It's controversial, but we had Rosie's and Poquita's (two chi mixes with heart murmurs) and our cat Edna's teeth cleaned by a groomer their whole lives. No anesthetic and no emotional trauma. The last few years, the groomer came to our house. We gave the dogs an antibiotic for a few days before the cleanings and right through until a few days after. Our vet gave us the antibiotic and always said their teeth looked great. The last few years, I also brushed their teeth at night with doggie toothpaste. They looked forward to it. Poquita made it to age 15, Edna to 19 and Rosie, to only age 10 due to genetic CHF. I know it's not the same as a deep cleaning with anesthetic at the vet's, but it is an option in some cases. None of our pets had gum disease. That would be a whole 'nother story.
R