Rabbit teeth

Question
Mr McGyver, 4 yr old mix, is having some dental issues.  I brought him to the vet to have his nails trimmed and with a through check-up, the vet found his molars (or whatever you would call them in a rabbit) were growing into his cheek.  From what my vet told me this could be the result of not eating enough hay, not having the proper nutrition as a baby, or hereditary.
She removed  two loose teeth and filed down the others.  One month has passed and once again, she is telling me that McGyver's teeth need to be filed down.  This would not bother me if he did not have to be under anethesia to perform the procedure. Why would his teeth be in trouble this soon after just having it done.  
Is this situation commonplace with rabbits? He is my 4th and I have never heard of this problem before.

Answer
Dear Peggy,

Unfortunately, this problem is quite common in rabbits, and more common as they age.  It's good you have a vet who knows how to deal with it.

Also unfortunately, it may be an ongoing problem, since rabbit teeth grow continually (they are hypsodonts).  It may help to get him eating more grass hay, but it's also important that he gets sunlight and fresh grass, if possible, if you have an area that's safe and fenced and has no pesticides or fertilizer residues.

This article will help explain the situation in a bit more detail:

www.bio.miami.edu/hare/dental.html

Hope this helps.

Dana