The earliest reference to tooth decay and toothache came from the ancient Sumerian text known as the Legend of the worm . Dental caries is an infectious microbiologic disease of the teeth that results in localized dissolution and destruction of calcified tissues or it is a microbial disease of the calcified tissues of the teeth, characterized by demineralization of the inorganic portion and destruction of the organic substance of the tooth. Progression of caries in dentin is different from progression in the overlying enamel because of the structural differences of dentin. Dentin contains...