A dent on the vamp of stan smith shoes

I don't know what a shoe vamp is, but you might take a look as some shoe stretchers. Some have little insert-able bumps that might match the vamp.

Get a shoe-tree. Place that inside the footwear for a week and the shoe should return to dentless.

If financing is a problem, shove newspapers or socks into the front of the footwear.

...for those still wondering, a vamp in footwear refers to the top part of the shoe/sneaker at the front (for area) and the center (where laces, buckles or Velcro would be located on non-loafer shoes or clog-style stuff)