endodontic R-type files

[tafatefo]

Advertisement - Members don't see this ad

I was asked a detailed research on a historical type of endodontic files known as R-type files. and till now i can't find any source which can help me on the net.
can any one here tell me about the R-type files or tell me where can I find notes about it on the net??
THANX alot 🙂