P. Anderson et Jc. Elliott, Rates of mineral loss in human enamel during in vitro demineralization perpendicular and parallel to the natural surface, CARIES RES, 34(1), 2000, pp. 33-40
Human enamel is a structurally anisotropic material. The aim of this study
was to investigate whether this structural anisotropy is reflected in the d
emineralization behaviour of enamel. Kinetics of demineralization of in vit
ro caries lesions with the direction of acid attack perpendicular to the na
tural surface of dental enamel from human premolar teeth were compared with
kinetics when demineralized parallel to this surface, Pairs of enamel samp
les from the same tooth were demineralized under identical conditions, Loss
of mineral with time was very nearly linear for both directions (consisten
t with the rate-controlling step being reaction at the advancing front rath
er than transport processes), but the perpendicular rate was, on average, a
bout 14% higher than the parallel rate. The rate of demineralization parall
el to the surface increased from the natural surface to the enamel-dentine
junction by 10-25%, depending on sample. The origin of fine structure and s
light departures from linearity in the loss of mineral with time plots are
discussed. Mineral masses per unit area were determined from absorption of
a 15-mu m diameter X-ray beam using photon (AgK alpha) counting methods. Co
pyright (C) 2000 S. Karger AG, Basel.