My family stocks up on toothpaste to the extent that it’s occasionally a relatively long time before we need to buy more. As a result of this practice, some of our supply gets pretty old…alright, very old (as far as toothpaste should be concerned).
Anyway, I got out the last tube in my personal stash and checked the expiration date and discovered that it expired in May. Of 2003. So I’m wondering if this stuff still works as a tooth paste or if the flavoring agents can spoil? Anyone?
The abrasiveness is never going to go away, so it should work as toothpaste forever. I can imagine that the “pasteness” of it could have problems over a very long time (like 10 years), and might separate out in some way that would be gross. But that would be obvious as soon as you put it on your toothbrush. And even if the flavoring went off, it almost certainly wouldn’t be toxic, so it wouldn’t hurt to just try it.
Well, it’s not going to go moldy or anything - I think you’d have a very hard time getting anything microbial to grow in it. I could see it having physical changes, like hardening or separating.
Toothpastes containing stannous fluoride will, IIRC, degrade to stannic fluoride over time. I don’t know if this has any health implications, but I seem to recall that it turns them brown.
It would seem that something happened to it in its long slumber in the bathroom closet. Tasted pretty bad to me, but I’m awaiting independent verification on that.
Yes, they do. The three approved forms of dental fluoride are sodium fluoride, stannous fluoride, and sodium monofluorophosphate. NaMFP is the most common in toothpastes these days, but SnF[sub]2[/sub] is still used in some toothpastes, and in many preparations used in the dentist’s office. Sodium fluoride, I think, is mostly used in mouthwashes and rinses. FWIW, NaMFP is the biggest pain in the ass to do QC on (or it was when I was doing it – we had to boil it in acid and titrate with thorium nitrate).