This study compared the amount of apically extruded debris during root canal preparation with three single‐file systems using liquid and gel‐based formulations of sodium hypochlorite (NaOCl) or distilled water. Seventy‐two single‐canalled roots were divided into three groups: HyFlex EDM (Coltene–Whaledent); Reciproc Blue (VDW); and F‐One Blue (Shanghai Fanta) and then divided into three subgroups: NaOCl liquid (Imicrly), NaOCl gel (Cerkamed Medical) and distilled water. The amount of extruded debris was calculated by determining the dry weight of the debris collected. Data were analysed using Kruskal–Wallis test with Bonferroni correction. Debris extrusion occurred in all subgroups. Both the instrument and the irrigant had an impact. The F‐One Blue tended to extrude the least debris, though no significant difference was observed in the pairwise comparisons between instruments. NaOCl liquid resulted in significantly more extruded debris than NaOCl gel or distilled water. The results lead us to conclude that the NaOCl gel reduced debris extrusion compared to NaOCl liquid.

The effect of solution and gel forms of sodium hypochlorite on postoperative pain: a randomized clinical trial Objectives: The aim of this study is to evaluate the effect of using gel and solution forms of NaOCI during the chemomechanical preparation of the root canals on postoperative pain at different time intervals. Methodology: 114 patients with mandibular molar teeth and symptomatic irreversible pulpitis were included in the study. All patients were divided into two groups based on the irrigant used during root canal preparation (n=57): Group 1, 5.25% NaOCI, Group 2, 5.25% NaOCI gel. All groups were filled with gutta-percha and AH Plus root canal sealer using single-cone technique. VAS scale (1-10) was used for postoperative pain assessment. After endodontic treatment, all patients were asked to record their postoperative pain levels at the 6th, 24th, 48th, 72nd hours, and 1 week later. The data were analyzed using Chi-Squared, Independent Samples T, Cochran Q and Friedman tests. Results: Statistically significant difference was not found between the distributions of pain levels at different times according to the groups (p>0.050). A statistically significant difference was observed between the distributions of pain levels measured at different times in the solution group (p<0.001). A statistically significant difference was found between the distributions of pain levels measured at different times in the gel group (p<0.001). In both groups, highest postoperative pain levels occurred in the first 6 hours. Pain levels of the gel group as 38,5% mild, 17.3% moderate, 5.8% severe and pain levels of the solution group were obtained as 46.2% mild, 26.9% moderate, 9.6% severe at the 6th hour. Conclusions: The use of the gel form of NaOCI during the chemomechanical preparation of the root canals showed similar postoperative pain when compared to the solution form.

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Background. This study aimed to examine the retreatment efficiency of four NiTi rotary file systems with micro-computed tomography (micro-CT). Methods. Forty premolar teeth were shaped up to F2 using the ProTaper Universal rotary file system and obturated with MTA Fillapex. The root canals were scanned with micro-CT to evaluate the volume of root canal filling before retreatment. The samples were randomly divided into four groups according to the file system used to remove root canal filling material (n=10): ProTaper Universal Retreatment, ProTaper NEXT, EdgeFile XR, and EdgeFile® X3 NiTi system. All the samples were scanned with a micro-CT device for the second time to evaluate the amount of residual filling material in the root canals. The percentages of filling material removed from root canals were calculated. Additionally, the time spent on the removal of the root canal filling material was recorded. The data were analyzed using the Shapiro-Wilk and Kruskal-Wallis tests. Results. There were no significant differences between the groups in the percentage of root canal filling material removal. However, a statistically significant difference was found between the groups in the time required to reach the apex and remove the entire filling material. The time required to remove the root canal filling material was higher in the EdgeFile® X3 group. Conclusion. NiTi files manufactured for root canal preparation can be used effectively and safely to remove root canal filling materials. EdgeFile XR produced for retreatment can be used as an alternative to ProTaper Universal Retreatment files.

Objectives: It is known that bioactive materials interact with the dentin to undergo biomineralization. The exact role of moisture in this interaction is unknown. Here, we investigate the effects of dentin moisture conditions on the dislocation resistance of two bioactive root canal sealers (MTA Fillapex [Angelus Solucoes Odontologicas] and GuttaFlow BioSeal [Colténe/Whaledent AG]) at 3 weeks and 3 months after obturation. Materials and Methods: Mandibular premolars (n = 120) were prepared and randomly divided into 3 groups based on the dentin condition: group 1, dry dentin; group 2, moist dentin; group 3, wet dentin. Each group was divided into 2 subgroups for root canal filling: MTA Fillapex and GuttaFlow BioSeal. Dislocation resistance was evaluated by measuring the push-out bond strength at 3 weeks and 3 months. Failure modes were examined under a stereomicroscope. Data were statistically analyzed by Kruskal-Wallis test with a significance level of 5%. Results: Moist dentin resulted in higher bond strength values for both materials at both time points. This was significantly higher than wet and dry dentin for both the sealers at the 3 months (p < 0.05), while at 3 weeks it was significant only for GuttaFlow Bioseal. The different moisture conditions demonstrated similar trends in their effects on the dislocation resistance of the 2 root canal sealers. Conclusions: The dentin moisture conditions had a significant impact on its interaction with the bioactive materials tested. Maintaining moist dentin, but not dry or wet dentin, may be advantageous before the filling root canals with bioactive sealers.