A tooth which has had a root canal treatment previously may possibly become excessively tender or painful at some time following the initial root canal treatment for various reasons. Should this occur the tooth may require additional procedures, including retreatment, apical surgery, or extraction. When retreatment is necessary, the removal of the previous root canal filling material may involve difficulties such as pulp chamber or root perforation, root fracture, or other complications. This may possibly necessitate referral to a specialist or may even require extraction of the tooth. A retreated tooth may become brittle. Because of the loss of vital tissue in the pulp chamber and root canal, a tooth may become excessively brittle and break. The tooth may be preserved with a crown build up and a crown to restore the tooth unless the fracture is too severe or too extensive.
Dr. James L. Johnson