This can be broadly divided, home bleach & office bleach.
In home bleaching, custom made bleaching trays are made for a particular patient and bleaching material is given along with all instructions as to how to go about the bleaching procedure.
It takes almost 4-6 weeks time for the whitest possible shade to come.Whereas the other type of bleaching is an in office procedure done in the clinic with 1 hour appointment.
Both the procedures differ in the concentration of the bleaching material being used.But the most important thing to be kept in mind is that bleaching is not a permanent procedure.
No fixed time duration can be given to anyone as it is different for all individuals.
The more strictly the instructions are followed, the more lasting is the effect.
Also the pt is put on an anti sensitivity toothpaste, 1 week prior to office bleaching & 2 weeks post bleaching as well. Just after the bleaching procedure for 1-2 days, lot of sensitivity is felt by the patient for which any normal painkiller can be taken.