Here's is what I am talking about;
Bear with me, I might be on to something, and I might not.
I believe they are Endodontic drills (or files, reamers, broaches, etc) used for Root canals
This makes sense because the Borden Connector and the Dental expander are also orthodontic tools.
look at these pics of some modern ones
as you can see above, they have different sizes with corresponding numbers on them
and here is one in a tooth for scale;
this one has the numbers on the head (like on the helmet) and also has the vertical lines as opposed to the horizontal
And look at this one!!!