[Surface roughness and staining stability of infiltrant resin for enamel white spot lesion]

To investigate the influence factors on the surface roughness and staining susceptibility of infiltrant resin.

In the study, 30 human third molars were used, and each sample had three open enamel windows. The samples were randomly divided into three groups according to their different demineralized time. Each sample had at least one intact spot (A), one infiltrant resin spot (B) and one artificial white spot lesion (C). The surface roughness was tested before color staining for all the three spots of each specimen. The specimens were stored in a staining solution (coffee) for a period of 21 days, before and after which the color Commission Internationaled' Eclairage (CIE)L*a*b* was recorded for A, B and C spots.

The B spot's surface roughness of each group was(0.15 ± 0.02)μm,(0.31 ± 0.03)μm and(0.40 ± 0.02)μm, respectively. And the C spot's surface roughness each was (1.08 ± 0.10)μm,(2.89 ± 0.13)μm and(3.41 ± 0.14)μm. The surface roughness of B and C of the three groups increased with demineralization time longer, and had significant difference for both B and C (P < 0.01). The ΔE of the three groups between A and B before staining had significant difference (P < 0.01). And the ΔE of group1 was less than 3.7, but the other two groups' more than 3.7. After staining, the ΔE of groups 1 and 2 was less than 3.7 but that of group 3 was more than 3.7. There were significant differences between groups 1 and 3, and also between groups 2 and 3(P < 0.01).

The degree of the lesion's demineralization has effect on the surface roughness and color susceptibility of infiltrant resin. The increased surface roughness of infiltrant resin has positive effect on masking enamel white spots.