| Objective The commonly used wall buildup preparation material,glass ionomer cement(GIC),is close to the color of the natural tooth tissue,which may cause excessive removal of the tooth tissue during the process of removing the buildup.By adding methylene blue,crystal violet,and erythrosine organic dye solution to the glass ionomer cement material,the glass ionomer cement can have a distinct color and could be distinguished from the tooth tissue.Therefore,the difficulty of dismantling the buildup was reduced.The purpose of this study was to investigate the setting time,surface topography,mechanical properties,bonding properties,physical and chemical properties,antibacterial properties of the color-modified glass ionomer cement and observe the effects of three organic dyes on the various parameters of glass ionomer cement,which provides theoretical basis for the clinical application of the color-modified wall buildup material.Methods 1.Effect of adding organic dyes on setting time of GICMethylene blue,crystal violet,and erythrosine solution were prepared at a concentration of 1% and 2%,respectively.And 1?L of the dye solution and 100 ?L of the GIC solution were thoroughly mixed,and then 0.3 g of the GIC powder was added in proportion.After spatulation,the material was pressed into a tetrafluoroethylene mold(inner diameter: 10 mm,height: 2 mm).The setting time of GIC material was tested with reference to the dental water-based cement industry standard.2.Effect of adding organic dyes on surface topography of GIC(1)Macroscopic topography: Observing the visual color change of GIC after adding the organic dye solution.(2)Microscopic topography: Scanning electron microscopy(SEM)was used to observe the microscopic surface morphology of GIC after setting.3.Effect of adding organic dyes on mechanical properties of GIC(1)Mixing the methylene blue,crystal violet,erythrosine dye solution with GIC liquid agent uniformly and then spatulating according to the water/powder ratio.Subsequently,the material was pressed into the tetrafluoroethylene mold(inner diameter :4mm height: 6mm).The bottom surface of the cylindrical mold is covered by the transparent plastic film.The specimens were demold after setting and immersed in artificial saliva at 37 °C for 1 d,7 d.(2)Place the specimens on loading test bench of the Instron universal tester.Stress was loaded through test piece(loading speed 0.75 mm/min),recording the maximum stress value of the specimens when fracture occurred and calculate the compressive strength according to the formula.4.Effect of adding organic dyes on the bonding properties of GIC(1)Shear bond strength: According to the inclusive criteria,84 premolars which removed by orthodontic extraction were selected.The entire enamel layers were removed by low-speed plate grinder and the dentin layers were exposed.The roots were embedded in a square tetrafluoroethylene mold to expose the crown.The 320#,400#,and 600# emery sandpaper are sequentially used to polish the dentin surface.The methylene blue,crystal violet,erythrosine dye solution and GIC liquid are fully prepared as described above.After spatulation,the materials were filled into a mold(inner diameter: 4 mm height: 2 mm)and bonded to the dentin surface.The specimens were immersed in artificial saliva at 37 °C,and were taken out after 1 d and 7 d,respectively.The shear stress was loaded by Instron universal tester until the specimens fell off.The maximum stress value was recorded when failure of the bonding interface happened and the shear bond strength was calculated.(2)Fracture mode: Using the operative microscope to magnify the bond interface 25 times to observe the fracture interface,analyze the fracture mode.Classifying the fracture mode according to the following criteria: 1.adhesive failure: fracture occurs at the bonding interface 2.Cohesive failure: fracture occurs inside the GIC 3.Mixed failure: bond failure and cohesive failure exist simultaneously.5.Effect of adding Organic Dyes on Water Absorption and solubility Value of GICThe color-modified GIC was prepared in the identical method as described above and pressed into a tetrafluoroethylene mold(inner diameter: 6 mm,height: 3 mm).The specimens were stored in an incubator at 37 ° C and the weight change was measured using a Paffenbarger gravimetric method to calculate water absorption and solubility value of specimens in each group.6.Effect of adding organic dyes on the antibacterial effect of GICThe color-modified GIC was prepared,pressed into a Polymethylmethacrylate mold(inner diameter: 10 mm,height: 1 mm),and the Streptococcus mutans was inoculated on the surface of the specimens to establish a single-species biofilm model.The antibacterial properties were measured by a film-sticking method,and the inhibition rate was calculated.Live/dead staining was performed using CFSE and PI fluorescent dye solution and the S.mutans biofilm(24h-old)was visualized by confocal laser scanning microscope to calculate the red/green fluorescence ratio.Result 1.Effect of adding organic dyes on setting time of GICThe setting time of GIC materials after adding 1%,2% methylene blue,crystal violet and erythrosine dye solution was not prolonged or shortened,and there was no significant difference between the groups(P > 0.05).2.Effect of adding organic dyes on the surface topography of GIC(1)Macroscopic topography: It can be observed that the GIC has distinct color compared with the control group after adding methylene blue,crystal violet and erythrosine dye solution at the concentration of 1% and 2%.The surface of each samples is smooth and flat without obvious cracks and bubbles.(2)Microscopic topography: There was no significant difference in the surface microstructure between the color-modified GIC and the control GIC under the scanning electron microscope.The uneven granular structure is visible which is different from the smooth surface of the macroscopic morphology.The circular pores of different sizes and irregular cracks of different sizes are scattered.3.Effect of adding organic dyes on the compressive strength of GICWith the prolongation of soaking time in artificial saliva,the compressive strength of each group of GIC specimens after 7 d was significantly lower than that of 1 d(P < 0.05).There was no significant difference in the compressive strength at 1 and 7d between the color-modified GIC groups and control group(P > 0.05).4.Effect of adding organic dyes on the bonding properties of GIC(1)The shear bond strength of each color-modified group was significantly higher than that of the control group when the specimens were immerged for 1d(P < 0.05).After immerged in artificial saliva for 7 d,the shear bond strength of the control group increased and there was no statistically significant difference between the groups(P > 0.05).(2)The fracture modes of each group were mainly cohesive failure and mixed failure mode.No single adhesive failure mode was observed,and there was no statistical difference between the groups(P > 0.05).5.Effect of adding organic dyes on water absorption and solubility values of GICAfter 7 d of immersion in artificial saliva,there was no significant difference in water absorption value between the color-modified groups and the control group(P > 0.05),and the solubility value of each color-modified GIC group was significantly higher than that of the control group(P < 0.05).No Significant difference was observed between the color-modified GIC groups(P > 0.05),in which 1% methylene blue GIC group has the highest solubility value.6.Effect of adding organic dye on the antibacterial effect of GICThere was no significant difference in CFU between the color-modified GIC groups and control group(P > 0.05).The inhibition rate of the groups at 2% concentration was slightly higher than that of the groups at 1% concentration.Conclusion 1.The three types of organic dyes including methylene blue,crystal violet and erythrosine have obvious effects of color modification on GIC.2.The addition of organic dyes has no significant effect on GIC setting time,microscopic surface topography,compressive strength,water absorption value and antibacterial effect.3.The shear bond strength of the GIC with addition of organic dyes is higher than that of the GIC without the addition of organic dye during the initial stage,and the solubility value of the GIC increases after adding the organic dye solution. |
PDF Full Text Request