Enamel Safety of a 6% H2O2 Whitening Serum With LED

Objectives: To evaluate the enamel safety with a treatment of a 6% hydrogen peroxide (HP) whitening serum with LED device.
Methods: Enamel erosion test was conducted to assess the impact of whitening treatment on the sound bovine enamel surface according to the ANSI/ADA Standard No.136: Products for External Tooth Bleaching Products. The 6% HP serum was applied 1 time a day for 10 days with an LED device (wavelength 410 nm). In each treatment, the enamel block was coated with the serum and then illuminated with the LED for 10 minutes. The treated block was submerged in an artificial saliva solution (37 °C) overnight, and next morning the coating was removed with ethanol and a cotton swab. In control treatments, the enamel blocks were soaked in the 1% Citric Acid (pH 3.9, positive control) or DI water (negative control) at 35°C for one hour. The depth of erosion (step height) on enamel surface was measured and surface morphology was captured using a 3D Laser Scanning Confocal Microscope.
Results: The criteria for enamel safety requires that surface erosion of treated enamel is no more than three times the level caused by the positive control (ANSI/ADA standard). From the step height measurements, the surface erosion of product-treated enamel shows a negligible surface loss (-0.39 ± 1.94 μm), which is significantly lower than the positive control (31 ± 11.01 μm) and met the criteria. The surface images showed that the acid challenge from the positive control group resulted in a significant mineral loss on the enamel, whereas the enamel surface treated with the product still remained intact.
Conclusions: The in-vitro study demonstrated that the 6% HP whitening serum with LED device meets the established criteria in ANSI/ADA Standard, and therefore is safe for tooth enamel.