Our office has the Crest Whitestrips SUPREME to use for bleaching your teeth. They have the strongest % of bleach in the whitestrip line - 42% carbamide peroxide - and there are 84 strips in each kit, many more than found in the stores. The Crest Whitestrips SUPREME are safe and easy to use every six months for immediate results. Or, for more effective whitening results, let us take impressions of your mouth and make trays for you to wear. Wearing the trays for awhile each night is the very best whitening treatment available.