Figure 2.

Schematic illustration of the process of dentin dissolution by bacterial acids. Under resting conditions (pH 7.0) both the mineral and organic matrix (containing inactive MMPs, green dots) are intact (a). Upon a cariogenic challenge (pH 5.0), the apatite is dissolved thus exposing the organic matrix to degradation by salivary and dentin MMPs (green dots represent MMPs) (b). The low pH also activates MMPs, which are represented as red dots (c). The subsequent neutralization by salivary buffer systems enhances the degrading activity of the organic matrix by MMPs (d)¹⁰⁰