Dental powder - does it work?

[marmitedoughnut]

I'm seeing loads of adverts recently for dogs dental powder that you add to their food to clean the teeth and freshen breath.
Has anybody used it and does it actually work?

We use it (have been doing for over a year; we also brush her teeth with doggy toothpaste).

Her teeth are in good condition so I suppose the combined approach is working, but I wouldn't say it's freshened her breath!