Immunolocalization of the small proteoglycan decorin in human teeth.

The immunolocalization of decorin was studied by confocal laser scanning microscopy and transmission electron microscopy. In the apical area of developing teeth, labelling for decorin was found in the dental papilla cells, prodontoblasts and also in the Hertwig's epithelial cells. Mantle dentine and the initial predentine were negative. In circumpulpal dentine, intense reactivity extended along the calcification front and dentinal tubules. Fluorescence was also evident in odontoblast cell bodies and their processes in predentine. None was perceived, however, in the predentinal matrix. Faint staining was observed on the calcified dentinal matrix. Immunoelectron microscopy revealed staining for decorin in collagen fibrils lining the predentine-dentine junction, and where arrays of labelled filaments were noted orthogonal to the collagen fibrils. Staining extending from the calcification front was observed in the matrix adjacent to the dentinal tubule. The decorin observed at the calcification front might regulate the mineralization of dentinal matrix.