  Electromechanical imaging of tooth dentin and enamel has been performed with
sub-10 nm resolution using piezoresponse force microscopy. Characteristic
piezoelectric domain size and local protein fiber ordering in dentin have been
determined. The shape of a single collagen fibril in enamel is visualized in
real space and local hysteresis loops are measured. Because of the ubiquitous
presence of piezoelectricity in biological systems, this approach is expected
to find broad application in high-resolution studies of a wide range of
biomaterials.
