Optical coherence tomography is a new method for noninvasively imaging inte
rnal tooth and soft tissue microstructure. The intensity of backscattered l
ight is measured as a function of depth in the tissue. Low coherence interf
erometry is used to selectively remove the component of backscattered signa
l that has undergone multiple scattering events, resulting in very high res
olution images (< 15 mum). Lateral scanning of the probe beam across the bi
ological tissue is then used to generate a 2-D intensity plot, similar to u
ltrasound images. This imaging method provides information that is currentl
y unobtainable by any other means, making possible such diverse application
s as diagnosis of periodontal disease, caries detection, and evaluation of
restoration integrity. This chapter presents an overview of this exciting n
ew imaging technique and its current application to dental diagnosis. Copyr
ight (C) 2000 S. Karger AG, Basel.