I have recently heard about a Papillon who at 4 years of age was diagnosed with (internal) Dental Resorption.
It is luckily none of mine, but realize, it well could be one of them, or it could be your little friend.
When dental resorption occurs, the body actually attacks one or more teeth like it would attack a foreign body. The teeth will be simply eaten away.
The dog may experience numbness, pain, or just discomfort.
It is not a genetic disease, and it is not a very common disease, but it does happen occasionally.
The teeth affected will most likely be extracted.
Dogs can loose many teeth and still function very well, in terms of eating etc. Just hope that the canines will not have to go; they are the teeth who hold the tongue in place.