A lot of current "wisdom" for dogs I choose to ignore. 30 years and 4 breeds/5 dogs, I've never brushed their teeth. Quest, my 13 yr old, not only has all his teeth intact, they look great. Been the case with all my dogs, with only one who broke a tooth at age 10.
I've had to reach into the mouths of two of my dogs to pull porcupine quills, which they willingly let me do with no fuss and no biting. Teaching "settle" from the first time they come into your home pays dividends their entire life. Should help calm them for teeth cleaning as well.