I always use Kongs (The normal red ones) with Daisy. I have used the stuff n paste before. It is a good idea, but I find it best to stuff a kong with a mixture of naturediet dog food (which is a soft, meaty food but it's all natural with carrots and rice in it) with a few biscuits put in, then I freeze the kong, give it to Daisy the next day and it keeps her good for ages!
There are dental kongs that have grooves in designed to help clean your dogs teeth but I definitely prefer the traditional kong that you can pretty much stuff with anything! Because your dog has to really work hard to get the goodies out of the middle, it must give them a dental work-out in the process!
I use a mixture of peanut butter and dried apple pieces frozen or with doggie treats in our kong. We use a puppy kong still but are thinking about getting bigger ones since they are also getting bigger.