If, like me, you read Copley's review of Target's Whitening Strips
and after thinking OMG I need to buy these right now immediately had a flutter of anxiety (it can't be healthy to put bleach in your mouth), rest assured and whiten with impunity. Concentrations of hydrogen peroxide (at 6%) used in professional and over the counter teeth whitening processes don’t cause significant changes to tooth enamel, according to researchers at the University of Rochester.
On the other hand, the researchers found that drinking acidic fruit juices every day can have significant negative effects on the hardness and the roughness of tooth enamel. After 20 minutes of daily exposure for five days to eBright Tooth Whitening Accelerator (6% hydrogen peroxide) provided by Beyond Dental Health, which part funded the study, surface hardness was reduced by 5.6%. However, compared to 20 minutes exposure to orange juice which reduced surface enamel by an exraordinary 84.4%, the researchers concluded the teeth whitening was insignificant.
Fluoride does seem to protect against the effects of teeth whitening treatments, but not against the assault of acidic soft drinks unless at high concentrations.