Effects of bleaching agents on the surface properties of calcium silicate-based cements

To evaluate surface properties of three calcium silicate-based cements (CSCs) after exposure to bleaching agents.

80 samples of each CSC (Biodentine, MTA Angelus, and MTA Repair HP) were prepared and allocated into four groups (n = 20): three groups were exposed to bleaching agents (sodium perborate, carbamide peroxide, and hydrogen peroxide) three times at 4-day intervals and one control group. The surface microhardness, indentation depth (n=10) and surface roughness (n=10) were measured. The surface morphology and elemental composition was examined using scanning electron microscope-energy dispersive spectroscopy analysis.

All bleaching agents induced morphological alterations and affected elemental distribution. Both hydrogen peroxide and carbamide peroxide significantly reduced the microhardness of all CSCs, with hydrogen peroxide causing significantly greater reduction than carbamide peroxide. Both hydrogen peroxide and carbamide peroxide significantly increased indentation depth of all CSCs, with hydrogen peroxide causing a significantly greater increase than carbamide peroxide. All bleaching agents caused a significant increase in surface roughness of all CSCs, with hydrogen peroxide causing the highest increase, followed by carbamide peroxide and sodium perborate. In all groups, Biodentine exhibited lower roughness, lower indentation depth, and higher microhardness compared to MTA Angelus and MTA Repair HP.

The findings suggest that Biodentine exhibited more favorable surface properties compared to MTA Angelus and MTA Repair HP after exposure to bleaching agents, while sodium perborate caused fewer adverse effects than carbamide peroxide and hydrogen peroxide. The choice of CSC and bleaching agent may influence the long-term stability of cervical barriers.