There are two main methods for teeth whitening - in-office dental whitening done at the dentist, and at-home whitening treatments. In-office whitening involves 3-4 visits to the dentist and results in whiter teeth but costs $500-$1000. At-home whitening has advanced in recent years and there are now three main options - brush-on whitening gels, whitening strips that stick on the teeth, and trays filled with bleaching gel, with trays providing the most effective and affordable treatment.