The partition must not turn white

"You might not be brushing correctly. Try using the ""Bass technique""—holding the brush at a 45-degree angle and using horizontal vibrating strokes—to clean the four quadrants (top, bottom, left, and right). This will get your teeth clean in just two minutes.
If you’re not comfortable with the Bass technique, that’s okay—I’m sure you’re already very thorough in your daily brushing routine. You can continue brushing in your own preferred style, but try brushing each of the four quadrants a few extra times back and forth to ensure every area is thoroughly cleaned."