one of the methods of teeth whitening involves a process in which the patient performs the procedure independently. it is done using a special whitening gel applied to custom-made dental trays. these trays are prepared in a prosthetic laboratory based on an impression or scan of the patient’s oral cavity. another aspect that distinguishes this method of treatment from in-office whitening using a special dedicated lamp is the time it takes to achieve the effect of a white smile. since there is no factor accelerating the teeth whitening process, the effect is achieved gradually and predictably. patients can decide whether they want to continue whitening or if a particular stage is already satisfactory. the process of tray whitening is very straightforward. in the dental office, the patient receives necessary information and instructions to enjoy a snow-white smile.