Effects of the Hydroxyl Radical and Hydrogen Peroxide on Tooth Bleaching

Abstract

The mechanisms of bleaching of discolored coronal teeth using hydrogen peroxide (H2O2) were investigated. In a scanning-electron-microscopy study, the intertubular dentin and peritubular dentin were dissolved by high concentrations of H2O2, which is used for bleaching. The X-ray diffraction study showed that hydroxyapatite was not influenced by H2O2. In an electron-spin-resonance study, more hydroxyl radical (* OH) was detected as the H2O2 concentration was increased. When amino acids that are core components of dentin proteins, such as proline and alanine, were added to H2O2, the generation of * OH decreased, but there was no change when glycine was added. A nuclear-magnetic-resonance study showed that proline was degraded completely by H2O2, the structure of alanine changed slightly, and glycine was not affected by H2O2. It is suggested that H2O2 and * OH do not influence the inorganic tissue of dentin but attack the organic component of dentin. These facts suggest that * OH has the main role in tooth bleaching with H2O2.

Genotoxic potential of 10% and 16% Carbamide Peroxide in dental bleaching

“…22 Reactive oxygen and free radicals released by bleaching products in contact with cells have been shown to interact with DNA, causing some oxidative damage, such as strands and chromosomal breakage, and may alter DNA repairability. 23 This study evaluated two groups of patients treated with two different CP concentrations. According to our knowledge, this is the only in vivo study evaluating the genotoxic effects of dental bleaching directly on patients.…”

Impact of Intracoronal Dentin Treatment Prior to Bleaching on Bond Strength of Restorative Materials

“…This fact may be attributed to the mechanism of action of the bleaching agent on the dentin, with presence of the OH-radical (16) in the dentin (1). The OH-radical is a strong oxidizing agent that has high penetrating power, acts in intertubular and peritubular dentin by degradation of the organic portion, breaking the polypeptide chain by the destruction of amino-acids of the matrix (16). The presence of residual oxygen on the dentin surface may impair the penetration of resin into dentin tubules, creating an adhesive interface more susceptible to fracture (17).…”

Blanqueamiento Intracoronario De Dientes No Vitales: Una Revisión

“…Las altas concentraciones de peróxido de hidrógeno son cáusticas y queman los tejidos por contacto al liberar radicales libres tóxicos, aniones perhidroxilos o ambos compuestos. 14,25,26 Debido a su bajo peso molecular esta sustancia puede penetrar la dentina y liberar oxígeno que rompe los dobles enlaces de los compuestos orgá-nicos e inorgánicos de los túbulos dentinarios. 27 Peróxido de carbamida: es un compuesto más estable que el peróxido de hidrógeno en estado líquido.…”