The effect of cold-light-activated bleaching treatment on enamel surfaces in vitro

Abstract

Bleaching teeth using hydrogen peroxide-based whitening agents damages the molecular structure of enamel, scientists in China report. Researchers have long debated the damage caused by tooth bleaching methods, including ‘cold-light bleaching’ — accelerating acidic hydrogen peroxide activity using blue light. Wei Li and co-workers at Sichuan University evaluated the effects of different bleaching procedures on enamel crystals in a bid to settle this debate. The researchers used X-ray diffraction — a technique used in materials science to examine crystals — to analyze the enamel non-invasively. They found that blue light alone did not affect the enamel, but whitening solutions of 35% hydrogen peroxide in the pH range of 5.2 to 5.8 caused it to demineralize. The enamel crystals decreased in size, the overall crystalline structure was less coherent, and the tooth surface also became rougher.

Keywords

dental enamel / light / micro-area X-ray diffraction / tooth bleaching

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