A prospective study of the factors affecting outcomes of non-surgical root canal treatment: part 2: tooth survival

By Ng YL, Mann V, Gulabivala K.

Date: 01/2011
Journal: IEJ


  • To investigate the probability of and factors influencing tooth survival following primary or secondary root canal treatment.


  • N= 759 primary RCTx, 858 secondary RCTx.
  • RCT carried out by post grad residents. Information about extraction of the root filled tooth was sought from the patient, the referring dentist or derived from the patient’s records and included the timing and reasons for extraction. Followed up for 2-4 years


  • Diabetes affected 1st RCT outcome and systemic steroid therapy affected retreatment.
  • If they did not have patency= less survival.
  • Extrusion of sealer did not affect the survival..
  • Perforation and cast post-core  lowered the survival
  • Significant post-operative restorative factors: presence of cast restoration versus temporary restoration; presence of cast post and core; proximal contacts with both mesial and distal adjacent teeth; and terminal location of the tooth.
  • 4-year cumulative tooth survival following primary RCTx = 95.4%
  • Secondary RCTx  95.3%
  • The presence of pre-operative pain had a profound effect on tooth loss within the first 22 months after treatment with a lesser effect beyond 22 months
  • Extrusion of gutta-percha root filling did not have any effect on tooth survival within the first 22 months but significantly increased the hazard of tooth loss beyond 22 months

Clinical Significance:

Tooth survival rate for both primary and secondary root canal therapy is 95% (many factors present).