After being in dentistry for 20 years.. Let me tell you a cheap secret.
All tooth whitening is made of peroxide. The gels run from 6 percent
peroxide to 32 percent peroxide. If you swish with hydrogen peroxide
everyday you will have the same results plus excellent gum tissue! As a
dental hygienist, I recommend swishing with peroxide for 1-2 minutes
morning and night to all my patients. It kills bacteria that causes
decay, gingivitis, periodontal disease