I had my semi-annual teeth cleaning yesterday and the hygienist spent the entire time oohing and aahing over my pearly whites. Of course I've had a dozen root canals done and an equal number of crowns put in over the years, so it's more like pearly off-whites.
Anyway, it's doubly important that you keep things clean if you have a lot of fake teeth, and I highly recommend the Waterpik Ultra Water Flosser ($60) for this purpose. Used together with the floss picks that I recommended earlier, you should be able to deny your dentist the many Mercedes payments that you'd otherwise be making for him.