|  
                         Internal, or non-vital, 
    bleaching is used to lighten a darkly discolored tooth that has had root canal 
    therapy. A chemical oxidizing agent is placed within the coronal portion of 
    a tooth to remove tooth discoloration. It may be performed in the dental office 
    using a procedure known as "chair side bleach." In this procedure, 
    bleach crystals are placed inside the tooth, left for a period of time, and 
    then removed before leaving the office. This may be done once or several times, 
    depending upon the discoloration of the tooth. Another method is known as 
    "walking bleach". In this procedure, bleach crystals are placed 
    inside the tooth, left for several days and then the patient returns to the 
    dental office to have the bleach crystals removed. Again, this procedure may 
    be performed one or more times, depending upon the discoloration of the tooth. 
    An endodontist commonly performs these procedures. 
                         
                        
                          
                            
                              
                                 | 
                                 | 
                               
                              
                                before 
                                  non-vital bleaching  | 
                                after 
                                  non-vital bleaching  | 
                               
                              | 
                           
                         
                         
                       |