Lower Premolar Root Canal Retreatment
Ms. Yuan has had root canal in a lower premolar for several years (Fig.1 R). Root canal is not ideal, since there is a gap (white >, arrowhead) beside root canal filling (R). The filling itself does not extend to the root tip. X-ray shows root tip infection (black <). The premolar needs root canal treatment. But the patient feels that everything is normal. We keep close watch for three years. One day the tooth has gum infection (Fig.2 >) and pain. Ms. Yuan agrees to get root canal retreatment, although gum and root tip infections are two unrelated diseases.
To do root canal, we need to make an opening on the biting surface of the tooth (Fig.2 oval; Fig.3 between right and left arrowheads) to clean out dead, infected nerve and old root canal filling. Fig.3 G is a new root canal filling material, called gutta percha. When new root canal filling is done (Fig.4 R), it fills all the space (white >) and extends to the root tip (black >). A year later, root tip infection disappears (Fig.5 <). F in Fig.1,2,5 is filling to seal root canal filling (R) from oral cavity.
Xin Wei, DDS, PhD, MS 1st edition 05/26/2012, last revision 05/26/2012