Here's a picture of what you should look for if you go to buy a comb:
http://www.google.com/imgres?q=dematting+comb+for+dogs&hl=en&biw=906&bih=599&gbv=2&tbm=isch&tbnid=qCexGdUL8U48eM:&imgrefurl=http://www.tradenote.net/keyword/Flea/%3Ftype%3Dproducts&docid=zLZd81HlyLIJEM&imgurl=http://www.tradenote.net/images/users/000/392/252/products_images/529031.jpg&w=1003&h=679&ei=qhafToW8FK7PiAKCksRj&zoom=1&iact=hc&vpx=328&vpy=300&dur=1960&hovh=185&hovw=273&tx=137&ty=143&sig=109404198093231675668&page=1&tbnh=125&tbnw=164&start=0&ndsp=15&ved=1t:429,r:12,s:0