Study: Teeth whitening does not damage enamel surface

A new in vivo study in the current Journal of the American Dental Association (June 2012, Vol. 143:6, pp. 580-586) showed that teeth whitening gels do not alter calcium and phosphorus concentrations on the surface of enamel.

Researchers from São Leopoldo Mandic Institute and Research Center in Brazil examined the changes in calcium and phosphorus concentrations in enamel after the use of home-use and in-office teeth bleaching treatments inside the mouth.

For this study, the researchers recruited 80 patients from the center who did not have caries and periodontal disease but had an indication for dental bleaching. The participants were randomly assigned to four groups of 20 each according to the bleaching agent used. A total of 65 participants completed the study.

The bleaching techniques used included 10% home-use carbamide peroxide, 20% home-use carbamide peroxide, 35% in-office hydrogen peroxide, and 38% in-office hydrogen peroxide. The authors evaluated the teeth before the teeth whitening treatment; during the bleaching treatment at seven, 14, and 21 days; and after the treatment at seven and 14 days.

The evaluation was done using enamel microbiopsies — a method of collecting samples from enamel without causing any injuries to the dental structure — after which they determined calcium and phosphorus concentrations in milligrams per milliliter by using a spectrophotometer.

Microbiopsies can be helpful when determining the effects of dental bleaching on the mineral content of enamel in a clinical situation, in which the teeth are constantly submitted to the remineralizing-demineralizing influence of human saliva, noted the study authors.

After analyzing each bleaching agent individually, the study authors found no differences among calcium and phosphorus concentrations at the three evaluation times. This most likely is caused by the protective effect of saliva, which promotes dilution, supplements calcium and phosphorus ions for enamel remineralization, and has a buffering capacity, they noted.

A 2009 Ohio State University study found that teeth lost some enamel hardness after the application of several different at-home teeth-whitening products (Journal of Dentistry, March 2009, Vol. 37:3, pp. 185-190).

The authors of that study used five name-brand home whiteners on samples of human teeth and compared the effects to tooth samples that received no treatment. The products used in the study were Crest Whitestrips Premium Plus, Crest Whitestrips Supreme, Nite White ACP, Oral B Rembrandt, and Treswhite Opalescence.

However, another in vivo study that examined the effect of 38% hydrogen peroxide in-office whitening agent found that the bleaching agent does not damage enamel. Researchers looked at 20 patients who received bleaching treatments with a 38% hydrogen peroxide bleaching agent four times at one-week intervals.

Dr. Amaral emphasized that further studies are needed to confirm the findings of the current study.

One Response to this post.

  1. Posted by Malo Dental Implants on 19.06.12 at 9:03 pm

    Teeth whitening products can often be harmful for the teeth as mentioned above. But there are products that contain proper amount of whitening agents that doesn’t damage the teeth enamel. The detailed information provided here is very enriching. Thanks for sharing the valuable information!