Dentin micro-architecture using harmonic generation microscopy.

OBJECTIVES: We present a novel way to create high-resolution three-dimensional images of tooth dentin by harmonic generation scanning laser microscopy.
METHODS: The images were taken using a pulsed infrared laser. Three-dimensional reconstruction enables the visualization of individual tubules and the collagen fibrils mesh around them with an optical resolution of approximately 1 microm.
RESULTS: The images show micro-morphological details of the dentinal tubules as well as the collagen fibrils at a depth of up to about 200 microm. The data show that while collagen fibrils are organized in planes perpendicular to the tubules, close to the dentin enamel junction they lie also along the long axis of the tubules.
CONCLUSIONS: The unique 3D information opens the opportunity to study the collagen fibril arrangement in relation to the tubule orientation within the dentin matrix, and may be applied to study the micro-morphology of normal versus altered dentin.