Is brushing your teeth in the public toilet a culture specific activity? [closed]

I have seen on a number of occasions in Australia of people brushing their teeth in a public toilet, whether it is in a library or office building. I am trying to work out whether this is something that is common to a particular culture or if there are some reasons that I don't know about (since it doesn't seem to be that common), even though I have generally only seen Asians do this.

The question I would like to know is whether it is an acceptable practice for western people to do this in an Eastern country (and vice versa), because I find it not particularly a good thing to do personally, and I want to know if this is an issue in a cross-cultural situation.