Granted Patent
Utility
US 4,836,780 · App. 06/899,419
Anti-curvature dental root canal shaping file
Inventor:
L. Stephen Buchanan
Patented Case
View Patent ↗
Granted: Jun 6, 1989
Filed: Aug 22, 1986
Inventor
L. Stephen Buchanan
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.