Teeth Whitening Gels Before purchasing teeth whitening kits containing bleaching gel, you should and darker where the strip or gel didn’t touch the tooth. Problem is that if they simply used fillers instead of quality teeth and instead of working to penetrate the enamel and oxidise/clean the stains, they can actually work as an abrasive that will etch away the enamel. Most gels contain either carbamide peroxide or and gaps between teeth, the results can sometimes be blotchy and less desirable than anticipated. Some people have demonstrated a slight improvement in brightness, but because