Effect Of Infiltration Resin On The Microhardness Of Artificial Caries Lesions

Objective: To analysis the effect of artificial caries’ s micro-hardness immediately and after the twice demineralization through coating resin infiltration, fluoride varnish and fissure sealant.Methods: Forty cow incised enamel samples were used, made artificial caries lesions in the demineralization liquid. The specimens were randomly divided into four groups(A,B,C,D), handled the samples with resin infiltration(group A), fluoride varnish(group B),fissure sealant(group C) respectively, group D was the control. The samples were sectioned perpendicularly to the surface through the centre. One half of each sample was measured surface and cross-sectional micro-hardness. The other half put in demineralization liquid for fourteen days, then measured surface and cross-sectional hardness. All data were analyzed statically with the software SPSS21.0, statistical description used`X±S, data between groups by Variance analysis, further pair-wise comparison used SNK test.Results: Handled the samples with infiltration, fluoride varnish, fissure sealant respectively, the surface micro-hardness values were 355.31 ±30.58,346.08±23.88,341.79±16.62 respectively, and there were no statistical difference between the three groups, but the differences existed in group D(299.73±23.35).At the 40μm level, the results of four groups(A,B,C,D) were 339.98±33.26, 328.19±14.85, 330.34±20.08, 302.23± 28.73.There were no difference between group A,B and C, but different from group D. At the 80μm level, the results of four groups(A,B,C,D) were 324.19±16.62,302.62±13.36, 315.60±19.71, 293.93± 23.02. There were significant difference between group A, B, D, as well as C, D. At the 120μm level, the results of four groups(A,B,C,D) were 322.99±10.86, 291.21±10.19, 296.86±14.34, 287.60±14.51. There were significant difference between group A and B, C, D, and the others had no difference. After the other half samples demineralized, the surface microhardness values of four groups(A,B,C,D) were 314.58±21.44, 302.50±16.14,300.13±14.96, 261.89±24.31.No significant difference between group A,B and C, there were significant difference comparing with group D, and the value of group A was higher than other groups. At the 40μm level, the results of four groups(A,B,C,D)were 293.75±22.63, 259.54±21.07, 272.86±19.63, 244.79± 31.99.There were significant difference between group A, B, D, as well as C, D. At the 80μm level, the results of four groups(A,B,C,D)were 271.07±18.36, 236.74±16.29, 238.27±24.09, 224.33±28.73.There were no significant difference between group B and C,D, but different from group A. At the 120μm level, the results of four groups(A,B,C,D) were 250.84±18.20,216.82±11.39,217.33±16.72, 212.80±25.67. There were significant difference between group A and B,C,D, and the others had no difference.Conclusion: Resin infiltration penetrated into artificial caries effectively, filling pores and increasing the intensity of enamel.