So, you want to whiten your teeth. What a wonderful decision! You will benefit from having more self-confidence and the world will be a little richer for your tendency to smile more. You could choose an over-the-counter teeth whitening kit to do a passable job or you could opt for in-office teeth whitening to get even more stunning results. Why is there a difference? For several reasons, Markham in-office teeth whitening gives you faster, more noticeable and safer results.