Ozlek E, et al. Restor Dent Endod. 2019 Nov;45:e24. https://doi.org/10.5395/rde.2020.45.e24

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.

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. 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. 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. 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.

This study explores innovative passive ultrasonic irrigation (PUI) parameters by investigating a novel, shorter, and more repetitive agitation cycle to enhance the penetration depth of sodium hypochlorite (NaOCl) within dentinal tubules. Forty extracted human mandibular premolars were prepared (size 40, 0.06 taper) and stained with 0.5% crystal violet. Samples were divided into four irrigation groups: (I) Conventional Needle Irrigation (CNI), (II) PUI with 2 cycles of 30 s each, (III) PUI with 3 cycles of 20 s each, and (IV) PUI with 6 cycles of 10 s each. Coronal, middle, and apical sections were analyzed by light microscopy, and NaOCl penetration depth was measured at four sites (mesial, distal, buccal, lingual) using ImageJ. Data were analyzed using Kruskal-Wallis/Dunn’s test (α < 0.05). The CNI group demonstrated significantly lower NaOCl penetration compared to all PUI groups (P < 0.001). The 6 × 10 s protocol achieved significantly greater penetration in all regions (P < 0.001). While no significant differences were observed between the 2 × 30 s and 3 × 20 s protocols in the coronal and middle thirds, the 3 × 20 s group showed significantly greater penetration in the apical third (P < 0.001). The findings of this study suggest that optimizing PUI agitation parameters can lead to more effective, efficient, and predictable endodontic treatment, enhancing irrigation efficacy. Shorter and more frequent cycles (6 × 10 s) proved to be the most effective, providing valuable information for clinical practice.