Comparison of the sealing ability of three filling techniques in canals shaped with two different rotary systems: A bacterial leakage study Tamer Tas ¸demir, DDS, PhD, a Kürs ¸at Er, DDS, PhD, a Tahsin Yildirim, DDS, PhD, b Kurtulus Buruk, DDS, PhD, c Davut C ¸ elik, DDS, a Sabri Cora, DDS, a Erhan Tahan, DDS, a Behram Tuncel, DDS, PhD, d and Ahmet Serper, DDS, PhD, d Trabzon and Ankara, Turkey KARADENIZ TECHNICAL UNIVERSITY AND HACETTEPE UNIVERSITY Objective. This study compared the sealing ability of 3 current filling techniques in root canals shaped with 2 different rotary systems. Study design. Eighty human extracted mandibular premolars were divided randomly into 2 similar groups of 40 each and instrumented with either ProTaper (Dentsply Maillefer, Tulsa, OK; group A) or Mtwo (VDW; Antaeos, Munich, Germany; group B) rotary systems. Each group was divided into 3 subgroups (n = 10) and 2 control groups (n = 5). Canals were filled either with the tapered single-cone technique (SC; subgroups A1 and B1), with lateral condensation (LC; subgroups A2 and B2), or warm vertical compaction (WVC; subgroups A3 and B3). AH Plus was used as a root canal sealer in all groups. Samples were sterilized in an ethylene oxide sterilizer for 12 hours. The apical 3-4 mm of the roots were immersed in brain-heart infusion culture medium with phenol red indicator within culture chambers. The coronal access of each specimen was inoculated every 48 hours with a suspension of Enterococcus faecalis. Bacterial leakage was monitored every 24 hours for 8 weeks. The data obtained were analyzed using a chi-squared test, and P was set at .05. Results. In group A, 70% of the specimens filled with SC (subgroup A1), 50% of the specimens filled with LC (subgroup A2), and 20% of the specimens filled with WVC (subgroup A3) leaked. There was no statistically significant difference between the subgroups (P  .05). In group B, bacterial leakage was observed in 50% of SC samples (subgroup B1), 40% of LC samples (subgroup B2), and 50% of WVC samples (subgroup B3). There was no statistically significant difference between subgroups B1, B2, and B3 (P  .05). There was also no statistically significant difference between group A and group B (P  .05). Conclusion. Filling with SC, LC, and WVC techniques in canals treated with ProTaper or Mtwo rotary instruments showed similar levels of sealing efficacy. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009;108:e129-e134) The purpose of root canal filling is to seal the root canal system with the aim of preventing recurrence of bacte- rial infection. By hindering microleakage between the root canal and the periapical tissues, this procedure should also deprive any surviving microorganisms of nutrients and prevent toxic bacterial products from en- tering the periapical tissues. 1-4 To date, many different materials and techniques have been developed for instrumentation and obtura- tion of root canals. During the last 15 years, root canal preparation with rotary nickel-titanium (NiTi) instru- ments has become popular. It has been reported that rotary NiTi instruments shape the root canals easily, rapidly, and more predictably while reducing proce- dural errors and maintaining the original curvature of the root canals. 5 Additionally, preparation of the root canal with rotary instruments may improve the ad- aptation between the gutta-percha point and the canal wall, because the flexible NiTi instruments may re- sult in less straightening and flaring of curved canals compared with the use of stainless steel instru- ments. 6,7 Furthermore, the use of rotary instruments may improve preparation of a uniformly round space compared with circumferential filling with hand in- struments, although the cleaning efficacy may de- pend on canal morphology. 8,9 Filling of root canals after cleaning and shaping is paramount in preventing reinfection of the root canal space. 10,11 Examples of commonly used techniques to reach this goal are cold lateral condensation (LC), a Department of Endodontics, Faculty of Dentistry, Karadeniz Tech- nical University. b Department of Operative Dentistry, Faculty of Dentistry, Karadeniz Technical University. c Department of Microbiology, Faculty of Medicine, Karadeniz Tech- nical University. d Department of Endodontics, Faculty of Dentistry, Hacettepe Uni- versity. Received for publication Mar 23, 2009; returned for revision Apr 30, 2009; accepted for publication May 5, 2009. 1079-2104/$ - see front matter © 2009 Mosby, Inc. All rights reserved. doi:10.1016/j.tripleo.2009.05.007 e129