Evaluation of the causes of failure of root canal treatment among patients in the City of Al-Kharj, Saudi Arabia

Background: Endodontic treatment failure is one of the most common problems encountered in dentistry. Aims: This study aimed to evaluate the causes of failure of endodontic treatment among patients in the Saudi Arabian city of Al-Kharj. Subjects and Methods: A total of 250 patients of both genders were involved in the study. Criteria confirming the failure of the endodontic treatment were pain, tenderness on pressure, periapical radiolucency, and sinus tract. Patients were selected by convenience sampling methods. A diagnostic chart was prepared to complete the investigation in three different hospitals, during a six-month period (October 2018-March 2019). The results were analyzed statistically using Chi-square test and use of simple arithmetical methods to determine percentage and frequencies. Results: The main cause for endodontic failure was poor quality adjunctive treatment. 147 out of 179 male patients and 53 out of 71 female patients received poor quality treatment. There was a statistically significant difference between gender versus adjunctive treatment (P=0.009) and between hospital versus adjunctive treatment (P=0.005), and quality of adjunctive treatment between private hospital as compared to government hospital which was also statistically significant (P=0.008). In quadrant wise distribution, first molars were the most commonly involved teeth. Inadequate filling of the root canal was (36.8%), missed canals (14.4), over-extension root canal fillings (12.8%), perforations (9.6%), instrumentation related (8.8%), and endodontic access preparation related (2.4%) in the decreasing order of frequency were seen as the most common causes of failure of endodontic treatment. Conclusion: First molars were the most commonly affected tooth in the failure of endodontic treatment. Poor adjunctive treatment and inadequate filling of the root canals were the most common causes of endodontic failure, more commonly seen in male than female patients and in private clinics/hospitals than government hospitals.