Fluoride release, weight loss and erosive wear of modern aesthetic restoratives.

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.     

Effects of APF gel on the physical structure of compomers and glass ionomer cements

This study assessed the effect of an acidulated phosphate fluoride (APF) gel on the surfaces of eight modern esthetic restorative materials. Five specimens each of three high powder: liquid ratio conventional glass ionomer cements (ChemFlex, Fuji IX GP, Ionofil Molar), four polyacid-modified resin composites (compomers) (Compoglass F, Dyract AP, Freedom, F2000) and an alkaline glass filled resin composite (Ariston pHc) were prepared and immersed at 37 degrees C in 2 mL of artificial saliva for six weeks. The aged specimens were then coated with 1.23% APF gel for four minutes, rinsed and again immersed in artificial saliva for another six weeks. The immersed, fresh specimens for each material were then examined with SEM and surface profilometry. After APF gel application, mean surface roughness (Ra) measurements and SEMs showed that roughness increased significantly, generally from the resin composite and compomers to the conventional glass ionomer cements (p < 0.05).     

Effects of artificial saliva and APF gel on the surface roughness of newer glass ionomer cements

OBJECTIVES: To investigate the surface roughness changes of newer esthetic dental restorative materials with aging and acid erosion in a simulated oral environment. METHODS: The materials included two viscous conventional glass ionomer cements originally marketed for the ART approach, one resin-modified glass ionomer cement and two resin composites. Ten specimens for each material were prepared according to the manufacturers' instructions, then each specimen was immersed in 2 ml of buffered artificial saliva at 37 degrees C for three weeks. For each material, five specimens (Group B) were then coated with 1.23% acidulated phosphate fluoride (APF) gel for four minutes, rinsed and immersed again in artificial saliva for another three weeks. Gel was not applied to the Group A specimens. For each material, the surface roughness of an additional three fresh specimens and those from Groups A and B were evaluated using a profilometer and SEM. RESULTS: The resin composites showed the least effects of acidic corrosion on their surface texture. The viscous glass ionomer cements showed the greatest changes, with significantly increased surface roughness p<0.001). CONCLUSIONS: The immersion of two newer viscous GICs in a buffered artificial saliva and the single application of APF gel resulted in significantly rougher surfaces over a relatively short six-week period.     

Fluoride release and uptake by aged resin-modified glass ionomers and a polyacid-modified resin composite

Little has been reported of the relationship of fluoride release and weight loss, and the effects of use of different fluoride agents on restorations, for the new generation of glass ionomer cements. The objectives of this study were to compare fluoride release of fresh and aged specimens of a polyacid-modified resin composite (Dyract), and of three resin-modified glass ionomer cements (Fuji II LC, Photac-Fil, Vitremer); and to correlate fluoride release and weight loss of aged specimens after recharging with three different fluoride agents. All materials showed high initial fluoride release immediately after uptake when using the agents. However, the levels of fluoride release dropped rapidly soon afterwards. Although initial fluoride release was significantly different between Dyract and the three resin-modified glass ionomers, when different fluoride agents were used on aged specimens after recharging, no significant differences were found after the first few hours. Linear regression analyses also showed no correlation between cumulative fluoride release and weight loss. Possible beneficial oral health effects may only be expected by frequent exposure of these materials to fluoride agents.     

In vitro fluoride release from aesthetic restorative materials following recharging with APF gel

In this in vitro study, the fluoride ion release from three more-viscous conventional glass ionomer cements (GICs)--ChemFlex, Fuji IX GP, Ionofil Molar--four polyacid-modified resin composites (compomers)--Dyract AP, Compoglass F, Freedom, F2000--and a hybrid resin composite--Ariston pHc--were compared. The amounts of fluoride release from 3 x 2.7 mm specimens were measured over six weeks using a fluoride ion-selective electrode. After six weeks, the specimens were recharged with 2 ml of 1.23 per cent acidulated phosphate fluoride (APF) gel for four minutes. The recharged specimens were then assessed for the amounts of fluoride release over another six weeks. Statistical analyses were performed using one-way and repeated measures ANOVA. The GICs and Compoglass F showed significantly higher initial fluoride release rates during the first two days (p < 0.05). After the first two days, fluoride release rates from all materials dropped quickly and became essentially stabilized within three-five weeks, in an exponential mode. The recharging of the specimens with APF gel caused a brief, but significant, increase in fluoride release for all materials (p < 0.05), before decreasing to previous comparable rates. Compoglass F released relatively more fluoride, and Ariston pHc relatively less, after APF gel application than before. The lowest total amounts over the study were released by Dyract AP and Freedom. The newer compomers, as well as the newer more-viscous GICs, appear to act as fluoride reservoirs to varying extents.     

Compressive strength, surface roughness, fluoride release and recharge of four new fluoride-releasing fissure sealants

The aim of this study was to investigate the compressive strength and surface roughness of two glass ionomer cements and two resin-based fissure sealants before and after fluoride release and recharge. Twenty-one specimens were prepared and divided into three groups for each material. First group was loaded in compression until failure. Fluoride released was measured from the remaining specimens, and then the second group of seven specimens was loaded at 28th day. The remaining seven specimens were exposed to 0.05% NaF solution and 1.23% APF gel. Fluoride amount was measured, and the last group was loaded at 70th day. Surface roughness measurement of five more disk-shaped specimens from each material was also carried out. After exposure to APF gel, all materials were recharged. At the end of experimental period, it was found that surface roughness increased, whereas compressive strength decreased, over time. In conclusion, fluoride-releasing fissure sealants could act as show, rechargeable fluoride release systems. However, if a fissure sealant exhibited high fluoride release, it had inferior mechanical properties.     

四种玻璃离子充填材料释氟性与溶解性的研究

目的 比较4种玻璃离子充填材料短期内氟离子释放能力和溶解性,为临床选择充填材料提供依据.方法 实验选取1种传统型玻璃离子水门汀(SC),2种高强度玻璃离子水门汀FujiⅨ(F9)和Ketac Moler(KM),1种树脂改良型玻璃离子水门汀FujiIILC (F2LC),和1种复合树脂Z100( CR,3M)共5种材...     

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.     

Fluoride release of glass ionomer-based luting cements in vitro.

STATEMENT OF PROBLEM: There is considerable variation in generic formulation and in reported fluoride release from resin-modified glass ionomer luting cements. PURPOSE: This study compared fluoride release from 2 generically similar resin-modified glass ionomer luting cements (Vitremer and Advance) with release from 2 conventional glass ionomer luting cements (Ketac-Cem and Fuji I). MATERIAL AND METHODS: Ten specimen disks of each of the 4 luting cements were fabricated and immersed in deionized water in individual polystyrene jars. The jars were stored in a humidor at 37 degrees C between test periods. At the same time each day, for 28 days, fluoride release from each specimen disk was measured in parts per million by testing the storage water. RESULTS: The 4 luting cements tested showed an initial high concentration of fluoride release during the first week, followed by a gradual decrease over the study period. Vitremer luting cement demonstrated the greatest mean cumulative fluoride release in parts per million over the study period (198), followed by Fuji I (140), Ketac-Cem (110), and Advance (99) luting cements. CONCLUSIONS: Resin-modified glass ionomer luting cements showed fluoride release comparable to the conventional glass ionomer luting cements. Vitremer luting cement released more fluoride over the 28-day period than the other cements.     

An in vitro investigation of marginal dentine caries abutting composite resin and glass ionomer cement restorations

BACKGROUND: There are a number of studies citing the primary reason for replacing auto cure glass ionomer cements was due to recurrent caries. The purpose of this study was to use an in vitro model to measure caries at the dentine restoration interface of bonded composite resin and auto cure glass ionomer cement restorations and to measure the amount of surface degradation occurring in the restorative materials. METHODS: Specimens of auto cure glass ionomer cements (Riva Fast, Fuji IX Fast, Ketac Molar Quick and Fuji VII) and bonded composite resin restorations (Ice, SDI) were placed separately at the dentino-enamel junction of 10 recently extracted human third molar teeth, disinfected and placed into the overflow from a continuous culture of S. mutans for two weeks. Restorations were sectioned and prepared for scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). Restoration tooth interfaces were photographed and the distance from the surface of the teeth to the surface of the restorations measured. EPMA of percentage weights of calcium, phosphorous and fluoride were made outwards from the restoration surface 130pm at a depth of 10 microm below the surface of the dentine. RESULTS: There were significant differences between the surface heights of composite resin, auto cure glass ionomer cements compared to teeth surfaces. Percentage weights of calcium and phosphorus levels were similar to non-demineralized dentine in the auto cure glass ionomer cement samples but there were significant reductions in mineral content of dentine adjacent to bonded composite resin restorations. Fluoride levels were mixed. CONCLUSIONS: This study shows that placing a bonded composite resin restoration into dentine affords little protection to the surrounding tooth from caries attack although insignificant degradation of the restorative surface occurs. Placing a glass ionomer cement restoration into dentine protects the surrounding tooth from caries but degradation of the restoration surface occurs.     

Effect of 1.23 percent APF gel on fluoride-releasing restorative materials

This study evaluated the effect of a 1.23 percent APF gel on the surface morphological characteristics and surface roughness of one high-viscosity (Fuji IX GP), three polyacid-modified resin-based composites (Dyract AP, F2000 and Compoglass F) (PMRC), and two resin-modified glass-ionomer cements (Vitremer and Fuji II LC). A microfilled nonfluoridated resin-based composite (Silux Plus) was used as a control. All materials were handled according to the manufacturers' instructions. The fluoride gel used in the study was a 1.23 percent acidulated phosphate fluoride gel (APF) (Nupro APF). The specimens were repeatedly exposed to the APF gel with cotton applicators for a period that simulated the equivalent of 4 yrs (1 min/6 mo) under prophylactic fluoride treatment. Average surface roughness (Ra) of the control and treated specimens was measured. Three separate Ra measurements along the direction of rotation of the finishing and perpendicular to the finishing direction and edge of the mold were made for each specimen surface. In each group, specimens with Ra closest to the mean were removed from the molds, sputter-coated with gold and examined using a scanning electron microscope. The results showed that all tested materials, except Vitremer, displayed increased surface roughness values following APF treatment. However, this was not statistically significant for Compoglass F, Vitremer and Fuji II LC. Among PMRC materials, F2000 displayed the highest Ra average value, although the differences between F2000 and Dyract AP and of Compoglass F and Dyract AP was not statistically significant. Comparisons of the Ra values between Silux Plus and the other test materials revealed statistically significant differences except for Dyract AP and Compoglass F. No statistically significant difference was found between the Ra values of Vitremer and Fuji II LC following APF treatment. Among all groups, Fuji IX GP displayed the highest surface roughness.     

Gradual surface degradation of restorative materials by acidic agents

The aim of this study was to investigate the effect of acidic agents on surface roughness and characteristics of four restorative materials. Fifty-two discs were created from each restorative material: metal-reinforced glass ionomer cement (Ketac-S), resin-modified glass ionomer cement (Fuji II LC), resin composite (Filtek Z250), and amalgam (Valiant-PhD); each disc was 12 mm in diameter and 2.5 mm thick. The specimens were divided into four subgroups (n=13) and immersed for 168 hours in four storage media: deionized water (control); citrate buffer solution; green mango juice; and pineapple juice. Surface roughness measurements were performed with a profilometer, both before and after storage media immersion. Surface characteristics were examined using scanning electron microscopy (SEM). Statistical significance among each group was analyzed using two-way repeated ANOVA and Tukey's tests. Ketac-S demonstrated the highest roughness changes after immersion in acidic agents (p<0.05), followed by Fuji II LC. Valiant-PhD and Filtek Z250 illustrated some minor changes over 168 hours. The mango juice produced the greatest degradation effect of all materials tested (p<0.05). SEM photographs demonstrated gradual surface changes of all materials tested after immersions. Of the materials evaluated, amalgam and resin composite may be the most suitable for restorations for patients with tooth surface loss.     

3种玻璃离子水门汀氟释放能力的体外研究

目的：对比研究3种玻璃离子水门汀在人工唾液中的氟释放能力。方法：选择FujiCem、FujiPlus和FujiI水门汀，分别制备10个直径4mm，高8mm的试样，每个试样浸入1ml人工唾液中，恒温37℃。采用离子选择电极分别于第1d、2d、3d、7d、14d、30d、90d测定3种材料的氟释放量。采用SPSS13．0软件进行统计分析。结果：3种材料均在第1d的氟释放量最高。第2d急剧下降，随后氟离子释放趋于平稳。在各个测量时间点，FujiCem的氟释放累积量最高，除了第1d外，FujiPlus释放量最低，且3种材料在90d测定的氟累积释放量总体均数间、组间两两比较均存在显著差异，P〈0．05，有统计学意义。结论：3种材料均能在一定时间内持续缓慢地向周围环境中释放氟离子，而FujiCem显示出更好的氟离子释放能力，在预防继发龋的发生方面具有一定的优势。     

Surface roughness of glass ionomer cements indicated for atraumatic restorative treatment (ART)

The purpose of this study was to evaluate the surface roughness of four conventional chemically cured glass ionomer cements (Fuji IX, Ketac Molar, Vidrion R and Vitromolar) commonly used in atraumatic restorative treatment (ART) immediately after material preparation. Twenty specimens of each glass ionomer cement were fabricated and surface roughness was measured after material setting. The specimens were further examined under scanning electron microscopy. Data were analyzed statistically by Kruskal-Wallis test and Mann-Whitney test at 5% significance level. Two-by-two comparisons showed statistically significant difference (p<0.05) between all materials, except for Ketac Molar and Vidrion R, which had statically similar results (p>0.05). Regarding their results of surface roughness, the materials can be presented in a crescent order, as follows: Ketac Molar < Vidrion R < Fuji IX < Vitromolar. In conclusion, from the tested glass ionomer cements, Fuji IX, Ketac Molar and Vidrion R presented acceptable surface roughness after setting reaction while Vitromolar showed remarkably higher surface roughness.     

Fluoride release and re-uptake in direct tooth colored restorative materials.

OBJECTIVES: Glass ionomers may be "recharged" through topical fluoride (F-) treatments; however, this reported "recharging," may be attributed to surface changes after F- treatment. This study examined differences in F- release and re-uptake among dual-cured and chemically-cured glass ionomers, and a photo-cured F- releasing composite. A secondary goal was to determine if tensile strength or surface roughness changed due to F- release, or F- re-uptake and re-release. METHODS: In Phase 1, initial surface roughness and diametral tensile strength were measured. F- release was measured for 30 days. Strength and roughness were then remeasured. In Phase 2, surface roughness was measured, then materials were treated with a 5000 ppm neutral F- gel, the same gel without F-, or phosphoric acid. F- release was measured for 30 days, then final surface roughness and strength were determined. RESULTS: Significant differences were found in amount and rate of F- release, and F- re-uptake and re-release among study materials and enamel controls (p < 0.001). The amount and rate of F- re-release after NaF treatment differed significantly from F- release after acid treatment in glass ionomers, although both groups showed increased F- release after surface treatment (p < 0.001). There were no significant changes in tensile strength or surface roughness after F- release or F- re-uptake and re-release as determined by ANOVA. SIGNIFICANCE: The results of this in vitro study indicate that applications of neutral 5000 ppm F- gel to aged glass ionomer restorations results in a significant fluoride uptake and subsequent release. The data suggest that the application of neutral fluoride gel to glass ionomer restorations in situ may result in increases in oral fluoride concentrations, without affecting the restoration's surface roughness or tensile strength.     

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.     

Effects of repeated fluoride varnish application on different restorative surfaces

AIM: The aim of this study was to assess the effect of repeated (twice) applications of two fluoride varnishes (Duraflor and CavityShield) on the surface micromorphology of a high-viscosity glass ionomer (Fuji IX GP), a compomer (F2000), and a flowable composite (Filtek Flow) using a profilometer and scanning electron microscope (SEM). METHODS AND MATERIALS: Fifteen specimens were prepared from each material, surface roughness (Ra) was measured with a profilometer, and an impression was made for epoxy replicas. The fluoride varnishes were applied to the experimental specimens of each material at repeated intervals of 48 hours. For all specimens, Ra was measured and SEM replicas were examined. RESULTS: The final Ra of glass ionomer was 3.49 +/- 0.59 (mean +/- SD) for CavityShield, 4.69 +/- 1.33 for Duraflor, and 2.96 +/- 1.53 for the controls. The final Ra of flowable composite was 0.53 +/- 0.20 for CavityShield, 2.61 +/- 3.08 for Duraflor, and 0.15 +/- 0.09 for controls. For glass ionomer and flowable composite, Duraflor was associated with a significantly higher roughness at the final measurement compared to controls (P < 0.05). SEM micrographs showed differing surface topographies which in many specimens confirmed Ra analysis. CONCLUSION: Fuji IX GP and Filtek Flow showed significantly higher roughness after two applications of Duraflor compared to controls.     

Effect of prophylaxis regimens on surface roughness of glass ionomer cements

This study investigated the surface roughness of conventional (Fuji II Capsulated [FC], GC Corporation, Tokyo, Japan), resin-modified (Fuji II LC [FL], GC Corporation) [FL] and highly viscous (Fuji IX GP Fast [FN], GC Corporation) glass ionomer cements [GICs] after exposure to five prophylaxis regimes. The surface roughness obtained was compared to untreated polished specimens (control). The prophylaxis regimes evaluated were rotating brush with pumice-water slurry [PB]; rotating rubber cup with pumice-water slurry [PC]; rotating rubber cup with prophylaxis paste [PP]; rotating rubber cup with prophylaxis gel [PG] and air-powder polishing [PJ]. Forty-eight specimens (3-mm long x 3-mm wide x 2-mm deep) were made for each material. The specimens were stored in distilled water at 37 degrees C for one month, polished with 1200 grit sandpaper using a lapping device and randomly divided into six groups (n=8). They were then stored for an additional two months in distilled water at 37 degrees C prior to exposure to the various prophylaxis regimens. The mean surface roughness value (Ra; microm) was measured with a profilometer. Data was subjected to ANOVA/Scheffe's tests at significance level 0.05. Mean Ra ranged from 0.30 to 1.70 microm for FC, 0.40 to 2.52 microm for FL and 0.36 to 1.79 microm for FN. Regardless of the type of glass ionomer, treatment with PJ resulted in significantly rougher surfaces when compared to the control group. For FC and FN, a significant increase in roughness was observed after treatment with PB and PP, respectively. Glass ionomer restorations may require re-polishing after exposure to some prophylaxis regimens.     

An FTIR study of the effects of artificial saliva on the physical characteristics of the glass ionomer cements used for art.

OBJECTIVE: To investigate the physical and chemical changes of five esthetic restorative materials in an artificial saliva using Fourier transform infrared spectroscopy (FTIR). METHODS: The materials included two glass polyalkenoate (ionomer) cements, one polyacid-modified resin composite, and two resin composites. Five fresh and 20 aged specimens for each material were immersed in 2 ml of artificial saliva at 37 degrees C for 1 week, 2 weeks, 1 month, and 2 months. They were examined by laser surface profilometer and FTIR. RESULTS: Surface roughness average (Ra) value showed significant differences among the physical properties of glass ionomers, polyacid-modified resin composite, and resin composites. SIGNIFICANCE: FTIR spectra showed that a major chemical changes in Fuji IX GP Fast glass ionomer cement in P-NH2 group bonding (900-1000 cm(-1)) that may explain the previously reported increase in microhardness after immersion. There was no direct correlation between surface roughness and spectral changes of the materials tested.     

Inhibitory effect on S. mutans by fluoride-treated conventional and resin-reinforced glass ionomer cements

The aim of the present study was to study the effect of fluoride gel treatment on fluoride release and inhibition of acid production of Streptococcus mutans by different glass ionomer cements. Test slabs of four glass ionomer materials were fitted into the bottom of a test tube. A layer of S. mutans cells was centrifuged onto the test slabs, and the specimens were incubated for 4 h in 1.7% sucrose solution. Incubations were made using fresh, aged (29 d), aged and F-treated (1.25% F-gel), and aged, F-treated and aged samples ( n = 15 per group). After each incubation, pH and F contents of the fluid phase were determined. The freshly mixed glass ionomer samples released large amounts of fluoride, and the pH fall in the fluid phase was significantly inhibited. For aged samples, the fluoride release decreased strongly and no inhibitory effect on acid production by S. mutans was seen. After application of fluoride gel, fluoride release and inhibitory effect were significantly higher than initially for all glass ionomer cements. In conclusion, all glass ionomer cements were able to take up fluoride and subsequently release it, which resulted in reestablishment of their antibacterial effect. The patterns of fluoride release and antibacterial action were virtually the same for conventional and resin-reinforced glass ionomer cements.