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     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. 
    
      
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        before non-vital bleaching  | 
        after non-vital bleaching  | 
       
     
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