Mechanism of enamel dissolution and its prevention.

In this paper the mechanism of dental enamel dissolution is discussed. Special attention is given to the anisotropic solubility behaviour (hollow tube formation) of demineralized enamel crystallites. The combined evidence strongly indicates that this peculiar dissolution behaviour is caused by dislocations. The dislocations--linear lattice defects--are present in the crystallite center and are the cause of two active dissolution sites in each crystallite. Initial as well as later stages in the caries process are discussed. Experimental evidence is presented which indicates that the active sites can be inactivated by agents like EHDP and MFP. After inactivation, acid penetration is either prevented or strongly retarded.