IADR Abstract Archives
Effect of Etching Methods on Bond Strength Of Caries-infitrated Enamel
Objectives: The aim was to determine the influence of caries infiltrant application on the shear bond strength of different etching methods on sound and demineralized enamel.
Methods: 180 extracted human upper incisor’s enamel surfaces were used in the study. Half of the specimens were artificially demineralized(14 days, acidic buffer, pH 4.8), other half was remained sound. Sound and demineralized samples(n=90) were divided first into 2-subgroups(n=45): Caries infiltrated group(Icon, DMG)(CI) and no caries infiltrated group(NCI). Than, these groups were also divided into three according to the etching procedures(n:15): 35% phosphoric Acid(PA), %9 hydrofluoric Acid(HFA), Er,Cr:YSGG laser(LA). The caries infiltrant applicated groups were thermocycled(5000X, 5°-55°C) before etching procedures. Following different etching procedures, a nanohybrid composite(Filtek Z250, 3M ESPE) was applied on enamel surfaces by using an etch-and-rinse adhesive system(Adper Single Bond-2, 3M ESPE). All specimens were analyzed after thermocycling on a shear bond strength testing machine at a crosshead speed of 1mm/min. The values were recorded at the time of failure of composite resins. The failed samples were examined under a stereomicroscope at X20 magnification to determine the mode of failure. The data were statistically analyzed by three-way Anova and multiple comparisons were made by Bonferroni test at 5% significance level.
Results: In CI groups; PA showed significantly higher shear bond strength value than other etching groups both in sound and demineralized enamel(p<0,05), but LA showed higher bond strength than HFA in sound enamel(p<0,05), while it had similar value with HFA in demineralized group(p>0,05). In NCI groups; LA and HFA showed similar values in both sound and demineralized enamel(p>0,05), but PA showed higher bond strength value than other groups in sound enamel(p<0,05), and similar value with LA(p>0,05) and higher value than HFA(p<0,05) in demineralized enamel.
Conclusions: 35% phosphoric acid can be used on caries infiltrated enamel without impairing the bond strength.
Methods: 180 extracted human upper incisor’s enamel surfaces were used in the study. Half of the specimens were artificially demineralized(14 days, acidic buffer, pH 4.8), other half was remained sound. Sound and demineralized samples(n=90) were divided first into 2-subgroups(n=45): Caries infiltrated group(Icon, DMG)(CI) and no caries infiltrated group(NCI). Than, these groups were also divided into three according to the etching procedures(n:15): 35% phosphoric Acid(PA), %9 hydrofluoric Acid(HFA), Er,Cr:YSGG laser(LA). The caries infiltrant applicated groups were thermocycled(5000X, 5°-55°C) before etching procedures. Following different etching procedures, a nanohybrid composite(Filtek Z250, 3M ESPE) was applied on enamel surfaces by using an etch-and-rinse adhesive system(Adper Single Bond-2, 3M ESPE). All specimens were analyzed after thermocycling on a shear bond strength testing machine at a crosshead speed of 1mm/min. The values were recorded at the time of failure of composite resins. The failed samples were examined under a stereomicroscope at X20 magnification to determine the mode of failure. The data were statistically analyzed by three-way Anova and multiple comparisons were made by Bonferroni test at 5% significance level.
Results: In CI groups; PA showed significantly higher shear bond strength value than other etching groups both in sound and demineralized enamel(p<0,05), but LA showed higher bond strength than HFA in sound enamel(p<0,05), while it had similar value with HFA in demineralized group(p>0,05). In NCI groups; LA and HFA showed similar values in both sound and demineralized enamel(p>0,05), but PA showed higher bond strength value than other groups in sound enamel(p<0,05), and similar value with LA(p>0,05) and higher value than HFA(p<0,05) in demineralized enamel.
Conclusions: 35% phosphoric acid can be used on caries infiltrated enamel without impairing the bond strength.