Root and pulpal dentin after surface demineralization

Abstract Previous studies have indicated that there may be a difference in connective tissue response to surface demineralized dentin from root and pulpal surface regions. Consequently, it was the purpose of the present investigation to examine the initial surface characteristics of the dentin from these regions to determine if there were differences which could enhance interactions with adjacent connective tissues. Rectangular dentin specimens with opposite faces of root and pulpal region dentin were immersed in a saturated solution of citric acid, pH 1, for 3 min, rinsed, and prepared for examination in an ISI-40 SEM. Comparisons were made between root and pulpal surfaces of the specimens, and with non-acid treated controls. Control specimens were characterized by the presence of a smear layer which obscured the openings of dentinal tubules on all surfaces. Citric acid treatment removed the smear layer, resulted in exposure of dentinal tubule orifices, and produced a mat-like, fibrillar surface texture. The pulpal surface had a more coarse appearance than the root surface. Quantitation of the number and diameter of tubule orifices showed larger values for the pulpal surface. The percentage of die surface area occupied by tubule orifices was significantly greater on the pulpal aspect. It was concluded that surface demineralization of dentin from the pulpal region results in exposure of a greater amount of collagen substrate, and the latter may predestine an enhanced interaction with connective tissue components.