ABSTRACT
Introduction: One of the effecting factors in prognosis of root canal therapy is accidental procedure as broken files that may be unpreventable. Many manufacturers have designed and marketed various electromotors that can control rotational speed and torque. On the other hand, some studies have recommended applying a manual glide path to diminish contact area between the file and canal walls. The purpose of this study was evaluation of the effect of torque and a manual glide path on defects as separation of Nickel-titanium (NiTi) rotary files. Materials and Methods: This ex vivo randomized controlled trial study was carried out on 160 canals of human's matured molars with mild curvature (15-338). After initial preparation of samples and checking for inclusion criteria, in first group, preparation was carried out with air-driven handpiece, and in group two, Endo IT was used as electromotor. In both groups, Mtwo files with simultaneous technique were used for preparation. Then all data were collected and analyzed with Mann Whitny, Mantel Cox, and t-test. Results: No significant differences between two groups (P < 0.05) were observed. Based on survival analysis, safety probability of files after preparation of nine canals is 64% in group one and 69.9% in group two. There was no significant differences between this safety probability in two groups (P = 0.272). Conclusion: Usage of torque control handpiece is not an important factor, comparing instrumentation technique.
ABSTRACT
Objective:To study clinical efficacy of one-visit versus two-visit root canal therapy for pulpitis, apical periodontitis and taintless teeth with nickel-titanium rotary instruments and ultrasonic irrigation unit. Methods: A total of 309 patients with 338 teeth were selected. The teeth were classified into pulpitis group, apical periodontitis group and taintless teeth group. Patients were randomly assigned to either the one-visit or two-visit root canal therapy, the treatment effects were evaluated with clinical trial and radiography after 3 days, 1 week, 1 month and 3 months. Results: The short-term outcome was changes in apical bone density by using the periapical index (PAI), long-term outcome exhibited equally improvement in clinical curative effect in both groups. Although one-visit root treatment could cause more intensive postoperative pain than that of two-visit endodontic treatment during 1-3 days, the indisposition could be eliminated by using medicine. Conclusion: By using of the nickel-titanium rotary instruments and canal ultrasonic irrigation unit, the cure rate of root canal therapy of one-visit and two-visit endodontic treatment has been improved, with no significant difference between two groups, so that one-visit root treatment can be used in clinic.