Hello Dr. Ellie,
I don’t know if you remember me I’m from Canada and did email you with many questions over the past year……. Everything you told me has come true….. my teeth are in good shape, I am sure they will improve even more over time….. been using mints, gum listerine and oral b rinse (we don’t have act in Canada) for over 6 months……. at first I tried using listering only once daily in the morning but in the past month using it twice morning and evening and it works better my teeth are becoming less sensitive and stronger so yes listerine twice a day is best…… like you say all along….
Thanks very much and please continue with your great work…….