That's interesting. Do you think it's just from the candida and not the probiotics? Or have you noticed it's since he started the probiotics? I know there are some people who naturally have a lot of plaque build up more than others for whatever reason.
I don't think we can say 100% that probiotics cause tooth decay as I don't think there are enough studies on it but I would be surprised if they did. They should be keeping bad bacteria in check that grow with the plaque that causes cavities.