INTRODUCTION: Mineral trioxide aggregate (MTA) has shown potential as an endodontic material in several clinical applications, Cetrain inherent disadvatage of the material led to introduction of Biodentin. Retreival of MTA and Biodentin (BD) was challenging to most of the clinicians. OBJECTIVE: To compare and evaluate the effect of Carbonic Acid (CA) on dissolution of MTA, BD and Root Dentin (RD). MATERIALS AND METHODS: Uniform discs of MTA, BD and RD were prepared under standardized condition following manufacturer’s instructions. Preliminary microhardness of all the samples were tested after 24 hours. All samples were soaked in CA for 5 minutes and the microhardness were tested. The results were statistically analyzed using paired sample‘t’test. RESULTS: BD showed no statistically significant difference whereas MTA and RD showed a statistically significant difference in microhardness before and after exposure to CA. CONCLUSIONS: CA can be effectively used as an adjunct to dissolve set MTA. The effect of CA to dissolve BD was minimal. CA has been found to be detrimental to the microhardness of RD.Keywords: Biodentin, Carbonic acid, Microhardness, Mineral trioxide aggregate, Root dentin.