Investigation of Biodentine as dentine replacement material.

OBJECTIVE: Biodentine was compared to glass ionomer and resin modified cements in an "open sandwich" restoration.
METHODS: Fuji IX, Vitrebond and Biodentine were characterised using various techniques. The effect of etching with 35% phosphoric acid was investigated by assessment of surface topography, Fourier transform infrared (FT-IR) spectroscopy, surface micro-hardness and micro-leakage using tagged carboxylated-modified fluorescent microspheres and tracing the presence of these particles with a confocal microscope.
RESULTS: Acid etching resulted in erosion of the material surface with exposure of the glass particles in the glass ionomer-based materials. Biodentine exhibited a reduction in the chlorine peak and the calcium-silicon ratio. There was no difference in the micro-hardness in etched and un-etched materials. The FT-IR plots did not show any chemical changes caused by etching for all the materials investigated. Both Vitrebond and Fuji IX exhibited no leakage at the dentine to material interface while Biodentine exhibited leakage both when it was etched and also when the surface was left unprepared. The sandwich technique was effective and prevented micro-leakage with glass ionomer-based materials but micro-leakage occurred with Biodentine.
CONCLUSIONS: Biodentine demonstrated both structural and chemical changes when etched with 37% phosphoric acid. Biodentine exhibited a lower calcium to silicon ratio and a reduction in the chloride peak height when etched. When used as a dentine replacement material in the sandwich technique overlayed with composite, significant leakage occurred at the dentine to material interface. On the other hand materials based on glass ionomer cement were etched successfully and no chemical and physical changes or micro-leakage were detected when the materials were used as bases under composite restorations. The micro-hardness of all the materials was unaffected by etching.