Tatar on one back tooth

Hi, I've never had trouble before with my dogs not having white teeth - I think it is because I have rubbed oral care gel on their teeth using a finger brush, and letting them chew on rubber toys.
So you can imagine how shock I was to to find the back tooth on both sides of Frankys mouth had tartar on

I am now searching for a good dental chew which will be strong enough to last my staffies for at least 30 minutes.
I've always try to avoid giving then raw hide as my vets says they can cause a blockage in the stomach - any suggestions please.

A good raw bone

I give my guys raw bones and have (touch wood) never had any of their teeth cleaned or anything. In fact, Nola's teeth were pronounced recently by a vet as being like a 2 year old's (she's 10).

Avoid weight bearing bones from heavy animals, especially beef. They're super hard and can crack teeth. I tend to give lamb and veal bones that are softer but still give plenty of chew time. Trotters are a bit of a favourite, too.

Bear in mind that you might need to reduce main rations if you give a lot.