Micro-computed tomography analysis of shaping ability of nickel-titanium instruments activated by continuous rotation or adaptive motion.

This study assessed the ability of Twisted File Adaptive (TFA), TruNatomy (TRN) and VDW.Rotate (VR) instruments activated by continuous rotation (CR) and adaptive motion (AM) to shape curved root canals. Thirty mandibular molars with two separate mesial canals 20°-40° curved were collected and scanned using micro-computed tomography (µCT). The canals were then randomly assigned into six groups (n = 10): TRN, VR or TFA instruments activated by CR or AM. TRN groups 17.02, 20.04 and 26.04; VR groups 15.04, 20.05 and 25.06; TFA groups were shaped consecutively using 15K-file, 20.04 and 25.06. After they were shaped, the canals were scanned again. The volume of removed dentin, canal transportation and centring ratio were calculated µCT images. All data were analysed using the Kruskal-Wallis test or one-way analysis of variance (p < 0.05). With both kinematics, the TRN instrument removed the least amount of dentin, the VR-CR and the TFA-AM removed the most (p < 0.05). The transportation and centring ratios among all groups were similar (p > 0.05). The volume of dentin removed, the diameter or design features of the instruments and different kinematics did not affect the centring ratio and the amount of transportation and remained within safe limits. All three instruments activated by either kinematics were found to have similar effectiveness in shaping curved root canals.

Effectiveness of endodontic complexity assessment tool (E-CAT) on the undergraduate students in an endodontic training program and its predictive capability on complications.

INTRODUCTION: Dental students face a number of challenges when it comes to performing root canal treatments (RCTs). The Endodontic Complexity Assessment Tool (E-CAT) was developed to assist dental practitioners in assessing the complexity of RCTs before beginning treatment. MATERIALS AND METHODS: The E-CAT was filled out independently by both the educator and the student. To allow educators to record scores and complexity classes, they transferred their and students' forms to the website https://www.e-cat.uk/. Students began endodontic treatment after learning about the complexity level of the case. The educators were responsible for recording any complications encountered in every case from the outset to 1 month after treatment. RESULTS: A total of 70 students, 33 in fourth and 37 in fifth-grade, were included in the study. In the cases with higher E-CAT scores, complications such as misdiagnosed, faulty access cavity, furca or coronal third perforation, insufficient root canal instrumentation, working length loss, canal blockage, overpreparation, incomplete root canal filling and overfilling were experienced significantly more often compared to the cases with lower E-CAT scores (p < .05). The number of complications (r = .40, p < .001), treatment sessions (r = .44, p < .001), and teacher support (r = .24, p < .001) positively correlated with E-CAT score (p < .05). CONCLUSION: The E-CAT is an effective tool for assisting dental students in understanding technical challenges, such as complex root canal anatomy and possible complications during treatment. Educators can also use e-CAT to pre-select clinical cases and standardise student training by offering cases of equal complexity.

Effects of injectable platelet-rich fibrin in experimental periodontitis in rats.

Injectable platelet-rich fibrin (i-PRF) is an effective biological material that positively contributes to angiogenesis, wound healing, inflammation, regeneration processes, etc. This research aimed to evaluate the effect of i-PRF in rats with experimental periodontitis. Following the development of ligature-induced periodontitis, 24 Wistar albino rats were divided into three groups. Group-1: scaling and root planing (only-SRP); Group-2: SRP + i-PRF; Group-3: only- i-PRF. Heart blood from six donors was used for the i-PRF application. i-PRF was administered as a subgingival injection in the relevant groups on the 1st, 3rd, and 7th days. The tissues were evaluated histopathologically and immunohistochemically. Also, bone structures were examined using micro-CT. According to the data obtained, no statistically significant difference was observed among the groups in terms of bone resorption, inflammation, bone volume, bone levels (mesial/distal), and IL-1ß, IFN-ɤ, TNF-α, VEGF values (p > 0.05). However, bone mineral density was statistically significantly different among the groups (Group3 > Group2 > Group1) (p < 0.0001). Subgingival injection of only-i-PRF showed promising results in periodontitis treatment but contribution to SRP has not been proved according to this study results. The study results suggested that the i-PRF application was as effective as SRP in reducing bone loss, modulating inflammatory process, and effecting cytokines in experimental periodontitis. The significant effect of i-PRF on bone mineral density was the most remarkable result.

Physical properties of MTA, BioAggregate and Biodentine in simulated conditions: A micro-CT analysis.

The aim of this study was to evaluate the physical properties of calcium-silicate based cements as retrograde filling in different pH and blood conditions using micro-CT. Eighty-four teeth were obturated and after root-end resection, 3 mm-deep root-end cavity was ultrasonically prepared. The samples were divided into four test groups (n=21). Cements were freshly prepared and analyzed with micro-CT before and after exposed. The test groups were exposed for four days to environments containing acid, alkali, or blood. An acidic pH significantly reduced the volume of all materials after four days and differed from the other environments. Biodentine has the highest percentage of loss in volume and density after treatment in an acidic environment. Porosity formation in the acidic medium was observed in Biodentine amongst all materials. The three-dimensional structures of all materials changed after exposed to an acidic pH, while fewer changes were observed in the structures of materials treated with blood and alkali.

3D Micro-CT Analysis of Void and Gap Formation in Curved Root Canals.

OBJECTIVE: This study used microcomputed tomography (micro-CT) to compare the volumes of voids and gaps in curved root canals instrumented and filled using various techniques. METHODS: Twenty extracted mandibular first molars with two curved mesial root canals were used. Root canals were instrumented using a self-adjusting file (SAF) or Revo-S file system. For standardization, mesiobuccal canals were instrumented with SAF and mesiolingual canals were instrumented with Revo-S in each root. The canals were divided into four experimental groups (n=10 in each). The canals were then filled via cold lateral compaction (CLC) or a thermoplasticized injectable technique (TT) using gutta-percha and AH Plus root canal sealer. The roots were scanned with a micro-CT, and the volumes of the voids and gaps were calculated using three-dimensional (3D) micro-CT images. Data were analyzed using unpaired t- and Kruskal-Wallis tests. A value of P<0.05 was considered significant. RESULTS: None of the tested techniques provided void- or gap-free fillings. Nevertheless, the SAF showed more gap formation than the Revo-S, and TT showed higher gap formation in all experimental groups. These differences, however, were not statistically significant (P>0.05). CONCLUSION: The SAF and Revo-S rotary file systems yielded comparable results. No statistically significant difference was found between the results of the various instrumentation and filling techniques.

Biocompatibility of a new epoxy resin-based root canal sealer in subcutaneous tissue of rat.

OBJECTIVE: The objective was to evaluate the subcutaneous biocompatibility of two root canal sealers. MATERIALS AND METHODS: Thirty female rats were distributed into two groups of 15 animals. Each received subcutaneous dorsal implants: Silicone tubes filled with AH Plus or Obtuseal. After the 11(th), 14(th), and 45(th) days, tissues were collected for biopsy and fixed and processed for histologic evaluation. Observations of the cellular inflammatory components, such as lymphocytes and macrophages, were made. The data were analyzed using Kruskal-Wallis and Connover tests (P < 0.05). RESULTS: By the 7(th) day, lymphocyte infiltration increased in both groups (P = 0.0104). However, macrophage infiltration increased only in the AH Plus group (P = 0.0011). By the 14(th) and 45(th) days, lymphocyte and macrophage infiltrations were reduced. At the end of the experimental period, no statistically significant differences were found between the AH Plus group and the Obtuseal group (P > 0.05). CONCLUSION: After 45 days, Obtuseal yielded a satisfactory tissue reaction; it was biocompatible when tested in subcutaneous rat tissue. On the basis of the obtained results, it was concluded that Obtuseal root canal sealer caused a satisfactory tissue reaction as AH plus, because it was biocompatible when tested in the subcutaneous tissue of rats.