Granted Patent
Utility
US 5,286,423 · App. 07/889,828
Method of heat treating gutta percha based material to improve the characteristics thereof
Inventor:
William B. Johnson
Patented Case
View Patent ↗
Granted: Feb 15, 1994
Filed: May 29, 1992
Inventor
William B. Johnson
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.