In this low-cost whitening option, whitening trays are constructed by your Dentist and a Bleaching Gel is provided. The trays containing the gel are worn for around one hour per day (or overnight), and the teeth gradually and gently whiten to the desired shade.  This process usually takes from 14 to 20 applications, but can take longer for grey or tetracycline-stained teeth.  A review appointment is made to check the result after about 3 weeks.