Process of lightening of the teeth, usually using a chemical oxidizing agent and sometimes in the presence of heat. Removal of deep seated intrinsic or acquired discolorations from crowns of vital and non-vital teeth using chemicals, sometimes in combination with the application of heat and light. Bleaching has been achieved through short- and long-term applications of pastes or solutions containing various concentrations of hydrogen peroxide and carbamide peroxide. Normally applied externally to teeth; may be used internally for endodontically treated teeth. Usually the process of bleaching takes around 45mins. However, in New Vision Eye Center the Dentist is using laser machine to perform the bleaching.