7th to 21 st day using Sension4 pH/ISE/MV Meter. Descriptive Statistics, Repeated Measure ANOVA, Paired Sample t-test, Independent Sample t-test, Scheffe post hoc test. Mean values clearly reveal a significant decrease in the fluoride release from day 1 to day 21 for both groups. Non-coated group released significantly more fluoride than surface coated group (P<0.001). It can be concluded that nanofilled surface coating agent will reduce the amount of fluoride released into oral environment as compared to non-coated group and at the same time releasing fluoride into surrounding cavity walls to create zones of inhibition into the cavity floor to help internal remineralization.

The purpose of this study was to evaluate and compare in vitro the fuoride release and uptake from 5 different esthetic restorative materials. Materials tested were conventional GIC - Fuji 7, GC (group1), resin modifed GIC - Vitremer, 3M ESPE (group 2), polyacid modifed composite - Dyract, Dentsply (group 3), fuoride releasing composite - Tetric ceram, Ivoclar Vivadent (group 4), Giomer-Beautifl, Shofu (group 5). Fluoride release was estimated at 6th, 24th, 48th hour and weekly interval for 5 weeks. For fuoride recharge, each specimen was exposed to 2 ml of 1.23% APF gel for 4 minutes and fuoride release measured at 1st, 2nd, 3rd day and 7th day. The fuoride release and recharge was measured using fuoride ion specifc electrode. ANOVA and Tukey HSD test were used for statistical analysis. During tested period all materials showed statistically different capability to release and uptake fuoride. Groups 1 and 2 results were comparable in fuoride release. Similarly groups 3 and 5. Groups 1 and 2 vs 3, 4, 5 were statistically very highly signifcant. Only conventional GIC showed initial 'burst effect'. Materials tested showed potential for fuoride release and recharge. Different esthetic materials had variable fuoride release hence selection of materials should be guided by specifc clinical situations.

Aim:The aim of this study was to compare constituents of glass powder, fluoride release, and antimicrobial properties of new atraumatic restorative treatment material with zirconia fillers and conventional glass ionomer cement (GIC) type IX.Materials and Methods:Thisin vitro study comparing Zirconomer and Fuji IX was executed in three parts: (1) energy dispersive X-ray microanalysis of glass powders (2) analysis of fluoride release at 1st, 3rd, 7th, 15th, and 30th day, and (3) antimicrobial activity against Streptococcus mutans, Lactobacillus casei, and Candida albicans at 48 hours. Data was analyzed using unpaired t-test and two way analysis of variance followed by least significant difference post hoc test. A P value of < 0.05 was considered statistically significant.Results:Energy dispersive X-ray microanalysis revealed that, in both Zirconomer and Fuji IX glass powders, mean atomic percentage of oxygen was more than 50%. According to the weight percentage, zirconium in Zirconomer and silica in Fuji IX were the second main elements. Calcium, zinc, and zirconium were observed only in Zirconomer. At all the time intervals, statistically significant higher amount of fluoride release was observed with Zirconomer than Fuji IX. At 48 hours, mean ± standard deviation (SD) of zone of inhibition against Streptococcus mutans was 11.14 ± 0.77 mm and 8.51 ± 0.43 mm for Zirconomer and Fuji IX, respectively. Against Lactobacillus casei, it was 14.06 ± 0.71 mm for Zirconomer and 11.70 ± 0.39 mm for Fuji IX. No antifungal activity was observed against Candida albicans by Zirconomer and Fuji IX.Conclusion:Zirconomer had higher antibacterial activity against Streptococcus mutans and Lactobacillus casei, which may be attributed to its composition and higher fluoride release. However, it failed to show antifungal effect againstCandida albicans.

Objectives: The objective was to evaluate fluoride and acid release from four glass ionomer cements (GICs) over time and to evaluate and compare their effect on Streptococcus mutans over time. Materials and Methods: The fluoride and acid release from the prepared samples (GICs, Miracle Mix, Fuji IX, d-tech ® , Ketac Molar) were measured daily using digital fluoride meter and pH meter, respectively, after placing them in deionized distilled water for 15 days. The water was replaced daily. The samples were aged by placing them in distilled water for 1, 3, 5, and 7 days. The antimicrobial activity was assessed by measuring the zone of inhibition around the samples (fresh and aged) placed on the bacterial cultures after 48 h of incubation. Mean and standard deviation were calculated. Pearson’s correlation coefficient was used. P < 0.05 was considered statistically significant. Results: The antimicrobial activity of the four GICs was greatest immediately after the cements were mixed. The greatest fluoride and acid release was from d-tech. Conclusion: Both acid and fluoride release that contributed to the antibacterial activity of the Glass ionomer cements reduced significantly as the cement aged.

Fluoride is a common constituent in most of the rocks and the release of fluoride into groundwater is the major problem in several parts of the world. The present study was carried out with the objective of identifying sources and mechanism of release of fluoride from the rocks and its impact on human health in Vaniyar river basin, Dharmapuri district, Tamil Nadu. Groundwater samples were collected from 44 wells once in 2 months from June 2011 to August 2014 and analyzed for major cations and anions using an ion chromatograph. The possible reasons for the increased concentration of fluoride in groundwater of the area were investigated by taking into account of the agricultural practises and the major rock types in the area. The observed order of the dominance of cations in groundwater in the study area is Na+ > Ca2+ > Mg2+ > K+ and that of anions is Cl− > HCO3− > SO42− > CO3− > F−. The fluoride concentration in groundwater of this region ranges from 0.15 to 6.14 mg/l. Out of 569 samples analysed, fluoride concentration exceeded the maximum permissible limit of the drinking water standards of BIS 1.5 mg/l in 396 samples. Many people living in this area are suffering from dental and skeletal fluorosis due to prolonged use of fluoride-rich groundwater for drinking. Concentration of fluoride in groundwater is relatively low in wells located in charnockite region, whereas the concentration of fluoride in groundwater is high in the deep wells in regions comprising of epidote hornblende biotite gneiss. The major source of fluoride in groundwater in the area is due to leaching of fluoride-bearing minerals. Fluoride ions from biotite and hornblende minerals leach into the groundwater and contribute high fluoride concentration in this region. The concentration of fluoride in groundwater increases when the water level is deep indicating higher release of fluoride from greater depth. The geochemical reactions that control the release of fluoride from fluoride-bearing minerals such as biotite and hornblende into groundwater were identified. Removal of high concentration of fluoride from drinking water is necessary in this region and measures should be taken to supply water after removal of fluoride for the betterment of the livelihood in the area.

An in vitro investigation of a poly(vinyl phosphonic acid) based cement with four conventional glass-ionomer cements. Part 1: flexural strength and fluoride release

Objectives: The fluoride-releasing properties of restorative materials are crucial for the prevention of secondary caries as these can act as fluoride reservoirs. Hence, the present study aimed to investigate, assess, and compare the impact of time, temperature, and storage conditions on the fluoride release of silorane-based composites (SBCs) and methacrylate-based composites (MBCs), and also evaluate the variation in their reuptake of fluoride (after recharge). Methods: SBC and MBC test samples of 10 mm × 2 mm dimensions were prepared and tested for fluoride release and recharge in distilled water and artificial saliva at temperatures of 4 °C, 37 °C, and 55 °C. The amount of fluoride released (at 1, 7, 14, and 28 days) and re-released after recharge (with 5000 ppm neutral sodium fluoride (NaF) solution for 5 min at 1, 3, and 7 days for 3 weeks) were studied with the help of a fluoride-selective ion electrode. Results: SBCs had a greater release of fluoride at low temperature in artificial saliva (0.07 ± 0.03) when compared to MBCs (0.04 ± 0.005). Fluoride release increased on day 7 but decreased over time (p < 0.05). Fluoride re-release was greater in MBCs than SBCs and it increased with time (p < 0.05). Conclusion: The amount of fluoride release and recharge depends on the time interval, temperature, and storage condition. These restorative materials can serve as fluoride reservoirs and contribute to sustained fluoride release in oral fluids, thereby preventing the initiation of secondary caries and the failure of restorations. In addition, it may assist in developing measures to improve fluoride delivery for topical applications.

AimThis study evaluated the 12-month ion release, fluoride recharge capacity, pH modulation, mechanical aging, and structural reliability of an experimental amorphous calcium phosphate (ACP)-based composite compared to contemporary bioactive restorative materials.MethodsAn experimental ACP composite was compared with Activa™ BioACTIVE-Restorative, Cention N, and Surefil one ™. Calcium (Ca2+), phosphate (PO43−), and fluoride (F−) release, along with pH changes, were assessed over 365 days in artificial saliva. Fluoride recharge was performed at six months using a single application of 5000 ppm sodium fluoride gel, followed by cumulative fluoride re-release measurement for 30 days. The flexural strength and modulus were evaluated at baseline, 6 months, and 12 months. Statistical analysis was conducted using mixed-model ANOVA with post-hoc tests, and flexural strength reliability was assessed using Weibull analysis (α = 0.05).ResultsAll materials exhibited an initial burst of ion release, followed by a progressive decline (p = 0.001). The ACP composite demonstrated the highest early calcium and phosphate release but negligible fluoride release and significant reductions in mechanical properties and reliability after aging. Cention N showed sustained multi-ion release, the greatest alkalizing capacity, and stable mechanical performance. Surefil one™ achieved the highest fluoride release and recharge capacity while maintaining a near-neutral pH and superior mechanical reliability. The Activa™ BioACTIVE-Restorative exhibited moderate ion release and intermediate mechanical performance.ConclusionsBioactive restorative materials exhibit distinct material-dependent behaviors. Alkasite-based systems showed balanced ion release and mechanical stability, fluoride-focused systems demonstrated superior recharge and reliability, and the ACP composite provided primarily short-term calcium–phosphate release with limited long-term durability.

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.

This systematic review aimed to assess the clinical performance of modified glass ionomer cements (GICs) in restoring primary teeth. The focus was on evaluating their longevity, marginal adaptation, wear resistance, caries prevention, and overall durability in primary teeth. Following PRISMA 2020 guidelines and PROSPERO registration, a systematic search was conducted across PubMed, Scopus, and Google Scholar for studies published between 2014 and 2024. Sixteen eligible studies were included. Risk of bias was assessed using the Cochrane ROB 2 tool. Clinical performance was evaluated based on standardized criteria, including USPHS, FDI, and Ryge systems. Resin-modified GIC (RMGIC) and high-viscosity GIC (HVGIC) demonstrated better marginal integrity and wear resistance than conventional GIC. Nano-modified GICs, such as Ketac Nano, showed improved mechanical strength and esthetics. Bioactive and alkasite-based materials (e.g., Cention N) offered therapeutic benefits like fluoride release and remineralization, along with good clinical durability. Conventional GICs showed higher failure rates, particularly marginal breakdown, while modified GICs exhibited reduced failure over 12–36 months. However, variations in evaluation criteria and limited long-term data on newer materials restricted the strength of comparisons. The study concluded that modified GICs, particularly RMGIC, HVGIC, and bioactive formulations, show promising clinical performance in primary teeth restorations. Their selection should consider caries risk and cavity size. While current evidence supports their use, future studies with standardized protocols and long-term follow-ups are necessary to establish their sustained efficacy.

Background:The cariostatic action associated with fluoride-releasing restorative materials is mainly attributed to a sustained release of fluoride. This research aims on comparing Cention N and Zirconomer Improved in vitro fluoride release and re-release.Methods:Test materials were grouped into two categories containing 15 samples each. The cumulative fluoride release and re-release measurements was made during 1st, 7th and 15th day. The independent sample t-test and paired t-test was used to check mean differences. The level of significance was kept at p<0.05.Results:At day 1, 7 and 15 the initial fluoride release of zirconomer group was significantly higher (p<0.05) than the cention group. It was found that from day 1 to day 7 the mean initial fluoride release has significantly reduced (p<0.05) for both the groups. Similar results were also seen when comparisons were done between day 7 to day 15 (p<0.05) and day 1 to day 15 (p<0.05) for both the groups.Conclusion:Zirconomer was more efficient in initial and fluoride re-release than the Cention N restorative material. Further in vivo studies with more parameters are recommended to evaluate fluoride release and cariostatic performance of Cention N and Zirconomer in real environmental circumstances.

The effect of layered double hydroxide on fluoride release and recharge from a commercial and an experimental resin varnish

Glass ionomer cement (GIC) is an excellent example of dental materials that revolutionized the way we approach restorative dentistry. There have been several studies aimed at improving the properties of GIC while reducing its compressive strength, brittleness, etc.Over time, to combat this cumbersome problem, various agents have been added to GIC to increase its antimicrobial properties. The incorporation of fluoride, selenium, and other compounds has proven to reduce the rate of formation of cariogenic biofilm. However, the use of synthetic compounds such as fluoride can result in fluorosis. This calls for the need for a natural antimicrobial agent with minimal or no side effects and optimal effectiveness.Grape seed extract (GSE) and resveratrol (grape skin extract) are naturally occurring compounds having antibacterial, anti-inflammatory, and antioxidative properties. GSE and resveratrol were incorporated into conventional restorative GIC.Conventional and experimental restorative GICs were manipulated according to manufacturer instructions and were then tested for their compressive strength, shear bond strength (SBS), and fluoride release. Mean compressive strength was highest for GIC incorporated with GSE, followed by resveratrol incorporated GIC, with the least being in the control group. Mean SBS and fluoride release were highest in resveratrol incorporated GIC, followed by GSE incorporated GIC, with the least being in the control group. Positive results were observed, showing an increase in the properties of fluoride release, SBS, and compressive strength in GIC incorporated with plant-based extracts. GIC is routinely used in pediatric dentistry, requiring constant evolution to improve its properties. The incorporation of plant-based extracts in GIC is a natural alternative to synthetic additives while also enhancing its physical properties. Further studies are required to assess the long-term effect of the experimental adhesives in clinical trials. Yermalkar GS, Devendrappa SN, Gaonkar NN, et al. Comparative Evaluation of Compressive Strength, Shear Bond Strength, and Fluoride Release of Grape Seed Extract and Resveratrol Incorporated in Conventional Restorative Glass Ionomer Cement: An In Vitro Study. Int J Clin Pediatr Dent 2025;18(2):167-172.