Detection of root canals is vital for dental diagnosis, however it is difficult to locate these anatomies within sub-millimeter dimension. To determine the ability of MRI to display such structures, a bovine tooth with different sized artificial cavities was prepared. It was evaluated with a preclinical 7T system and a clinical 3T MR system against cone beam CT. 7T measurements with UTE offer precise distinction of cavities up to 200µm. 3T UTE allows only differentiation of 1000µm cavities due to blurring. Tooth immersed in contrast agent solution allows localization up to 200µm cavity with spin echo sequence and negative contrast.