Ketamine alone should not be given to dogs, but in combination w/other drugs.
UCSF Animal Care & Use Program - Dog Formualry
If your vet has done this lots of x's w/great success then I would think it's safe. But personally, if her teeth are in good condition, I would wait & do a thorough cleaning. That way they can get under her gums & possibly pull any teeth if need be.
Turbo has never gone under for dental cleaning & he's 5years old. He did have anesthesia free cleaning a year or 2 ago. He has little light yellowing on his back molars, that's it & no bad breath...I also brush their teeth every night. Planning to do his 1st dental cleaning @ the vet in Feb 2014 (so we can get 10% off for pet dental month) if the vet says it's time.