Can brushing my teeth twice a day whiten them?

I didnt listen to my parents as a kid and i started TRYING to make up for that these past few months. I use colgate total whitening toothpaste. I kinda want an answer from someone that has had experience with this, not a guess
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Of course, it stops plaque, etc from building up, and at night, its good to brush your teeth because you don't produce saliva at night which helps to wash away the plaque, etc during the day.
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