Green’s Dictionary of Slang

kindheart n.

a dentist.

1614		Jonson Bartholomew Fair Induction: He has ne’er a sword-and-buckler man [...] nor a Kindheart, if anybody’s teeth should chance to ache in his play.
c.1625		Rowley Woman never Vext I i: Mistake me not, kindheart. He calls you tooth-drawer.