I'd agree with Girl In The Fire. However, if they a REALLY bad he may need some extractions, which beef bones and chicken backs don't do
My own dog was a rescue I got 2 years ago. Her breath was horrendous, her teeth needed cleaning (despite the rescue claiming to have had the done just a month or two before). My vet allowed me to watch the entire procedure, we did about 10 extractions, all of which needed to be done. She has since had only one more cleaning, after breaking a tooth off at the gum, necessitating another extraction. The cleaning left her teeth clean, but her breath stayed horrendous. She's a small dog, but the smell when she opened her mouth permeated the whole room.
We have moved to several natural tooth cleaning methods that have helped clear up her breath and kept her teeth healthy-
First, raw bones! You do not have to feed raw, (I feed kibble) you just provide raw bones for recreational chewing, once every two weeks is a fine schedule for most dogs. I like beef knuckles, I think they do a better job than marrow bones. Many pet stores carry them in the freezer section with the raw food (NOT the bones in the bone aisle) or you can ask your local meat department or butcher. Raw chicken quarters work well for larger dogs as well.
We also supplement with a product called Wysong DentaTreat. Its a powder I sprinkle over her food. It really helps her breath. If I skip it for a few days, the smell returns. I recommend it to my customers as well, and they report excellent results. The other supplement I give is CoQ10. It can help gum health. My breed is also prone to heart trouble, so we get a double whammy there. The dosage for a 20# dog is 30mg once a day.
I would probably do the dental cleaning, look at it as a fresh start, and then start a raw bone regimen. I've never had a dog NEED a dental cleaning after starting raw bones, even in dogs that have previously needed one yearly.
