Answer

Hi Lorna,

This is most a very difficult question. It is very dangerous to put a 21 year old animal under anesthesia. However if you don't remove that tooth, it'll continue to cause your dog pain. I agree with your caution to do such a thing. My dog of 14 yrs recently had bladder stones. The Emergency vets opted for surgery. But my girl didn't wake very well from it after her dentistry less than a year ago. I got a 2nd opinion and the vet told me surgery was not absolute and that I had the option of a special diet to take care of the problem.
You must conduct a blood test to see if your dog's major organ functions are working properly. This is used to determine whether or not your dog is a good candidate for the dentistry. I would speak to your vet about what other options you have. The vet I worked for would prescribe an oral antibiotic for life for those who feared to let their dog or cats undergo surgery at an old age. It worked and he understood their worries, as he was worried too.
I'm glad I didn't go for the surgery. My dog spent the least amount of time at the hospital, was stress free and is currently enjoying her golden years. Not putting her through that stress made me feel like I made the right choice.
If your vet is "pushy" about doing the surgery, get a 2nd opinion and see if they're willing to understand your concerns and offer you an alternative method.
I hope this helps give you direction with what you wish to do.
Best Wishes,
~Olivia