I just checked Petedge and the comb is not called a dematting comb - they are referring to it as a flea comb. My comb says "Untangler Comb". I found one on ebay and included a link for it too.
PetEdge: Flea Rid Delicate Touch Combs Untangler 5 inch Stainless Steel Pet Comb - eBay (item 200314402195 end time Mar-27-09 18:38:15 PDT)
I sprinkle a small amount of the cornstarch on the mat and work it out with my fingers as best as I can - then comb it out. The cornstarch is slippery and the mats come out very easily.