"evaluation of endodontic treatment failure of teeth with periapical radiolucent areas and factors affecting it "

statement of problem: failure of endodontic treatment is determined on the basis of radiographic findings and clinical signs and/ or symptoms of the treated teeth. purpose: the purpose of this study was to determine endodontic treatment failure in relation to various factors influencing it in teeth with periapical lesions (clinically and radiographically). materials and methods: teeth which had periapical lesions before treatment were selected from a series of teeth treated by endodontics’ postgraduate students over 5-year period (1997-2001) in faculty of dentistry tehran university of medical science. post operative follow up in 50 patients was possible .the patient’s ages ranged between 16 to 62 years old. 40 of patients were female and 10 were male. at the recall appointment, first the clinical information (pain, swelling, tenderness to palpation, percussion, …) were recorded in a questionnaire form, then two radiographies were obtained from each tooth. the radiographies were assessed separately by three to five endodontists. strindberg's criteria were used to judge the failure of endodontic treatment. the observation period ranged from 1 to 5 years. the data were analyzed statistically by using chi-square, fisher’s exact test and mc nemar test. results: among different factors considered in this study, fistula and sensation to percussion were reduced significantly (mc nemar test, p=0.004). there were no significant difference between the extention of root canal filling, age and type of coronal restoration and endodontic failure which may be due to the small sample size of this study. conclusion: the rate of endodontic failure was 16%, which means 84% success rate, which is similar to results obtained from previous studies. the high success rate of endodontic treatment in teeth with periapical lesion may be explained by the fact that obturation has a definitive effect on reducing inflammation in periradicular area.