Salivary contamination and bond strength of glass-ionomers to dentin

This study evaluated the effect of salivary contamination on the shear bond strength of two highly viscous glass ionomer cements (Fuji IX GP Fast and Ketac-Molar Maxicap) to conditioned dentin and assessed the effect of cleaning the contaminated field prior to bonding. The buccal surfaces of 90 human molars and premolars were ground to expose dentin and the teeth were then set in resin. The specimens were divided into two groups for each material, then further subdivided into three groups of 15 teeth each: Group 1--uncontaminated (control), Group 2--dentin contaminated with saliva, Group 3--dentin contaminated, washed and air dried. The specimens were made by bonding the test material to dentin using a 4 mm diameter gelatin capsule. All specimens were protected with varnish and placed in distilled water at 37 degrees C for seven days prior to measuring bond strength in shear. Fractured surfaces were examined visually and by using SEM to assess mode of failure. There were no significant differences in mean shear bond strength among the three test groups for either material (ANOVA). However, shear bond strength of Fuji IX to dentin was significantly greater than Ketac-Molar (p=0.019) for all groups. Weibull analysis showed that contaminated (Group 2) specimens had a greater probability of failure at low stresses. Modes of failure were mostly cohesive for Fuji IX and adhesive/cohesive for Ketac-Molar. In conclusion, salivary contamination did not affect the mean shear bond strength of Fuji IX GP Fast and Ketac-Molar Maxicap to conditioned dentin; however, it increased the probability of failure at low stresses.     

Clinical effects of glass ionomer restorations on residual carious dentin in primary molars

PURPOSE: To evaluate the mineralization and morphology of residual (infected and affected) carious dentin following the restoration of vital primary molars with viscous glass-ionomer cement (GIC). METHODS: Encapsulated Fuji IX GP and Ketac-Molar Aplicap GICs were placed in cavities that were prepared using the atraumatic restorative treatment (ART) approach. Four suitable exfoliated teeth with intact restorations were sectioned and then examined by electron probe microanalysis (EPMA) and scanning electron microscopy (SEM). RESULTS: EPMA demonstrated the presence of fluorine and strontium that had penetrated into the underlying residual carious dentin from the adjacent GIC. The concentrations of these two elements, and those of calcium and phosphorous, varied with distance from the GIC/dentin interface. SEM showed varying degrees of dentin tubule destruction and intratubular (peritubular) dentin present immediately subjacent to the GIC/dentin interface. Incomplete removal of carious dentin was observed in all specimens, and GIC remained adherent to the tissue.     

Comparison of atraumatic restorative treatment and conventional restorative procedures in a hospital clinic: evaluation after 30 months.

OBJECTIVE: The purpose of this study was to evaluate two glass-ionomer cements placed in the occlusal surfaces of permanent molar teeth, using two cavity preparation methods. METHOD AND MATERIALS: Three dentists placed 149 restorations for 68 patients in a hospital clinic. Atraumatic restorative treatment or conventional cavity preparation methods were used for two encapsulated, high-strength conventional glass-ionomer cements: Fuji IX GP and Ketac-Molar. Non-gamma 2 amalgam alloy was used in conventional preparations for comparison. RESULTS: The restorative procedures were uneventful, but cavity preparations made with atraumatic restorative treatment hand instruments took approximately twice as long as did conventional rotary instrumentation. After 30 months, only one glass-ionomer cement restoration had failed. Both glass-ionomer cements showed high early losses of sealant material, but caries was not detected in the exposed fissures. Both glass-ionomer cements also showed relatively high restoration wear. At 30 months, the mean cumulative net occlusal wear was 119 +/- 12 mm for Fuji IX GP and 96 +/- 13 mm for Ketac-Molar; the difference was not statistically significant. Color matching improved significantly by 6 months; there was no significant difference in color match between the two glass-ionomer cements by 12 months. Minor surface tarnishing and marginal discrepancies were present in the amalgam restorations and increased with time. CONCLUSION: The occlusal restorations performed satisfactorily over periods of up to 30 months. However, the continued deterioration of the cements requires longer-term studies to be undertaken.     

Bonding of contemporary glass ionomer cements to dentin.

OBJECTIVE: The objective of this study was to investigate the microtensile bond strength (microTBS) of contemporary glass ionomer cements (GIC) to sound coronal dentin. METHODS: Three specimen teeth were prepared for each material tested: Fuji IX GP (GC), ChemFlex (Dentsply) and Ketac-Molar Aplicap (ESPE). GIC buildups were made according to the manufacturers' instructions. After being stored at 37 degrees C, 100% humidity for 24h, the teeth were vertically sectioned into 1x1mm beams for microTBS evaluation. Representative fractured beams were prepared for scanning (SEM) and transmission electron microscopic (TEM) examination. RESULTS: Results of the microTBS test were: Fuji IX GP (12.4+/-8.6MPa), ChemFlex (15.0+/-9.3MPa) and Ketac-Molar Aplicap (11.4+/-7.7MPa). One-way ANOVA and a multiple comparison test showed that ChemFlex had a statistically higher microTBS (p<0.05). SEM fractographic analysis showed that the predominant failure modes were interfacial and mixed failures. The GIC side of the fractured beams revealed dehydration cracks, a high level of porosity, and voids with an eggshell-like crust. TEM analysis of the demineralized dentin sides of the fractured beams revealed the presence of an intermediate layer along the GIC-dentin interface. This zone was present on the fractured dentin surface in the case of interfacial failure, and beneath GIC remnants in specimens that exhibited a mixed failure mode. SIGNIFICANCE: The findings suggest that the bonding of GIC to dentin is not weak and that the microTBS values probably represent the weak yield strengths of GICs under tension.     

Spreadability of two glass ionomer cements used in atraumatic restorative treatment (ART).

'Press finger' in atraumatic restorative treatment (ART) is used to spread a glass ionomer cement (GIC) to seal the restoration margin and adjacent pits and fissures. This study compared the spreadability of Fuji IX and Ketac-Molar to establish which was best suited for this purpose. Twenty equally spaced cavities (35 mm apart) were machine-cut in each of two Perspex slabs 200 x 100 x 20 mm. Each cavity was 3 mm deep with a 4 mm diameter. Two V-shaped grooves 1 mm deep were cut to traverse the cavities: one 0.5 mm wide, the other 0.25 mm wide. Equal amounts (0.25 ml) of GIC were dispensed, 20 cavities for Fuji IX and 20 for Ketac-Molar and condensed under light finger pressure using a 20 mm diameter cork thinly coated with petroleum jelly. This allowed the GIC to be condensed into the cavity and spread into the differently sized grooves. The samples were stored in deionised water for 24 hours whereafter the length to which the GIC had spread along each groove from the cavity edge was measured to the closest 0.01 mm. The data were analysed using ANOVA and the unpaired Student's t-test (P < 0.05). There was a statistically significant difference between the length of spread of the two GICs (t = 2.534; P = 0.013) which was confined to the 0.25 mm width groove (t = 2.83; P = 0.007) with Fuji IX spreading much further along the groove (10.25 +/- 1.17 mm) than Ketac-Molar (7.66 +/- 4.21 mm). Fuji IX appears to be the better sealant material when selecting for spreadability in ART.     

Shear bond strength of glass-ionomer cements to air-abraded dentin

PURPOSE: The aim of this in vitro study was to evaluate the shear bond strength of two conventional glass-ionomer cements to bovine dentin when using the air-abrasion technique for cavity preparation. MATERIALS AND METHODS: Forty bovine central incisors were selected, embedded in polyester resin, and ground until the dentin surface was exposed. The teeth were randomly assigned to four groups: I and II--rotating instrument with a carbide bur; III and IV--an air-abrasion system. Groups I and III were restored with Fuji IX and groups II and IV with Ketac Molar. A 3-mm-diameter bonding site was delimited and treated with 10% polyacrylic acid for 10 s in the Fuji IX subgroups and with 25% polyacrylic acid for 10 s in the Ketac Molar subgroups. After surface treatment, a glassionomer cylinder was prepared for each specimen, using a split bisected Teflon matrix. The finished specimens were submitted to the shear bond strength test in a universal testing machine at a crosshead speed of 0.5 mm/min. The data were analyzed using ANOVA and Scheffé statistical tests. The dentin bonding areas were analyzed under a stereoscopic optical magnifier (40X) to assess the type of failure. RESULTS: The mean (SD) shear bond strengths in MPa were: group I--3.49 (+/- 3.77), group II--7.17 (+/- 2.93), group III--7.55 (+/- 2.99), group IV--5.67 (+/- 3.90). Ketac Molar showed higher bond strength values in bur-prepared cavities, while on the air-abraded preparations, Fuji IX showed superior results. CONCLUSION: It can be concluded that the air-abrasion system used for cavity preparations may influence the bonding performance of conventional glass-ionomer cements to dentin.     

Physiological remineralization of artificially demineralized dentin beneath glass ionomer cements with and without bacterial contamination in vivo

This study evaluated the physiological remineralization of artificially demineralized dentin beneath glass ionomer cements with and without bacterial contamination. The artificially demineralized dentin was produced on 84 monkey teeth using a decalcifying solution. Half the samples were left open to the oral cavity for one week, then, all cavities were restored with two glass-ionomer cements: Fuji IX or Fuji II LC improved (n = 7). The nanohardness of the artificially demineralized dentin at 3, 90 and 360 days was measured using a nanoindentation tester (ENT-1100, Elionix) and compared statistically by two-way ANOVA and Fisher's PLSD test (p < 0.05). Each mineral (Ca, Mg, P, F) within the demineralized dentin was also analyzed using Electron Probe Microanalysis. For the samples, the mean nanohardness of the three-day samples was significantly lower than the 360-day samples (p < 0.05). Although there was no significant difference in the mean nanohardness within all the bacterially-contaminated groups through the experimental periods (p > 0.05), the mean nanohardness of the bacterial-contaminated samples were significantly lower than the non-bacteria-contaminated samples (p < 0.05). From the EPMA results, fluoride release from both cements to the bottom of the artificially demineralized dentin was detected within three days. Although Ca density was sparse within this demineralized dentin lesion, for the Fuji IX sample, a high Mg density within this lesion was detected at 360 days.     

Influence of different adhesive restorative materials on mutans streptococci colonization

PURPOSE: To evaluate the effect of some restorative materials on mutans streptococci colonization. METHODS: Awild strain of mutans streptococci was isolated from human dental plaque and a monospecific biofilm adherent to the surfaces of 12 adhesive restorative materials (F2000, Dyract AP, Compoglass F, Z100 MP, Filtek Z250, Clearfil, Ketac-Bond, Ketac-Fil Plus, Ketac-Molar, Fuji Cap II, Fuji Bond LC and Fuji II LC) were tested. A colorimetric technique (MTT assay), based on the reduction of a yellow tetrazolium salt to a purple formazan, was used to evaluate the biomass adherent to the disk surfaces after a 24-hour growth. RESULTS: One-way ANOVA showed that glass-ionomer cements (Fuji Cap II, Ketac-Bond, Ketac-Fil and Ketac-Molar) had similar antibacterial effects on mutans streptococci and were significantly more effective (P < 0.001) than all other products tested in reducing the biofilm development on their surfaces. The compomers (Dyract, Compoglass F and F 2000) showed a significantly higher value of bacterial colonization than all the other materials (P < 0.001).     

Comparison between two glass-ionomer sealants placed using finger pressure (ART approach) and a ball burnisher

PURPOSE: To compare in vitro marginal leakage and fissure penetration depth of sealants placed under finger pressure (ART) and a ball burnisher. METHODS: High-viscosity glass-ionomer hand-mixed Fuji IX GP and encapsulated Fuji IX GP Fast were used to seal 72 patent occlusal pits and fissures according to the ART approach or with the aid of a ball burnisher in surgically removed molars. All teeth were thermocycled for 500 cycles in water between 6 and 55 degrees C, then varnished until 1 mm from the sealant, submerged in 1% methylene blue for 4 hours, had roots dissected, crowns embedded in epoxy resin and sectioned before examination with a light reflection microscope. Marginal leakage at the enamel-sealant interface and fissure penetration depth was measured on a scale of 0 to 4. RESULTS: There was no statistically significant difference in marginal leakage (P= 0.62) and fissure penetration depth (P= 0.46) between sealants placed using the application procedures. One of the operators scored statistically significant lower on the marginal leakage and higher on fissure penetration depth in sealants produced using finger pressure than with a ball burnisher (P= 0.01). All nine sealants placed by this operator using finger pressure and encapsulated glass-ionomer showed no marginal leakage. The mean fissure penetration depth of these sealants was 3.6 (SD=0.9).     

Bioactive glass-ionomer cement with potential therapeutic function to dentin capping mineralization

We have developed a novel bioactive resin-modified glass-ionomer cement system with therapeutic function to dentin capping mineralization. In the system, the newly synthesized star-shape poly(acrylic acid) was formulated with water, Fuji II LC filler, and bioactive glass S53P4 to form resin-modified glass-ionomer cement. Compressive strength (CS) was used as a screening tool for evaluation. The commercial glass-ionomer cement Fuji II LC was used as a control. All the specimens were conditioned in simulated body fluid (SBF) at 37 degrees C prior to testing. The effect of aging in SBF on CS and microhardness of the cements was investigated. Scanning electron microscopy was used to examine the in vitro dentin surface changes caused by the incorporation of bioactive glass. The results show that the system not only provided strengths comparable to original commercial Fuji II LC cement but also allowed the cement to help mineralize the dentin in the presence of SBF. It appears that this bioactive glass-ionomer cement system has direct therapeutic impact on dental restorations that require root surface fillings.     

Morphological interface between hybrid ionomers and dentin with and without smear-layer removal

To evaluate the micromorphological interface between dentin and several hybrid ionomer restoratives, a flat dentin surface was obtained on the occlusal surfaces of extracted human molar teeth after sectioning the enamel with an Isomet saw. Three poly-acid-modified composite resins, Compoglass, Dyract and F2000, and two resin-modified glass-ionomer cements, Fuji II LC and Photac-Fil were applied to the dentin surface. A second section, 2 mm apical from the first one, was made to produce a dentin segment containing the tested materials. Each disc was then split fractured along the dentin/material interface. For the poly-acid-modified composites, one half of the disc was stored in 6 mol/L HCl for 48 h to remove the dentin. The other was gently decalcified and deprotenized at the interface between the hybrid ionomer and the dentin. Both halves were then sputtered with gold and examined using SEM. For resin-modified glass-ionomer, samples were only evaluated at the interface. The three poly-acid-modified composite resins showed the formation of hybrid layers and resin tags at the interface to the dentin. Removal of the smear layer significantly improves hybridization of these materials. Also, Fuji II LC produced a hybrid layer while the Photac-Fil showed no evidence of hybridization.     

放射性龋齿充填治疗的临床效果评估

目的　评估放射性龋充填治疗的临床疗效。方法　对 1 5例放射性龋患者的 1 4 6个龋洞分别采用Ketac Molar和FujiIX充填 ,各充填 73个龋洞。临床观察 2年后 ,用美国公共健康部制定的评定系统 (USPHS)进行疗效评估。结果　①Ketac Molar和FujiIX 2年的完好率分别为 51 7%和52 3 % ,差异无显著性 (P >0 0 5)。②治疗失败及缺陷主要发生在术后 1年和 2年 ,失败的主要原因是充填体脱落 ,边缘着色是两组材料共有的缺陷。③两组材料除在固位情况方面差异极显著外 (P <0 0 1 ) ,其他项目差异均无显著性 (P >0 0 5)。结论　放射性龋使用上述两种材料充填治疗 ,完好率较高 ,有较好的实用性 ,其中FujiIX更优于Ketac Molar。     

Longitudinal study on microleakage of three root-end filling materials by the fluid transport method and by capillary flow porometry

AIM: (i) To compare the root-end sealing ability of IRM Caps (IRM), Fuji IX Capsules (Fuji IX) and Pro Root MTA Tooth-Coloured Formula (MTA) in teeth obtained from cadavers. (ii) Further research on leakage study methodology by means of comparison of the fluid transport method (FTM) and capillary flow porometry (CFP). METHODOLOGY: Root canal treatment was performed on 33 cadaver teeth in situ 2 weeks prior to root resection and ultrasonic retropreparation (S12/90 degrees D-tip on Suni-Max), after which the teeth were retrieved from the cadavers. Two teeth were kept as positive and negative controls. The other teeth were divided in three different groups at random, with each group receiving one of the retrofill materials. Retrofills were exposed to water 5 min after placement. The teeth were stored at 37 degrees C for 12 h after which the root filling was removed. Microleakage (L in microL day(-1)) was measured for 24 h under a pressure of 1.2 atm using FTM and recorded as L = 0, 0 < L < or = 10, L > 10. The measurements were repeated after 1 and 6 months. After 6 months, leakage was also assessed by CFP in order to measure through pores and their diameters. Results were analysed statistically using nonparametric Kruskal-Wallis and Mann-Whitney U-tests, and Spearman correlation coefficients between the results of both methods were calculated. The level of significance was set at 0.05. RESULTS: (i) A statistically significant difference could be demonstrated between Fuji IX and IRM at 1 month with FTM. FTM revealed a significant difference between Fuji IX and the other materials at 6 months, whereas CFP did not. However, using both methods, Fuji IX showed the best result. (ii) When comparing both techniques, CFP demonstrated through pores in all teeth, whereas with FTM in only 14 of the 31 teeth could through pores be demonstrated. A positive correlation between both methods was demonstrated. CONCLUSIONS: Under the conditions of this study (i) the conventionally setting glass-ionomer cement Fuji IX showed the best results when used as a root-end material and (ii) CFP appeared to be a useful method for leakage evaluation of through pores in endodontics.     

Clinical investigation of two glass-ionomer restoratives used with the atraumatic restorative treatment approach in China: two-years results.

OBJECTIVE: To compare the clinical performance of two glass-ionomer cements, ChemFlex (Dentsply DeTrey) and Fuji IX GP (GC), when used with the atraumatic restorative treatment (ART) approach in China. METHODS: Eighty-nine school children aged between 6 and 14 years who had bilateral matched pairs of carious posterior teeth were included. A split-mouth design was used in which the two materials were randomly placed on contralateral sides. The performance of the restorations was assessed directly and also indirectly from die-stone replicas at baseline and after 6, 12, and 24 months. RESULTS: The 24-month cumulative survival rates of ART restorations in the primary teeth were 93 and 90% for the ChemFlex and Fuji IX GP class I restorations, respectively, while 40 and 46% of class II restorations placed with the respective materials were satisfactory. In the permanent dentition, only class I restorations were involved and the cumulative survival rates were 95 and 96% for ChemFlex and Fuji IX GP. For the primary teeth after 24 months, net mean occlusal wear was 87 microm for ChemFlex and 85 microm for Fuji IX GP. The occlusal wear in the permanent teeth was 75 microm for ChemFlex and 79 microm for Fuji IX GP. CONCLUSION: The clinical performance of both materials over a 24-month period was similar and the survival rates of class I ART restorations in both primary and permanent teeth were high.     

Clinical evaluation of the ART approach and materials in peri-urban farm schools of the Johannesburg area.

In this study, 1,325 school children from 7 farm schools were examined. Their mean age (+/- SD) was 10.5 +/- 3.0 (range 6-11) years. At baseline, the mean DMFT score was 1.1 +/- 1.7 and 36.4% of the children had caries. The prevalence of fluorosis among the children was 12.6%. Curative treatment was offered to all the children. A total of 113 children (8.5%) with one-surface cavities on permanent teeth and without fluorosis were treated using the atraumatic restorative treatment (ART) approach. A total number of 163 cavities were included in the study, of which 82 were treated with Fuji IX glass-ionomer cement and 81 with Ketac-MOLAR (hand mix). One year after treatment, restoration and sealant parts of ART fillings were examined. Caries status was also determined. The placing of the ART fillings and their evaluation were performed by different practitioners. A total number of 108 restorations (58 with Fuji IX, 50 with Ketac-MOLAR) were evaluated. Results of ART fillings showed a survival rate of 93.1% with Fuji and 94.0% with Ketac-MOLAR. Retention of the sealant parts of ART fillings was observed in 81% of restorations with Fuji IX and 76% with Ketac-MOLAR, not connected to the filled cavity. Caries was absent on all teeth restored with Fuji IX and noted in only one tooth restored with Ketac-MOLAR, not connected to the filled cavity. The retention rate after a 12-month period was acceptable and ART approach proved to be an appropriate technique for restoring teeth in this population group. There were no statistically significant differences between the survival rates of the two glass-ionomer restorative materials (P > 0.05).     

Microscopic evaluation of the interface between glass-ionomer cements and tooth structures prepared using conventional instruments and the atraumatic restorative treatment (ART) technique.

OBJECTIVE: The purpose of this study was to evaluate the effect of cavity preparation using hand instruments and conventional rotary instruments on the bonding of glass-ionomer cements to formerly carious teeth. METHOD AND MATERIALS: In 2 experimental groups (12 teeth each with primary caries) caries was removed and cavities prepared using hand instruments according to the atraumatic restorative treatment (ART) technique or conventional rotary instruments. In the control group (12 caries-free teeth) Class 1 cavities were prepared using conventional instrumentation. Cavities in all teeth were restored with 1 of the commercial glass-ionomer cements designed for use with the ART technique, either Fuji IX (GC) or Ketac Molar (3M Espe). After 21 days of storage in physiologic saline at 37 degrees C, 3 400-microm-thick slices from each tooth were stained using the Mallory method and evaluated using a light transmitting microscope. RESULTS: In all samples, a region of interaction was observed between the cement and dentin and enamel. However, the interface in teeth from which caries had been removed was different from that in the control group. All were stained using Mallory staining, but only teeth which had been carious showed coloration. No differences were found in intensity of color or appearance between the cavity preparation techniques. CONCLUSION: The occurrence of caries in a tooth alters the bonding behavior of glass ionomers to that tooth. The method of caries removal (ART or conventional preparation) does not influence the quality of the interface between a glass ionomer and either dentin or enamel.     

The influence of dynamic fatigue loading on the separate components of the bracket-cement-enamel system

PURPOSE: To evaluate the influence of cyclic loading and type of adhesive on the shear bond strength of the bracket-cement-enamel bond. METHODS: The materials studied were: Transbond XT (a Bis-GMA resin composite cement), Fuji Ortho LC (a resin-modified glass-ionomer cement), and Fuji IX Fast (a conventional glass-ionomer cement). The shear bond strength (SBS) and the shear bond fatigue limits (SBFL) were determined after 72-hour storage in 37 degrees C water for the cement itself, the button-cement interface, the cement-enamel interface, and the bracket-cement-enamel system. The SBFL was determined with the aid of the "staircase method" at 10,000 cycles. The results were analyzed using ANOVA and Tukey HSD post hoc test (P < 0.05). RESULTS: ANOVA showed significant differences between the SBS of the materials. Fatigue was observed in all substrate combinations, with the exception for the Fuji IX Fast cement-enamel and the Fuji Ortho LC bracket-cement-enamel combinations.     

Crack closure on rehydration of glass-ionomer materials

Moisture-sensitivity of immature glass-ionomer cements suggests that hydration-induced volumetric expansion might close and potentially heal established cracks. Crack closure in glass-ionomer cements (GICs) was observed following rehydration. Circular cavities were prepared in 15 teeth: 10 were restored with resin-modified GICs (5 with Fuji II LC and 5 with Photac-Fil) and 5 were restored with a conventional GIC (Fuji IX); all were dehydrated for 1 min with air and imaged immediately by confocal microscopy. Crack formation in each was located, after which water was placed on the surface and observed for 15 min via a CCD camera. Dehydration caused cracks with measurable gaps, while rehydration resulted in varying degrees of closure: closure was limited in the conventional GIC, and complete or near complete along part/s of the crack in the resin-modified GICs. In all, closure movement became imperceptible after the first 10 min. Statistical analysis indicated no significant difference between the closure behavior of all materials. However, the resin-modified GICs appeared to show a greater potential for closure of established cracks than the conventional GIC upon rehydration.     

The effects of two cavity preparation methods on the longevity of glass ionomer cement restorations: an evaluation after 12 months

BACKGROUND: The authors undertook a study to evaluate the effect of two cavity preparation methods on the initial survival of two more-viscous glass ionomer cements, or GICs, placed in the occlusal surfaces of permanent molar teeth. METHODS: Three dentists placed 149 restorations in 68 adult patients in a hospital clinic. They used either atraumatic restorative treatment, or ART, or conventional cavity preparation methods to place two encapsulated esthetic conventional GICs: Fuji IX GP (GC International Corp., Tokyo) and Ketac-Molar Aplicap (3M ESPE, Seefeld, Germany). For comparison, they used high-copper-content GK Amalgam Alloy (Advanced Technology & Materials Co. Ltd., Beijing) in conventional preparations. They evaluated the restorations using both direct and indirect observation methods. RESULTS: Cavity preparations for which the authors used ART hand instruments took approximately twice as long to complete as did those for which they used conventional rotary instruments. After 12 months, no restorations had failed, but restorations comprising both GICs showed early losses of adjacent sealant material. Both GICs also showed relatively high restoration wear. At 12 months, the mean cumulative net occlusal wear for Fuji IX GP was 77 +/- 47 micrometers, and for Ketac-Molar 83 +/- 51 microm, without statistical significance (P > .05). Color matching improved significantly with time (P < .001), without significant differences in color between the two GICs by 12 months (P = .09). The amalgam alloy had minor surface tarnishing and marginal discrepancies increased with time (P < .00 1). CONCLUSIONS: All of the occlusal restorations were rated as satisfactory after 12 months. The method of cavity preparation did not affect the restoration performance of the GICs. However, their deterioration requires long-term monitoring. Clinical Implications. The more viscous GICs appear initially suitable for restricted use in clinical practice when placed using either of two cavity preparation methods in the occlusal surfaces of permanent molar teeth in adults.     

A comparative study of fluoride uptake from dentin bonding agents and glass-ionomer cements in permanent and primary tooth enamel.

OBJECTIVE: Many fluoride-releasing dental materials are being sold on the basis of their cariostatic properties. However, the amount of fluoride release of these materials is still uncertain. The aim of this study was to determine the amount of fluoride uptake in primary and permanent tooth enamel from 1 conventional glass-ionomer cement (Fuji II), 1 resin-modified glass-ionomer cement (Fuji II LC), and 2 fluoride-releasing dentin bonding agents (Liner Bond 2 and Optibond) in vitro. METHOD AND MATERIALS: One hundred sixty caries-free primary and permanent molar teeth were assigned to the study. Materials were applied according to the manufacturer's instructions to standard windows created on the enamel surfaces. The amount of fluoride uptake by enamel was investigated by using a specific fluoride electrode and acid-etching biopsy technique. RESULTS: The amount of fluoride taken up from Fuji II and Fuji II LC by permanent and primary tooth enamel was found to be statistically significant. However, no significant fluoride uptake from Optibond and Liner Bond 2 was found. CONCLUSION: Fuji II and Fuji II LC glass-ionomer materials seemed to provide more effective fluoride release than did Optibond and Liner Bond 2 in permanent and primary enamel.