If it's the toothpaste flavour, maybe try just plain baking soda? I haven't tried this on Bridie yet as we are still working on the concept of *brushing* teeth rather than just chewing the toothbrush But I know that you can use baking soda to clean teeth, it's a mild alkali so will neutralise food acids, and obviously has no flouride so you don't have to worry about them swallowing it.