The present study compared and evaluated the shear bond strength (SBS) of two types of glass ionomer cement (GIC), Riva Self Cure HVTM (SDI Ltd., Victoria, Australia) and GC Fuji IX GP EXTRATM (GC America Inc., Alsip, USA) with and without the use of Riva Bond LCTM (SDI Ltd., Victoria, Australia), a lighted cured resin-modified glass ionomer cement (RMGIC) universal adhesive. Sixty extracted sound premolars with prepared exposure of the dentine on the occlusal surface were randomly assigned into four groups according to the tested restorative materials. Shear bond strength (SBS) tests were performed by using the Shimadzu Universal Testing Machine at a crosshead speed of 0.5 mm/minute, and the values obtained were statistically analysed using one-way ANOVA and Tukey tests. The inter-group comparison showed statistically significant differences in the SBS values between all the test groups (p < 0.001). A stereomicroscope was used to assess the modes of failure. Adhesive failures were predominant in adhesive groups (>80%) compared to higher cohesive failures found in the non-adhesive groups (>86%). A Spearman's rho correlation test performed to determine the association between SBS values and mode of failures had indicated positive correlations between the adhesive failure and SBS values in the adhesive groups (rs=0.86, p<0.001; rs=0.85, p<0.001) and the cohesive failure and SBS values in the non-adhesive groups (rs=0.87, p<0.001). These findings support the improvement in adhesion of GICs to tooth structure with the use of RMGIC adhesive.
Glass Ionomer Cements

ABSTRACT High viscous glass ionomer cement (HVGIC) was recently developed for atraumatic restorative treatment (ART). However, its moisture sensitivity remains a limitation thus protective coating application is recommended. This study investigated the effect of resin coating on the surface roughness and microhardness of two HVGICs (Riva Self Cure HVGIC [RV] and Equia® Forte Fil [EQ]) conditioned in food-simulating liquids (FSLs). Fifty standard disc-shaped samples were fabricated using customised stainless-steel mould (10 × 2 mm). Coating was applied on top surface of all samples and subsequently divided into five groups: air (control), distilled water, 0.02 N citric acid, heptane and 50% ethanol-water solution. The samples were conditioned in FSLs at 37°C for seven days. Subsequently, the surface roughness and microhardness of samples were measured using optical profilometry and microhardness tester, respectively. SEM analysis was done for qualitative observation of surface morphological changes. Data were analysed using one-way ANOVA, two-way ANOVA and posthoc Tukey’s test (α = 0.05). Interestingly, the results revealed that surface roughness was significantly influenced by FSLs immersion, presence of coating and the materials itself (p < 0.001). The lowest surface roughness was found on control coated samples: RV (50.98±4.25) nm and EQ (62.77±3.92) nm, while the highest values seen on uncoated surfaces in citric acid: RV (505.26±31.10) nm and EQ (350.33±15.36) nm. RV samples had the lowest microhardness of 54.97±2.48 Vickers hardness number (VHN) post-immersion in citric acid. In conclusion, with the exception of RV conditioned in heptane and ethanol, the uncoated HVGICs generally had higher surface roughness than the coated HVGICs. HVGICs conditioned in citric acid showed the most significant increase in surface roughness and reduction in microhardness.
Glass Ionomer Cements--adverse effects

OBJECTIVETo investigate the mechanical character, microleakage and mineralizing potential of nano-hydroxyapatite (nano-HAP)-added glass ionomer cement(GIC).

METHODS8% nano-HAP were incorporated into GIC as composite, and pure GIC as control. Both types of material were used to make 20 cylinders respectively in order to detect three-point flexural strength and compressive strength. Class V cavities were prepared in 120 molars extracted for orthodontic treatment, then were filled by two kinds of material. The microleakage at the composite-dentine interface was observed with confocal laser scanning microscope (CLSM) after stained with 1% rhodamin-B-isothiocyanate for 24 hours. Class V cavities were prepared in the molars of 4 healthy dogs, filled with composite, and the same molars in the other side were filled with GIC as control. The teeth were extracted to observe the mineralizing property with polarimetric microscope in 8 weeks after filling.

RESULTSThree-point flexural strength and compressive of nano-HAP-added GIC were increased compared with pure GIC (P < 0.001, P < 0.05). The nanoleakages and microleakages appeared at the material-dentine interface in the two groups, but there were more microleakages in control group than in experiment group (P = 0.004). New crystals of hydroxyapatite were formed into a new mineralizing zone at the interface of tooth and nano-HAP-added GIC, while there was no hydroxyapatite crystals formed at the interface of tooth and pure GIC.

CONCLUSION8% nano-HAP-added GIC can tightly fill tooth and have mineralizing potential, and can be used as liner or filling material for prevention.

This study investigated the effect of temporary cement and desensitizer on the bond strength of luting cements. Total 96 dentin specimens were divided into two groups with and without temporary cementation. For temporary cement-treated group, specimens were cemented with Temp-bond(R) and all specimens were stored in distilled water at 37 celsius degrees for 7 days. Each group was further divided into 3 subgroups with Gluma(R), One-step(R) application and without desensitizer. After desensitizer application, Ni-Cr specimens were luted to dentin surface with Panavia-F(R) and Vitremer(R). Specimens were placed in distilled water at 37 celsius degrees for 24 hours and shear bond strength between metal and dentin was measured by a universal testing machine. The results were as follows: 1. In Panavia-F(R) cemented groups, the combination of One-step(R) without temporary cement showed the greatest strength. Among the desensitizer types, One-step(R) showed the highest bond strength, followed by No-desensitizer, Gluma(R). 2. In Vitremer(R) cemented groups, the combination of no temporary cement and without desensitizer showed the greatest bond strength. Among the desensitizer types, No-desensitizer group showed the highest bond strength. 3. The use of Gluma(R) significantly reduced the shear bond strength in Panavia-F(R) and Vitremer(R) groups. 4. All temporary cement-treated groups showed a significant lower shear bond strength than without temporary cement groups. 5. Desensitizer application significantly influenced the bond strength of the resin cement and resin modified glass ionomer cement.
Cementation ; Dentin ; Glass Ionomer Cements ; Resin Cements ; Water

OBJECTIVETo compare the adaptation of porcelain fused-to-metal (PFM) restorations made from Ni-Cr alloy, precious alloy and galvanized forming copings after cementation and to provide a theory guidance for their application.

METHODSThree kinds of crowns (Ni-Cr alloy, precious alloy and galvanized forming) were manufactured and cleaned by ultrasonic vibrate with alcoholic solution for 5 minutes, and cemented on their dies as their order. All the crowns were cemented by polycarboxylate zinc-cement and maintained 10 minutes. After coated in the center of methyl acrylic resins, all the samples were cut vertically along buccolingual direction. The cement thickness of PFM was measured by scanning electron microscope and the data were analyzed by multivariate ANOVA.

RESULTSNo significant difference was found between the cement thickness of precious alloy crown and galvanized forming crown (P>0.05), while both of these two kinds of crown had significant differences in cement thickness with Ni-Cr crown (P<0.05).

CONCLUSIONThe adaptation of precious alloy crown and galvanized forming crown are superior to Ni-Cr crown.

The purpose of this study was to compare the marginal fit of all ceramic crowns prepared from alumina slip casting, which is consistent with the conventional In-ceram system, and those fabricated from alumina tapes which is currently under development in an effort to alleviate complexities involved in the forming procedure of the In-ceram crown core. All ceramic crowns, made of In-ceram(slip casting) and alumina tapes(Doctor blade casting), were prepared with 90degreeand 135degreeshoulder margins. The crowns were cemented with a glass ionomer cement and embeded in epoxy resin. The embedded crowns were sectioned faciolingually and mesiodistally and marginal discrepancies and marginal gaps were measured under the Measurescope MM II. The measurements were analyzed using Wilcoxon rank sum test and Kruskal-Wallis test and the results were as follows: 1. In the case of 90degreeshoulder margin, the combined marginal discrepancies and marginal gaps were 78.3 micrometerm and 44.4 micrometer respectively, for the all ceramic crowns fabricated using the alumina tapes. In comparison, the values were 65 micrometer and 25.5 micrometer for the In-ceram crowns. For the marginal gaps a statistical difference existed (p<0.05) but no significant difference was observed for the marginal discrepancy (p>0.05). 2. In the case of 135degreeshoulder margin, the combined marginal discrepancy and marginal gaps were 82.1 micrometer and 40.2 micrometer respectively, for the all ceramic crowns formed with the tapes. As compared with the marginal discrepancy and gaps of the 90degreeshoulder margin in the fabricated from the alumina tapes, no significant statistical differencies were discerned in both cases (p>0.05). 3. There was no statistically significant difference in the fits among four locations around the margins of the all ceramic crowns fabricated using the alumina tapes. The results obtained in this study showed that the marginal fits of the glass infiltrated alumina cores fabricated from the alumina tapes are slightly higher value than those prepared using the In-ceram but the difference is within a clinically acceptable range.
Aluminum Oxide* ; Ceramics ; Crowns ; Glass Ionomer Cements ; Glass*

The purpose of this study was to evaluate the effect of dentin pretreatment with Dentin Conditioner,Ultra-Etch,conditioner of Fuji Plus cement on the shear bond strength of resin-reinforced glass ionomer cements to dentin and analyze the fractured surfaces. To evaluate the bond strengh, the extracted human teeth which had uniform area of exposed dentin were cemented with conventional glass ionomer cement. 3M RelyX TM Luting (Vitremer luting cement). Fuji Plus cement after dentin pretreatment. The shear bond strengh was measured using the Universal testing machine(Instron Co., USA) with a crosshead speed of 1mm/m. The effect of dentin pretreatment was evaluated by observing pretreated dentin surfaces under the scanning electron microscope,measuring the shear bond strength and observing the fractured surfaces under the scanning electron microscope. The results were as follows: On the SEM observation of surface morphology, the specimens treated with Dentin Conditioner, Ultra-Etch and conditioner of Fuji Plus cement were removed the smear layer and funneled dentinal tubules in dentin surfaces. In RelyX TM Luting cement group, shear bond strengh of pretreated group was significantly higher than control group. In Fuji Plus cement group and Fuji I group, regardless of the type of pretreatment agents, there was tendency of increase in the shear bond strength. On the SEM observation of fractured surfaces, as the shear bond strength increase, it were shown thicker cement layers and were not shown dentinal tubules. According to these results, it were shown that dentin pretreatment have much effect on bonding states.
Dentin* ; Glass Ionomer Cements* ; Glass* ; Humans ; Smear Layer ; Tooth

If the bond strength is sufficient to resist orthodontic force, orthodontic brackets can be bonded to restorations. Orthodontic brackets were bonded to composite resin and glass ionomer cement restorations wtih no-mix adhesive or glass ionomer cement. The shear bond strength of adhesives bonded to restorations was studied in vitro. Orthodontic brackets were bonded to 10 extracted natural teeth, 40 composite resin restorations and 40 glass ionomer restorations. The surfaces of composite resin restorations were roughened or applied with bonding agent (Scothbond) after surface roughening. The surfaces of glass ionomer cement restorations were conditioned with acid etching or applied with Scotchbond to etched surface. The adhesive was no-mix resin or glass ionomer cement. The shear bond strength was measured. The results were as follows: 1. Orthodontic brackets could be bonded to composite resin restorations effectively as they could be bonded to acid etched enamel with no-mix adhesive. The shear bond strength was sufficient to resist orthodontic force and was not affected by bonding agent greatly. 2. The shear bond strength of no-mix adhesive bonded to acid etched glass ionomer cement restorations was sufficient to resist orthodontic force. However, the fracture risk of glass ionomer cement restorations was increased during debonding. The bonding agent couldn't increase the shear bond strength greatly. 3. The shear bond strength of glass ionomer cement bonded to glass ionomer cement restorations was lower than that of no-mix adhesive. The shear bond strength was sufficient to resist orthodontic force and was greatly decreased by bonding agent. 4. The shear bond strength of glass ionomer cement bonded to composite resin restorations was too low to resist orthodontic force.
Adhesives* ; Dental Enamel ; Glass Ionomer Cements* ; Glass* ; Orthodontic Brackets ; Tooth

This study was conducted to evaluate the tensile bond strength of three commercially available glass ionomer cements as orthodontic bracket adhesives. 120 premolars extracted for orthodontic treatment were prepared for bonding and standard edgewise brackets were bonded with Shofu GlasIonomer Cement (Shofu Co., U.S.A.), GC Fuji I(GC Co., Japan), KETAC-CEM(ESPE Co., West Germany) with different P/L ratio. The tensile bond strength was tested by Instron testing device after 24hours and 3months from bonding. After debracketing, bracket bases were examined to determine the failure sites. The results of this study were as follows: 1. KETAC-CEM showed the highest bond strength other than measurement after 24 hours and at its original P/L ratio, and seemed to have clinically a proper bond strength. It seemed, however, that both Shofu GlasIonomer Cement and GC Fuji I had an inappropriate bond strength. 2. The incorporation of additional powder into the mixture improved the tensile bond strength. 3. Prolonged storage time improved the tensile bond strength. 4. Of the failure, failure occured at the tooth-adhesive interface(54.2%) was the most common type. The second type of failure(36.7%) was combination type, where part of the adhesive remained on the tooth and part on the bracket. And the last type of failure(9.1%) occured at the adhesive-bracket interface.
Adhesives ; Bicuspid ; Glass Ionomer Cements* ; Glass* ; Orthodontic Brackets ; Tooth

The purposes of this study were to evaluate applicability of resin modified glass ionomer cements and to determine the effect of salivary contamination on the tensile bond strength. Fourty extracted human permanent premolars were prepared for bonding and standard edgewise brackets were bonded with Ortho-One, Fuji Ortho LC, Vitremer and Advance. Fourty extracted human permanent premolars were contaminated with saliva, dried and bonded with same materials above. The tensile bond strength was tested by Instron testing device after storage in normal saline at 37degrees C for 24 hours from bonding. The results were as follow : 1. The tensile bond strength of Ortho-one group was 7.68 1.76, Advance group was 7.87 2.80, Fuji Ortho LC group was 4.99 +/-2.53, Vitremer group was 2.80 0.88 MPa. The tensile bond strength in contaminated condition of Ortho-One group was 4.12 1.67, Advance group was 5.37 0.68, Fuji Ortho LC group was 4.41 1.61, Vitremer group was 2.60 1.10 MPa.. 2. Salivary contamination did not affect the tensile bond strength when compared with the uncontaminated enamel group in Fuji Ortho LC and Vitremer (p>0.05) and there was great significant difference in the tensile bond strength of Ortho-One and Advance. 3. Advance, Ortho-One and Fuji Ortho LC seemed to have clinically a proper bond strength.
Bicuspid ; Dental Enamel ; Glass Ionomer Cements* ; Glass* ; Humans ; Saliva