@bigtiddyoneesan I don't think that it is a normal occurrence in public schools but in places with rather high education rates, it isn't that weird at all.
I think that my former school was thinking about making it mandatory years ago.
@Ekfreet
I always was given the impression that it wasn't frowned upon per say, but it certainly wasn't something people with good manners would do. This is in the U.S., btw. I guess it's seen differently in different places.
People do say to brush after each meal vs just twice a day but I don’t think anyone brought tooth brushes to school here, maybe mouthwash or those breath strips;
I have seen like a slice of lifey jdrama where these bank workers brushed their teeth in the bathroom on their break