Ok I looked all over the net based on what I could remember from the articles I read, but I cannot seem to find what I remembered reading. I'm guessing what I was reading may have been summary articles of a few studies.

Best I can come up with is this (after reading articles for hours);

canned food is not better than dry per se' (my mistaken memory sorry)

canned food does tend to be better than dry for uti problems because of the water content

regular dry food tends to break apart too easily for it to do much of anything for tartar control on anything but the tips of the teeth

dental/tartar control food is made with a harder kibble to promote more actual chewing and also had ingredients in them that help break up plaque so it doesn't form tartar

canned food costs more and the animal has to eat more of it because it's 75% water

dry food contains more carbs.

If I ever do see what I was looking for in the vet magazines again I'll be sure to write down a website or xeroxx the page for you guys.