All whitening procedures, whether performed at home or done professionally in an office, rely on the same chemical reaction to deeply penetrate and break down stains. The main difference is the cost (professional cleanings range from $500 to $1,000 compared to $10 to $40 for DIY whitening methods). And when completed in the office, the dentist can take measures to protect the gums and rest of the mouth while whitening. DIY whitening is immediate, easy to use and widely accessible at drugstores. Professional whitening treatments also tend to take longer,1 hour to 1.5 hours, whereas DIY treatments take, at most, 30 minutes. That said, results of professional whitening in an office last a bit longer (up to 1 year) compared to at-home whitening results (up to 6 months).