Are human teeth only diphyodont or both diphyodont and monodont?
The definitions from the Oxford Dictionary of Dentistry:

Diphyodont


  Describing the development of two successive dentitions, one primary
  and another secondary (permanent), as found in most mammals including
  humans.


Monophyodont


  Possessing only one generation of teeth. It is a characteristic of
  some mammals, including the manatee, seal, and walrus.


As you can see, the term diphyodont is generally not used to refer to the individual teeth, but rather to the whole animal (i.e. the sets of teeth). A monophyodont is an animal that has only one set of teeth.