Methodology: In this descriptive study sixty patients referred for root canal retreatment in total of 78 teeth were asked about details of previous root canal treatment and subsequently examined for clinical findings and correlated with radiological observations before performing retreatment. Various reasons of failure of endodontic treatment like quality of coronal restoration, quality of obturation, missed canals, separated instruments and procedural errors were evaluated.

Results: Results showed that in most of the cases more than one cause can be attributed for failure of primary root canal treatment. Pain in root canal treated tooth was most common complaint of patients (45%) with half of cases (50%) having teeth sensitive to percussion and more than one third cases had draining sinus (35%). Both coronal restoration (66.6%) and quality of obturation (90.9%) was found below standard in majority of cases along with missed canals (24.3%), perforations (6.4%) and separated instruments (6.4%).

Conclusion: The outcome of root canal treatment is significantly affected by the quality of obturation and the presence and quality of coronal restoration. There is immense need of improving knowledge and skills of practioners to bring success rate of primary root canal treatment at par with institutions following standard protocols and procedures.