Evaluation of various filling techniques in distal canals of mandibular molars instrumented with different single-file nickel-titanium systems.

BACKGROUND AND AIMS: The aim of this study was to evaluate the quality of various filling techniques in distal canals of mandibular molars instrumented with different single-file nickel-titanium (NiTi) systems. MATERIALS AND METHODS: A total of 150 distal roots of mandibular molar teeth were randomly assigned into three main groups and instrumented by using Reciproc (VDW, Munich, Germany), WaveOne (Dentsply Tulsa, Tulsa, OK, USA), or One Shape (MicroMega, Besancon, France) NiTi file systems. The roots were then treated using one of five filling techniques: (1) Matched-single-cone, (2) cold lateral compaction with matched gutta-percha (GP) cone, (3) Thermafil filling, (4) System B/Obtura II, and (5) lateral compaction with standardized GP cones. The roots were then sectioned at three levels (coronal, middle, and apical). Photographs were acquired under a stereomicroscope, and the percentage of GP-filled areas (PGFAs), percentage of sealer-filled areas (PSFAs), and voids were measured using the ImageJ software. Comparisons between groups were applied using Student's t-test or one-way ANOVA for normally distributed data. The Mann-Whitney U-test or Kruskal-Wallis test was used when variables were not normally distributed. RESULTS: Canals filled with the System B/Obtura showed the highest PGFA and lowest PSFA, whereas those filled with matched-single-cone showed the highest PSFA and lowest PGFA (P < 0.05). The cold lateral compaction with matched GP cone group, lateral compaction group, and Thermafil filling group showed no statistically significant differences in PSFA and PGFA (P > 0.05). CONCLUSIONS: System B/Obtura technique appears to be the best technique to properly fill root canals, whereas the matched-single-cone technique in oval-shaped distal canals of mandibular molars was inadequate.

Effects of seven different irrigation techniques on debris and the smear layer: a scanning electron microscopy study.

AIM: Conventional manual irrigation with a syringe and needle remains widely accepted technique in the irrigation procedures. However, its flushing action has some limitations. Currently, several techniques and systems are available and reported to improve the insufficiency of syringe irrigation. The aim of this study was to evaluate the effectiveness of 7 different irrigation techniques compared to standard irrigation. MATERIALS AND METHODS: Straight roots from 80 extracted human maxillary central incisors were collected, and root canals were instrumented with K-files up to apical size 50. The teeth were randomly divided into 8 groups (n = 10), and final irrigation procedures were performed with 17% ethylenediaminetetraacetic acid and 5.25% NaOCl solutions using following irrigation agitation techniques: RinsEndo, EndoVac, Canal CleanMax, sonic, Canal Brush, NaviTip FX, manual dynamic irrigation, and conventional irrigation. The presence of debris and smear layer (SL) at coronal, middle, and apical thirds was evaluated by using a 5-grade scoring system with ×200 and ×1000 magnification, respectively. RESULTS: Concerning debris removal, the MM 1500 sonic group reduced apical debris significantly better than the other groups tested (P < 0.05). There was no significant difference among the tested groups (P > 0.05) related SL removal in all levels. CONCLUSIONS: MM 1500 scored best with debris removal; however, there was no significant reduction in the SL in apical third with any of the methods tested.