MECHANISM FOR DENTAL-CARIES BASED ON CHEMICAL PROCESSES AND DIFFUSION PHENOMENA DURING INVITRO CARIES SIMULATION ON HUMAN TOOTH ENAMEL

Artificial carious lesions were produced in a range of lactate buffers containing disodium-methane-hydroxy-diphosphonate and the depths of the lesions were measured. The depth of the body of the lesion depended on the calculated concentration of un-ionized lactic acid (HL), and the innermost boundary depended on HL concn. and pH. Apparent diffusion coefficients of the order 10-10cm2/s were calculated from the boundary movement. A mechanism is proposed for the caries process. Diffusion, predominantly of the un-ionized chemical species HL, H3PO4, CaHPO4, Ca(H2PO4)2 and CaL2 occurs through the intercrystalline and interprismatic pores of enamel filled with water and protein. Dissolution takes place throughout the lesion by H+ and L- as HL dissociates. The outer enamel surface is partly protected by reversible adsorption of suitable chemical species. © 1979.