Aim: To determine the changes in Ca2+ release before and after the application of Riva Star, AgNO3 and to analyse the changes in surface roughness of the samples.

Methods: The Riva Star, AgNO3 were used to measure their effects on the demineralisation processes of the windowed human enamel in 50ml pH4.0 acetic solution under 370C. The sound human enamel samples were sliced and varnished using nail polish and 5mm² was left on the surface of enamel sample in order to make windowed-type enamel. The demineralised enamel samples were treated by these agents after 4hours of demineralisation, and later put back into the same acetic acid solutions for further 4hours of demineralisation to detect the changes.  

Results: The results demonstrated that Riva Star (SDF/KI) treatment exerted the inhibition ability in demineralisation remarkably. However, when the silver nitrate was applied alone, it slightly accelerated the demineralisation firstly and then followed a straight line. The treatment of silver nitrate alone also caused black staining. Reducing agent such as potassium iodide following the treatment of silver nitrate can inhibit the demineralisation instantly without causing the initial acceleration in demineralisation and the final black staining.

Conclusions: Riva Star (SDF/KI) is an effective demineralisation inhibition agent for up to 48 hours following the topical application. The potassium iodide application following the treatment of silver nitrate can not only accelerate the inhibition performance, but also effectively avoid black staining.

Keywords: Silver ions, Demineralization, Caries, Riva Star, SDF, Surface roughness