The Collaborative International Dictionary of English v.0.48:

Dentistry \Den"tist*ry\, n.
   The art or profession of a dentist; dental surgery.
   [1913 Webster]

WordNet (r) 3.0 (2006):

dentistry
    n 1: the branch of medicine dealing with the anatomy and
         development and diseases of the teeth [syn: dentistry,
         dental medicine, odontology]