The primary aim of the present study is to compare the effect of root canal preparation with hand and rotary files on the severity of postoperative endodontic pain in teeth with Asymptomatic Irreversible Pulpitis.The design of this study is randomized and double blind. The inclusion criteria consist of healthy subjects requiring endodontic treatment on mandibular first or second molars with asymptomatic irreversible pulpits , normal periapical radiographic view and no use of analgesics for at least 12 hours before the endodontic treatment.
Patients under 18 years old , have sinus tract, periapical abscesses and the patients whose local anesthesia last for more than 4 hours, are excluded from the study.The sample size was estimated based on the results of a pilot study calculated at 96 subjects, with 48 in each group, by considering the results of the pilot study and at α= 0.05 and a study power of 80%. Subjects are randomly categorized into tow groups: A: rotary RaCe files B:manual k-files. After determination the working lengths and preparation procedure for each group, the root canals are dried with paper points and obturating is done during the same session with the lateral compaction technique using cold gutta-percha and AH Plus sealer. Postoperative pain is evaluated with visual analog scale . The picture is given to each patient and its completion technique , is explained. Data on pain is recorded by the patients at 4-, 8-, 12-, 24- and 48-hour and 1-week internals.The present study is carried out in 5 months duration in the Department of Endodontic, Tabriz Faculty of Dentistry on patients referring to the Department. Comparison of pain severity , number of painless patients and use of analgesics in each time periods between two groups is done.