Histological observations of dental tissues using the confocal laser scanning microscope

To investigate the time course of mineralization in undecalcified dental tissues, calcein- and tetracycline-labeled rat maxillary molar sections were stained with Villanueva bone stain en bloc, embedded in methyl-methacrylate (MMA), ground to 50 microns thickness, and observed by confocal laser scanning microscopy (CLSM). This method allowed observation of dental structures including odontoblasts, pulp cells and periodontal ligament, and dentinal tubules and enamel rods at high resolution; labeled enamel, dentine, and cementum could be observed simultaneously regardless of section thickness. CLSM permitted simultaneous observation of both the components of calcified tissue and the cellular components of dental tissues, and assessment of the mineralization time course of hard tissues labeled by tetracycline or calcein. The technique is useful for both assessing the elements composing dental structure and observing the histological dynamics by which dental structure develops.