I will only be talking about the products I have found that have been successful for treating brightened teeth. The products I am reviewing on this page are from my personal collection. If you have more products that are successful for brighter teeth then you can send them my way and I will add them to this page. If you know of any other brightening tooth product or treatment that is currently effective please leave me a comment and I will be sure to check it out. Please note that the information on this page is based on scientific studies. The study on the first tooth brightening toothpaste that I found in the early 2000's was published in 2002. The study shows that using a toothpaste containing hydroxycitric acid has a significant improvement in the whiteness of the teeth and the brightening of teeth. What it does? Hydroxycitric acid was discovered in the 1800's as a natural whitening agent. Hydroxycitric acid is a natural chemical that is used to whiten teeth. Hydroxycitric acid was first discovered when Dr. William M. Tilden first found that the whitening effects of sodium citrate could be achieved with a chemical mixture of sodium carbonate, citric acid and water.