My pup's teeth were in the same position that your's is at 6 months, so I decided to wait a little before spaying to see what would happen. The adult teeth were almost all the way in, and the baby teeth didn't losen up AT ALL, so I decided to go ahead and spay and get them pulled. They weren't at all crowded, so I suspect that nothing would push them out. She was spayed 9 days ago, just shy of 7 months, and they pulled the upper canines out then.
I don't think you should worry about the one that is loosening up, it will fall out on its own. I think you have a good shot at the other one taking care of itself, too, if you just give it a little more time. If it doesn't loosen up, just have it removed when she is already under being spayed. Two procedures, one recovery.
__________________ Life is merrier with a Yorkshire Terrier! Jezebel  & Chuy  ... RIP: Barkley  Loosie  & Sassy  |