Dental Enamel is the hardest mineralized tissue in the human body which is comprised of nanorod-like hydroxyapatite crystals arranged into a highly organized micro-architectural unit called an enamel prism. In this paper the direct growth of human enamel-like structures on human tooth using fluorapatite/phosphoric acid pastes is explored. SEM images show that the newly formed calcium phosphate crystals can be self-assembled into a similar ordered microstructure as those seen in human enamel. The mechanism of how these structures form is discussed. This work demonstrates the potential of applying nanotechnology to regenerate dental enamel clinically without cells.