Anyone?
There are a couple of issues to keep in mind with ground meats.
The process of grinding increases surface area and increases the opportunity for bacteria to grow on the meat. When you consider meat, a solid slab of meat like a steak is completely bacteria-free on the inside. The outer surface is what grows the bacteria. Hence the reason why people can eat rare steaks, with only the outside of the meat cooked and the inside still raw. But when you grind meat, you are essentially slicing through the exterior of the meat, into the interior. This pushes whatever bacteria was on the outside into the inside of the meat, giving it more opportunity to grow and multiply.
Grinding adds another step of processing, as well. So more steps that can add contamination to the meat, more contact with processing equipment.
Finally, not all ground meat is created equally. Your average grocery store ground beef may have added fillers to decrease fat percentage or add bulk. These fillers are often grain based, and are not listed on the labels. Not necessarily a BAD thing ... but if you are trying to stay away from grains or have a dog with grain sensitivies, it is something to keep in mind.
All of these things together, with the loss of dental benefits that you mentioned, decrease the value of ground meats. That is not to say that you should avoid all ground meats, but be aware of the risks and feed in moderation. Beef around here is incredibly expensive, so if I cannot get my hands on a deal or find sale cuts, I will purchase ground beef and feed it. But I make sure that it does not make up a majority of the diet, maybe 10% or so.
