首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
The aim of the present study was to evaluate the fluoride uptake/release of polyacid-modified resin composites (compomers) in neutral and acidic buffer solutions. Two compomers (Dyract and Compoglass) were tested and the conventional glass-ionomer cement (GIC) Vivaglass Base served as a control. Forty specimens were fabricated from each of the respective materials. Twenty of these specimens were placed in artificial saliva and the other 20 specimens in a fluoridated dentifrice slurry for 5 min. Then, 10 fluoridated and 10 non-fluoridated specimens were immersed in a neutral buffer solution (pH 6.8), and the other specimens were immersed in an acidic solution (pH 4.0). After 1, 2, 3, 4, and 5 days the samples were again placed in either a fluoridated dentifrice slurry or saliva for 5 min, after which time they were transferred to fresh buffer solutions. The fluoride content of the solutions was assessed with a fluoride sensitive electrode. Fluoride release from all the materials decreased continuously during the experiment, with a significantly higher release in the acidic solution compared to the neutral buffer solution. Fluoridation did not result in an increased fluoride release for the compomers. However, the conventional GIC revealed a significantly higher fluoride release after fluoridation. It is concluded that Dyract and Compoglass can not be replenished with fluoride, irrespective of the pH value of the environment.  相似文献   

2.
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...  相似文献   

3.
OBJECTIVES: The purposes of this study were to compare the fluoride ion release from a freshly mixed polyacid-modified resin composite, or "compomer" (Dyract), and 3 resin-modified glass-ionomer cements (Fuji II LC, Photac-Fil, and Vitremer) and to compare the use of 3 units for measuring fluoride release. METHOD AND MATERIALS: Five specimens (3.0 x 2.7 mm) of each material were prepared. The specimens were placed in polypropylene vials with 2 mL of deionized water and stored at 37 degrees C. The solutions were replaced weekly and the levels of fluoride ions were analyzed at days 1, 7, and 30 and subsequently every 28 days for 253 days. Fluoride measurements were carried out using a fluoride ion-selective electrode connected to a pH ion-selective electrode meter. Fluoride ion release was measured in parts per million, micrograms per square centimeter, and micrograms per cubic millimeter. RESULTS: Fuji II LC, Photac-Fil, and Vitremer showed high initial release values, which decreased exponentially and then showed a slow decline during the ensuing time. Dyract released significantly less fluoride ions during the first 84 days than did the 3 resin-modified glass-ionomer cements and maintained this low level of release throughout the study period. The amounts of fluoride ion release measured at any time interval varied with the units of measurement chosen, but the pattern of release remained the same. CONCLUSION: There was a wide variation in the amounts of fluoride ions released from related products, but the patterns of release were similar and unaffected by the units of measurement used.  相似文献   

4.
The present study compared the initial fluoride release and release following refluoridation of a conventional glass-ionomer Ketac-Molar (ESPE), a resin-modified glass-ionomer, Vitremer (3M), and two compomers F-2000 (3M) and Hytac (ESPE). Fifteen test specimens were prepared for each brand and immersed in deionized water. The fluoride released was measured every 2 days for 22 days. Refluoridation of the test specimens was done with solutions of 0.02, 0.04 and 0.2% NaF for 5 min on days 22, 30, 38 and 46. The fluoride released from recharged specimens was measured every 2 days until day 54. The fluoride release was highest during the first days after preparation, after which it decreased sharply and then more slowly. The four materials became 'recharged' with fluoride following repeated fluoride exposure in solution, the 0.2% solution being the most effective. From a clinical point of view, the results from this study imply that all the restorative materials tested may act as intra-oral devices for the controlled slow release of fluoride at sites at risk of recurrent caries. Fluoride release and uptake by four new fluoride releasing restorative materials.  相似文献   

5.
summary Conventional glass-ionomer cements with varying amounts (5–15%) of borax (Na2B4O7.10H2O) as modifier were prepared. These mixtures were spatulated with an aqueous solution of polyacrylic acid with a powder to liquid (P/L) ratio of 1.5:1. Properties such as working time, setting time, compressive strength, diametral tensile stength, solubility and fluoride release of these cements were determined. It was observed that the working time and setting time of the resultant cements shortened with the addition of borax. Certain physical properties such as compressive and diametral tensile strength, solubility and disintegration of these glass-ionomer cements deteriorated with borax addition but fluoride release from them was unaffected.  相似文献   

6.
Four glass-ionomer cements were examined for solubility by measuring the fluoride release from a simulated dental restoration. From this study it may be concluded: 1. Glass-ionomer cements as luting agents for dental prostheses release significant quantities of fluoride. 2. Commercially available cements vary in the amounts of fluoride released. 3. The cements with lower powder-to-liquid ratios demonstrated greater fluoride release. 4. The significant release of fluoride indicated that glass-ionomer cements could be effective in reducing caries.  相似文献   

7.
Most of the data reported on the release of fluorides from glass-ionomer cements are based upon measurements made in de-ionized water. De-ionized water does not represent the complex chemistry of the oral environment. In this study, an artificial saliva solution was used, and the data on the fluoride ions released into it from four glass-ionomer cements were compared with those obtained in de-ionized water. The glass-ionomer cements used were: Ketac-Fil (ESPE), Ketac-Silver (ESPE), Fuji-II (GC), and Miracle Mix (GC). Ten disc samples (2 cm x 0.1 cm) of each cement were prepared. Each was individually suspended in either de-ionized water or artificial saliva (five samples in each medium) and stored for 24 h at 37 degrees C, then transferred to fresh media for a total of 60 days. Collected media were buffered with TISAB, and fluoride was measured by a specific electrode. Artificial saliva was prepared according to Fusayama et al. (1963). The data obtained showed that: (1) glass-ionomer cements released more fluoride in de-ionized water than in artificial saliva; (2) Ketac-Fil released 20% more fluoride in saliva than did Fuji-II, the latter releasing 49% more fluoride than Ketac-Fil in de-ionized water; and (3) conventional glass ionomers released more fluoride than did meta-reinforced ones in both media.  相似文献   

8.
OBJECTIVES: This study investigates the effect of a neutral citrate solution on the fluoride release of 10 acid-base setting glass ionomer cements during 140 days at 37 degrees C. METHODS: Five disks of 10 acid-base setting restorative glass ionomers were prepared according to the manufacturer's instructions. These specimens were immersed individually in 25 ml of a 0.01 mol/l citrate solution with pH = 7. Over 140 days, the solutions were regularly renewed and the fluoride concentration eluted during each period was determined with a combined fluoride ion selective electrode. RESULTS: The cumulative fluoride release was the result of an initial high release that ceased after some time and a long-term of low fluoride release. The long-term fluoride release was higher in neutral citrate solution than in water. For some formulations the short-term fluoride release also was higher in neutral citrate solution than in water suggesting that the polysalt matrix composition could be important in this respect. SIGNIFICANCE: The fluoride release process is due not only to a loss of relatively loosely bound fluoride in the cement matrix, but also to the release of strongly bounded fluoride inducing a long-term fluoride release. The effect of citrate on the fluoride release process may increase depending on the acid (polyacrylic acid versus copolymers of polyacrylic acid) used for the polysalt formation in the hardening cement. Depending on the competition between the polyacrylate anion and the citrate anion for the metal cation extraction the fluoride release process may be retarded.  相似文献   

9.
目的 比较1种复合体和4种树脂化玻璃离子水门汀在水中释放氟离子的能力。方法 用氟离子选择电极,分别在第1、7、30d直径253d,5种材料固化后标本浸泡训的氟离子浓度。结果 除复合体以外的所有材料,均显示了高的初期氟离子释入并急剧下降,然后缓慢下降。结论 复合体释放的氟离子比树脂化玻璃离子水门汀少。对于龋病高发的患者,选择高氟离子释放的树脂化玻璃离子水门汀材料较好。  相似文献   

10.
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).  相似文献   

11.
PURPOSE: The purpose of this study was to evaluate the amount of fluoride released from compomer restorative materials after immersion in various media. MATERIALS AND METHODS: In this test, four materials were used: three compomers (Dyract, Dentsply, Konstanz, Germany; Compoglass, Vivadent, Schaan, Principality of Liechtenstein; and Xeno, Sankins, Tochigi, Japan) and one resin-modified glass ionomer cement (Fuji II LC, GC, Tokyo, Japan). There were four test solutions: one alcoholic (whiskey), two low-pH drinks (Coca-Cola, orange juice), and one deionized water. Over a period of 60 days, the tested specimens were immersed in the test solution for 3 hours every day, then kept in deionized water. The fluoride released was detected by using a fluoride ion selective electrode connected to a microprocessor ion analyzer. The fluoride ion concentration (ppm) of the test solutions and deionized water was recorded after 1, 2, 3, 4, 7, 30, and 60 days. Electron probe microanalysis was used for surface analysis of the fluoride released. RESULTS: When immersed in low-pH soft drinks, compomer showed a significantly higher fluoride release than when immersed in deionized water (p < .0001). For specimens immersed in Coca-Cola, the fluoride release levels (microgram/cm2, mean +/- SD) at 1, 7, and 60 days for Dyract (91.6 +/- 1.8, 39.3 +/- 3.1, 10.5 +/- 0.9), Compoglass (129.5 +/- 0.9, 66.5 +/- 2.7, 19.0 +/- 0.3), Fuji II LC (147.0 +/- 4.2, 50.8 +/- 3.1, 27.6 +/- 3.0), and Xeno (73.6 +/- 3.2, 27.3 +/- 2.1, 6.6 +/- 0.6) demonstrated the trend of significantly lower releases with time in water solution. Over a 60-day period, materials immersed in 100% orange juice released the highest amount of fluoride, which could be attributable to the erosive effect of the medium. Materials immersed in deionized water released the least amount of fluoride. Among the tested compomers, Compoglass released the most fluoride.  相似文献   

12.
The aims of this study were to observe the release of fluoride ions (F-) from GC-Fuji Lining-LC(R) glass-ionomer cement, to assess the diffusion process, and to measure fluoride diffusivity (D) in the set cement. Specimens of various dimensions and shapes, ranging from discs to cylindrical rods, were fabricated for both open and embedded modes of testing. In the open mode studies, specimens with different surface to volume ratios were selected and immersed in 37 degrees C distilled water. In the embedded mode studies, only one diametral surface of the rod-shaped specimens of different lengths and diameters was exposed. F- concentration was measured using a fluoride electrode. The storage solution was analysed at predetermined intervals hourly, daily, and weekly (up to 10 weeks). Immediately after each sampling, the old storage solution was discarded and replaced with new distilled water. F- release from the set cements was detectable (0.4-3.8 ppm, varied with sample geometry), even after a 10-week sampling interval. F- release was greater in ground set cements (0.37 ppm/mg powder) than in control samples of unmixed powder (0.01 ppm/mg powder) immersed for 1 h. Two mechanisms for F- release were proposed. One was short-term and involved rapid dissolution from the cement surface. The other was more gradual and resulted in the sustained diffusion of ions through the bulk cement, which can be modelled by applying a mathematical technique known as separation of variables to Fick's Second Law of Diffusion. The mean D of F- in embedded set cements of glass-ionomer was (1.4+/-0.5)x10-11 cm2/s, with higher apparent D observed in open mode samples [(7.6+/-1.4)x10-11 cm2/s].  相似文献   

13.
Purpose: The purpose of this study was to evaluate the amount of fluoride released from compomer restorative materials after immersion in various media. Materials and Methods: In this test, four materials were used: three compomers (Dyract, Dentsply, Konstanz, Germany; Compoglass, Vivadent, Schaan, Principality of Liechtenstein; and Xeno, Sankins, Tochigi, Japan) and one resin‐modified glass ionomer cement (Fuji II LC, GC, Tokyo, Japan). There were four test solutions: one alcoholic (whiskey), two low‐pH drinks (Coca‐Cola, orange juice), and one deionized water. Over a period of 60 days, the tested specimens were immersed in the test solution for 3 hours every day, then kept in deionized water. The fluoride released was detected by using a fluoride ion selective electrode connected to a microprocessor ion analyzer. The fluoride ion concentration (ppm) of the test solutions and deionized water was recorded after 1, 2, 3, 4, 7, 30, and 60 days. Electron probe microanalysis was used for surface analysis of the fluoride released. Results: When immersed in low‐pH soft drinks, compomer showed a significantly higher fluoride release than when immersed in deionized water (p <.0001). For specimens immersed in Coca‐Cola, the fluoride release levels (pg/cm2, mean ± SD) at 1, 7, and 60 days for Dyract (91.6 ± 1.8, 39.3 ± 3.1, 10.5 ± 0.9), Compoglass (129.5 ± 0.9, 66.5 ± 2.7, 19.0 ± 0.3), Fuji II LC (147.0 ± 4.2, 50.8 ± 3.1, 27.6 ± 3.0), and Xeno (73.6 ± 3.2, 27.3 ± 2.1, 6.6 ± 0.6) demonstrated the trend of significantly lower releases with time in water solution. Over a 60‐day period, materials immersed in 100% orange juice released the highest amount of fluoride, which could be attributable to the erosive effect of the medium. Materials immersed in deionized water released the least amount of fluoride. Among the tested compomers, Compoglass released the most fluoride. CLINICAL SIGNIFICANCE The results of this study indicate that, at low pH, compomer restorative materials tend to release more fluoride.  相似文献   

14.
This investigation evaluated the fluoride-releasing properties of various fluoride-releasing restorative materials, including resin-modified glass-ionomer cements (Fuji ionomer TypeII LC, Photac-Fil Aplicap, Vitremer), compomers (Ionosit FIL, Compoglass, Dyract) and fluoride-releasing resin composites (Heliomolar radiopaque, Degufill mineral). The study also estimated the effects of those materials on the inhibition of artificial secondary caries around restorations using a bacterial caries-inducing system. The amount of fluoride released from the materials in deionized water was measured every one week for 10 weeks. Class V cavities with the gingival margin located in the root were prepared in extracted human premolars and restored with each of the materials. The restored teeth were incubated in the bacterial artificial caries chamber, and the artificial lesion created around the restoration was observed microradiographically. The resin-modified glass-ionomer cements released the largest amount of fluoride and created a thick radio-opaque zone in the artificial lesion along the restoration-dentin interface. These results indicated that the fluoride-releasing restorative materials have the potential to inhibit secondary caries formation around restorations. Resin-modified glass-ionomer cements presented a particularly strong effect, compared with compomers and fluoride-releasing resin composites.  相似文献   

15.
OBJECTIVES: The aim of this study was to evaluate the fluoride release from aged resin composites containing different types of fluoridated glass filler into both deionized distilled water and lactic acid solution. METHODS: Three resin composites, UniFil S (containing fluoro-alumino-silicate glass filler), Reactmer (containing pre-reacted glass-ionomer filler) and Beautifil (containing both types of fillers) were used. A conventional glass-ionomer cement, Ketac-Fil, was used as a control. Five disk specimens of each material were prepared and aged in water for 10 weeks. After aging, specimens were immersed in deionized distilled water for a further 6 days and then in aqueous lactic acid (pH 4.0) for 2 days. This process was repeated twice more and the specimens were subsequently immersed in water for a further 12 days. Fluoride release was measured every 2 days throughout the post-aging period. RESULTS: The amount of fluoride release for aged UniFil S and Beautifil markedly increased in acid solution compared with water storage. The difference was not so great for aged Reactmer and Ketac-Fil. UniFil S and Beautifil gave significantly greater fluoride release in water following immersion in acid solution (p<0.05, two-way ANOVA and Scheffe's test), but Reactmer and Ketac-Fil showed no such increase in fluoride release after acid immersion. SIGNIFICANCE: These results suggested that the nature of the fluoridated glass filler within a resin composite and the way in which the material interacts with an acidic environment affected the amount of fluoride released.  相似文献   

16.
STATEMENT OF PROBLEM: Viscoelastic behavior can influence the fracture properties of glass ionomers, which is of clinical relevance. Glass-ionomer cements can display viscoelastic behavior, defined as having displacement rate- or strain rate-dependent mechanical properties. Understanding and describing the viscoelastic behavior of glass ionomers is important to understanding their clinical behavior. PURPOSE: The purpose of this study was to evaluate the viscoelastic behavior of 6 glass-ionomer cements and determine whether there was a correlation to fracture toughness. MATERIAL AND METHODS: Three conventional glass-ionomer cements (alpha-Silver, alpha-Fil, and Ketac-Molar) and 3 resin-modified glass-ionomer cements (Vitremer, Fuji II LC, and Photac-Fil Quick) were evaluated using measurements of compressive strength (CS), flexural strength (FS), and diametral tensile strength (DTS) at displacement rates of 0.5, 1.0, 1.5, and 2.0 mm/min. The CS and DTS specimens were cured in glass tubes and cut to 4 x 6-mm and 4 x 2-mm disk-shaped specimens, respectively. The FS specimens were cured in bar molds (2 x 2 x 15 mm). The fracture toughness (FT) specimens were cured in a minicompact mold to obtain precracked specimens. The mechanical testing results were compared statistically using generalized linear model/analysis of covariance and the Ryan-Einot-Gabriel-Welsch multiple range test at the alpha=.05 level. RESULTS: For all 3 mechanical properties, there was a displacement-rate dependence on the mechanical property. However, there were no differences in the displacement-rate dependence based on the type of material-conventional glass ionomer or resin-modified glass ionomer-for any of the mechanical properties. Only for FS test was there a significant difference based on the brand of material. There was no statistical difference in FT among the glass-ionomer cements tested, although the resin-modified glass ionomers tended to display higher FT. CONCLUSION: A larger sample size and a much wider range of crosshead speeds are necessary to support a correlation between viscoelastic behavior and FT.  相似文献   

17.
The objective of this study was to determine long term release of fluoride from a resin-modified glass-ionomer cement (RMGIC) (Fuji II LC (FLC)) compared with that from two conventional acid-base setting cements (HiDense (HD) and KetacSilver (KS)) marketed for similar restorative purposes. Fluoride release from discs of cement immersed in water or artificial saliva was measured for 2.7 years using an ion selective electrode technique. The RMGIC was affected by water if immersed immediately after setting. This is similar to conventional acid-base cements and the experimental method was designed to allow for this. Over the 2.7-year period, the RMGIC and HD released similar amounts of fluoride into both water and artificial saliva. In water, the RMGIC released the most fluoride, while in artificial saliva the highest release was from HD. KS released the least amount of fluoride in both immersing liquids. In artificial saliva, release was reduced to 17-25% of that found in water, with the RMGIC showing the greatest reduction. Both acid-base cured cements showed changes in colour over the 2.7-year span, while the colour of the RMGIC was stable. It was concluded that the RMGIC released equivalent or greater amounts of fluoride than the two acid-base cure glass-ionomers over a period of 2.7 years.  相似文献   

18.
OBJECTIVE: To investigate the flexural strength and fluoride release of four conventional glass-ionomer cements: Ketac-Molar (KM), HiFi (HF), Vivaglass Fil (VF), Ketac-Fil (KF) and a newly developed glass polyphosphonate cement, Diamond Carve (DC). METHOD: Disc specimens (10 mm diameter, 1 mm thick) were prepared and mould stored at 37 degrees C. After one hour, the specimens were removed from their mould and immersed in 20 ml of deionised water until required for testing. Biaxial flexural strength was determined at 1 hour and at 1, 7, 30 and 90 days after the start of mixing. Measurements of fluoride release from the specimens were carried out at 2 hours and at 1, 3, 7, 14, 30, 60 and 90 days after the start of mixing using a fluoride ion selective electrode. The results were analysed using ANOVA and student 't' tests. RESULTS: All the materials displayed different flexural strength patterns. KM and DC became stronger whilst KF and VF plateaued in strength with time. HF peaked in strength and then became weaker. At 90 days, the mean flexural strengths in decreasing order was as follows: KM > or = VF > or = DC > or = HF > KF. An initial fast rate of fluoride release followed by a slower but steady release of fluoride was observed in each of the materials. The mean cumulative fluoride release in decreasing order was as follows: VF > KF > or = HF > DC > KM. VF released significantly higher level and KM significantly lower level of fluoride than the other materials. CONCLUSIONS: The acid used to form the cement could not be used to predict changes in cement strength behaviour with respect to time. DC increased in strength with time and its flexural strength at 90 days was comparable to that of HF and VF. The cumulative and rate of fluoride release varied for the materials. DC had a low fluoride release consistent with a fast setting material with good early resistance to water.  相似文献   

19.

Objective:

The aim of this study was to investigate how the release of fluoride from two compomers and a fluoridated composite resin was affected by exposure to KF solution.

Material and Methods:

Two compomers (Dyract AP and Compoglass F) and one fluoridated composite (Wave) were prepared as discs (6 mm diameter and 2 mm thick), curing with a standard dental lamp. They were then stored in either water or 0.5% KF for 1 week, followed by placement in water for periods of 1 week up to 5 weeks total. Fluoride was determined with and without TISAB (to allow complexed and decomplexed fluoride to be determined), and other ion release (Na, Ca, Al, Si, P) was determined by ICP-OES.

Results:

Specimens were found not to take up fluoride from 100 ppm KF solution in 24 h, but to release additional fluoride when stored for up to five weeks. Compomers released more fluoride cumulatively following exposure to KF solution (p<0.001), all of which was decomplexed, though initial (1 week) values were not statistically significant for Dyract AP. Other ions showed no variations in release over 1 week, regardless of whether the specimens were exposed to KF. Unlike the compomers, Wave showed no change in fluoride release as a result of exposure to KF.

Conclusions:

Compomers are affected by KF solution, and release more fluoride (but not other ions) after exposure than if stored in water.  相似文献   

20.
The purposes of this study were to evaluate the diametral tensile strength and the water sorption of restorative (Fuji IX and Ketac Molar) and resin-modified glass-ionomer luting cements (ProTec Cem, Fuji Plus and Vitremer) mixed at both manufacturer and increased powder: liquid ratio, for their use in the Atraumatic Restorative Treatment. A conventional restorative glass-ionomer (Ketac Fil) was used as control. Specimens (6.0 mm in diameter x 3.0 mm in height) were prepared and stored (1 hour, 1 day and 1 week) for a diametral tensile strength test. Data were subjected to two-way ANOVA and Tukey tests (p<0.05). For the water sorption test, specimens of 15.0 mm in diameter x 0.5 mm in height were prepared and transfered to desiccators until a constant mass was obtained. Then the specimens were immersed in deionized water for 7 days, weighed and reconditioned to a constant mass in desiccators. Data were subjected to one-way ANOVA and Tukey tests (p<0.05). Five specimens of each studied material and consistency were prepared for each test. The resin-modified glass-ionomer cements showed significantly higher strength than the conventional materials. Except for ProTec Cem, the diametral tensile strength of the resin-modified materials significantly increased from luting to restorative consistency. Except for ProTec Cem, the water sorption of the resin-modified glass ionomers was higher than the others. The water sorption of resin-modified materials at restorative consistency was significantly lower than at luting consistency. Resin-modified glass-ionomer luting cements mixed at increased powder: liquid ratio showed better properties than at luting consistency.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号