The answer is yes and no. 

 If you want to actually land a shark, yes.  My standard set up for small sharks (up to 4-5') is .... 5-6' fluoro leader 40# attached to main line with uni-uni then 12-18" wire leader attached to fluoro with a swivel.  The wire protects from the teeth, the fluoro protect from skin, fins, tail as fish run.

If your fishing for species like snook, reds, tarpon.... they will generally see the wire and avoid the bite.