Geez, is that ad from the ‘70’s? Looks like pre-Crest White Strips…
That was back in the era when people were allowed to be their natural selves in ads. Teeth can be one of four colors, grey, yellow, red, or brown, of various shades. I tried bleaching my yellow teeth, but they always go back to their natural color after a week or so. Shame that people get brainwashed into thinking the bleached grey, which is a bright white indeed, is the only acceptable color.