Many recent technological advancements have been made in the field of endodontics; however, comparatively few studies have evaluated their impact on tooth survival. This study compared the survival rates of endodontic treatment performed by using classic techniques (eg, instrumentation with stainless steel hand files, alternating 5.25% NaOCl and 3% H2O2 irrigation, mostly multiple treatment visits, and so on) versus those performed using more contemporary techniques (eg, instrumentation with hand and rotary nickel-titanium files, frequent single-visit treatment, NaOCl, EDTA, chlorhexidine, H2O2 irrigation, warm vertical or lateral condensation obturation, use of surgical microscopes, electronic apex locators, and so on). Using a retrospective chart review, clinical data were obtained for 984 endodontically treated teeth in 857 patients. Survival was defined as radiographic evidence of the treated tooth being present in the oral cavity 12 months or more after initial treatment. A mixed-model Poisson regression analysis was used to compare failure rates. Of the 459 teeth in the classic group, there was an overall survival rate of 98% with an average follow-up time of 75.7 months. Of 525 teeth in the contemporary group, there was an overall survival rate of 96%, with an average follow-up time of 34 months. Considerably more treatments in the classic group were completed in multiple appointments (91%) than in the contemporary group (39%). More teeth in the classic group underwent posttreatment interventions (6.7% vs 0.9%, respectively). No statistically significant difference was noted between the two technique groups or between single or multiple visits in terms of survival. Copyright (c) 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.