No, Smoothing is smoothing. It averages the distance between vertices on the mesh - as in ZBrush or Mudbox, etc.  it doesn't add any additional geometry as subdivding would.

 

Les, I don't know what figure you're doing this with but you should try using the OBJ from the Runtime and NOT an exported obj.  While the majority of Poser figures are not welded, many of the figures from Smith Micro are. You can load an OBJ of Miki3 for example directly from your Runtime and it should stay solid as you apply your smooth brush. It should even stay welded as you subdivide (if you need to for some reason).  For models with breaks  in the base OBJ, you'll need something like Poser Morph Loader from Colorcurvature for now.