THE INFLUENCE OF THE ORGANIC MATRIX ON DEMINERALIZATION OF BOVINE ROOT DENTIN IN-VITRO

The effect of matrix degradation on the rate of demineralization of de ntin lesions was investigated. It was hypothesized that the deminerali zed matrix would inhibit the demineralization of the underlying minera lized dentin. Bovine root dentin specimens were alternately deminerali zed and incubated with either a bacterial collagenase or buffer (contr ol). The demineralization was carried out under various conditions: Ac etic acid solutions were used to form incipient and advanced erosive l esions, and lactic acid solutions containing a bisphosphonate were use d to form incipient subsurface lesions. Under all conditions, the demi neralization was found to be accelerated when the matrix was degraded by collagenase. This increase was more pronounced in advanced erosive lesions than in incipient lesions. Microscopic examination of collagen ase-treated specimens revealed that the matrix of erosive lesions cont ained several layers of differently affected matrices, whereas the mat rix of subsurface lesions appeared to be equally affected throughout t he lesion. In conclusion, the matrix degradation was different in eros ive and subsurface lesions but promoted the demineralization in both t ypes of lesions.