Eli can't get a dental because of pulmonary stenosis, and I refuse to have another ECHO done just to get his teeth cleaned. I don't give bones, but use all sorts of treats and chews: Texas toothpicks, Twistex, Zuke's Z Ridge dental chews, munchy sticks, and Proden Plaque Off, which is a suppliment that is added to his food. His teeth are pretty clean. Cleaner than when I started using all these things.
Actually, I lied about the bones...I do give marrow bones on occassion. They are big, fun to gnaw on, and don't seem likely to splinter. I let the kids have them for about an hour, and take them away after that. This is only about once in a blue moon.
Hope this info helps!