
I've tried plaque off (took me a heap of discussions with Australian quarantine to try and get it through, but finally did!!) both here and when I lived at home (UK).
I'm still not entirely sure if it helps, but my 10 year old and 7 year old both have pretty good teeth, so something is happening correctly somewhere :)
Plus they quite like the seaweed taste I'm sure.
Both are fed 'normal' kibble, have the occasional raw veg, and sometimes raw marrow bones. I also clean their teeth every couple of months and give them a bit of a scrape. I've done that since they were youngsters, so they are used to having it done. Nice big Stafford smiles all round :)
Can't hurt to give it a go welshdoglover :)