Surface Microhardness, Masking, and Color Stability of white Spot Lesions Infiltrated by Icon versus an Experimental Resin Containing MA-POSS Nanoparticles

This study compared the efficacy of an experimental resin containing polyhedral oligomeric silsesquioxane (POSS) nanoparticles with methacrylate groups (MA-POSS) versus the Icon resin regarding the masking, color stability, and microhardness of artificially induced white spot lesions (WSLs).  

In this in vitro study, 60 bovine enamel specimens were assigned to two groups for assessment of color (group C) and surface microhardness (group H). white spot lesions were induced on the specimens using demineralizing and remineralizing solutions. Each group was divided into two subgroups for the application of experimental resin and Icon. the color and surface microhardness of specimens were measured, after the induction of WSLs, and after infiltration. Group C samples were immersed in coffee (1 hour/day for one week) and their color was measured again. ANCOVA was used to compare microhardness between the two resin groups. To compare the masking and staining of infiltrated lesions, ΔE, ΔL and L* values after infiltration and staining were compared with the values after the induction of WSLs using independent t-test and repeated measures ANCOVA (α=0.05). 

Microhardness analysis by ANCOVA revealed no significant difference between the groups following resin infiltration (P=0.144). The performance of the two resins after infiltration (P=0.75 for ΔE, P=0.20 for ΔL, P=0.57 for L*) and after staining (P=0.31 for ΔE, P=0.07 for ΔL, P=0.32 for L*) was not significantly different.

The experimental resin was comparable to Icon with the main advantage of easier availability in Iran.