This Teeth Whitening aka bleaching FAIL Could’ve Been Avoided 😱 | Dentist Explains In office Teeth bleaching works mainly through hydrogen peroxide—this bleaching agent penetrate the enamel to break apart stains and lighten the tooth color. The concentration and application time are what determine how effective and safe the treatment is. Generally, 2 rounds of bleaching per session are enough for most people. But if you’re not experiencing any sensitivity and feel that your teeth could still be