First untoward events and reasons for tooth extraction after nonsurgical endodontic treatment in Taiwan.

In this study, 857 teeth having undergone nonsurgical root canal treatment (NSRCT) in Taiwan in 2000 were evaluated during a 5-year follow-up period for first untoward events and reasons for tooth extractions. First untoward events occurred in 83 (9.7%) teeth during this follow-up period, and nonsurgical retreatment was performed for 20 (24.1%), 4 (4.8%) received apical surgery, and 59 (71.1%) were extracted. By the end of this 5-year follow-up period a total of 64 (7.5%) teeth had been extracted. There were 65 reasons for tooth extraction given by the 56 performing dentists who responded to the extraction reason questionnaires; 6 (10.7%) were attributed to endodontically related diseases, 15 (26.8%) to periodontal diseases, 26 (46.4%) to large decay or unrestorable tooth, and 18 (32.1%) to tooth fracture. The conclusion was that 7.5% of the NSRCT teeth were extracted by the end of the 5-year follow-up period, and only 10.7% of these teeth were extracted as a result of endodontically related diseases.