topology mirror issue

I have a mesh that is symmetric on the x axis. It was originally created with a mirror and then applied and unwrapped. There is a large (100+) loop on the x axis, but some of the verts have offset slightly (.002) on x and it’s causing problems with topology mirror in edit mode. How can I get all those loop verts to have 0 for x? I tried selecting the loop, Scale X 0. And it helps but it’s not perfect. Basically like mirror clipping, but without the mirror. Constraint maybe? Thanks in advance.

You could try the quite new snap to symmetry function (2.68a and newer). You can find it in the specials (W) menu.
http://wiki.blender.org/index.php/Doc:2.6/Manual/Modeling/Meshes/Editing/Basics/Mirror#Snap_to_Symmetry

That is awesome, thank you. Oh how I wish I knew about this 2 weeks ago. Solved.