This is also an effective way of whitening teeth. Here, the bleaching trays are customised for the patient. The impression is done on day 1, for both the upper and lower jaws. The trays get ready on day 2. Tubes of the bleach material are also provided. The patient wears these trays with the material in it at night, for 7 to 9 nights. The results are good, but it is a time consuming process.