Quantitative analysis of SmearOFF and different irrigation activation techniques on removal of smear layer: A scanning electron microscope study

Assessment of LASER- induced precipitation of MTA-nanoparticles on root canal dentin surface

AIM OF THE STUDY

This study aims to evaluate the effectiveness of a 980-nm diode laser in inducing mineral trioxide aggregate (MTA) nanoparticle precipitation on root canal dentin surfaces for dentinal coverage.

MATERIALS AND METHODS

Sixty mature single-rooted teeth were decoronated at a fixed length of 16 mm and instrumented to size #40/0.04. Canals were filled with either distilled water or nanoMTA suspension and randomly divided based on the treatment modality into: G I and G II flooded with distilled water and laser irradiated at 2 Watt and 4 Watt respectively, GIII and GIV flooded with nanoMTA suspension and laser irradiated at 2 Watt and 4 Watt respectively, G V, flooded with nanoMTA suspension without laser irradiation, and G VI flooded with distilled water without laser irradiation. All samples were longitudinally split and scanned by environmental scanning electron microscopy (ESEM) to evaluate dentinal tubule (DT) occlusion and MTA surface precipitation. Image J analysis software was used to quantify open DTs, while a scoring system assessed dentine coverage.

RESULTS

Laser irradiation significantly enhanced nanoMTA precipitation and dentinal tubule occlusion. The highest dentinal surface coverage, indicated by the lowest pixel percentage, was in laser-irradiated nanoMTA suspension groups G IV (3.4 ± 3.1) and G III (16.7 ± 3), while the lowest coverage was in the non-irradiated saline group G VI (53.4 ± 9.6) (p < 0.05). Median dentinal coverage scores were also highest in G III and G IV (both = 4). G VI showed the least dentinal occlusion, with a statistically significant difference from other groups (p < 0.05).

CONCLUSION

The 980-nm diode laser effectively enhances MTA nanoparticle precipitation on root canal surfaces, improving dentinal tubule occlusion and sealing potential. Further research is warranted to optimize laser parameters, MTA suspension ratios and to assess clinical outcomes.

Comparisons of the smear layer removal efficacy of dual-action irrigants and different activation techniques

Background/purpose

Dual-action root canal irrigants containing disinfectant(s) and chelator(s) are expected to enhance root canal cleaning efficiency. This study aimed to evaluate the effectiveness of these irrigants and different activation techniques on smear layer removal.

Materials and methods

Seventy-six extracted human mandibular premolars were root canal-prepared up to an apical size of #40/0.06, grouped and irrigated as follows, and the smear layer on each third of the canal wall was evaluated using scanning electron microscopy. In Experiment 1, syringe irrigation (SI) was carried out using a dual-action irrigant (Triton or SmearOFF) or a combination of 17% ethylenediaminetetraacetic acid (EDTA) and 6% sodium hypochlorite (NaOCl) (n = 12, each). In Experiment 2, Triton was activated by laser-activated irrigation (LAI) with a novel Er:YAG laser equipment (Adverl SH, Morita Manufacturing, Kyoto, Japan), an LAI protocol called shockwave-enhanced emission photoacoustic streaming (SWEEPS), or ultrasonic-activated irrigation (UAI), and irrigated with SI (n = 10, each).

Results

In Experiment 1, the Triton group demonstrated significantly better smear layer scores than the EDTA and NaOCl combination group across all canal thirds (P < 0.05). In Experiment 2, using Triton as the irrigant, the LAI and SWEEPS groups exhibited significantly superior smear layer scores compared to the UAI group across all canal thirds (P < 0.05).

Conclusion

Triton was more effective than the combination of EDTA and NaOCl in removing the smear layer across all root canal thirds. The efficacy of Triton was further enhanced by activation with LAI and SWEEPS.

Unveiling SmearOFF Efficacy in Smear Layer Removal through Ultrasonic Activation Examined by Scanning Electron Microscopy

A layer of smear that coats the walls of root canals is produced by root canal instrumentation, which could be unfavorable to endodontic therapy. The endodontic irrigant SmearOFF is designed to effectively remove both the smear layer and bacteria concurrently. The objective of this study was to evaluate and compare the efficacy of SmearOFF and 17% EDTA in removing the smear layer across the coronal, middle, and apical thirds of root canals. Sixty-four single-canal mandibular premolar roots were chosen. Two irrigant protocols were separated into two sets of thirty-two teeth, respectively, Group 1 (6% NaOCL/SmearOFF) and Group 2 (6% NaOCl/17% EDTA.) Until X2, the ProtaperNext rotary system (Dentsply, Maillefer, Switzerland), with a COXO C-SMART Endomotor (Foshan COXO Medical instrument Co., Ltd., China) was utilized for the shaping of all teeth, the equipment settings were tuned to 300 revolutions per minute (rpm) and a torque of 3 Newton-centimeters (Ncm). Before applying the final irrigants, an initial irrigation with 6% sodium hypochlorite (NaOCl) was performed using a 27-G side-vented needle. An ultrasonic gadget, EndoUltra, was utilized to activate the irrigation. After that, the determination of how well the proposed solutions worked on the prepared teeth was conducted by scanning electron microscopy. The mean smear layer scores were lower in all three regions (coronal, middle, and apical) using 17% EDTA in comparison with the samples treated with SmearOFF. Despite that, there were no significant differences between G1, 6% NaOCL/SmearOFF and G2, 6% NaOCL/17% EDTA in smear layer removal according to Kruskal-Wallis tests and Mann-Whitney U-tests (p < 0.05). Considering the findings of this investigation, both 17% EDTA and SmearOFF serve as chelating agents, demonstrating the capability to effectively remove the smear layer. This process is facilitated with the assistance of passive ultrasonic irrigation at intervals of every third of the root canal.

Influence of bioceramic cones on the quality of root canal filling relative to bond strength and adaptation of the adhesive interface

AIM

To evaluate the bond strength (BS) and analysis of the adhesive interface in root canals filled with bioceramic gutta percha sealers and cones.

MATERIAL AND METHODS

Ninety-six maxillary canines were divided into eight groups according to the endodontic sealer (AH Plus, AH Plus Bioceramic, Bio-C Sealer or Bio-C Sealer Ion+ and gutta percha cones (conventional or bioceramic) tested. They were analyzed using the BS test, failure pattern, analysis of the adhesive interface by scanning electron microscopy and confocal laser scanning microscopy. The BS data were compared between groups using the analysis of variance test with the Turkey post-test. The chi-square test was used to assess the type of failure and the non-parametric Mann-Whitney and Kruse-Wallis tests (P < 0.05).

RESULTS

Analysis of variance showed higher BS values for the groups of bioceramic gutta percha cones in Bio-C Sealer Ion+ (8.38 ± 4.27), AH Plus Bioceramic (6.19 ± 3.28), Bio-C Sealer (5.70 ± 3.18), AH Plus (4.61 ± 2.11) and for conventional gutta percha cones in AH Plus sealers (4.26 ± 2.35), Bio-C Sealer Ion + (3.63 ± 2.29), Bio-C Sealer (2.94 ± 2.32) and AH Plus Bioceramic (1.19 ± 0.89) (P < 0.05). Relative to the type of failure and adaptation of the types of filling material, a higher percentage of mixed failures was observed (gaps between 1 µm-10 µm) for the group with bioceramic gutta percha cones (P < 0.001).

CONCLUSION

The bond between sealers and bioceramic gutta percha cones showed higher bond strength values and greater penetration into the dentin tubules.

CLINICAL RELEVANCE

The filling the root canal system with bioceramic sealers should be associated with bioceramic gutta percha cones.

How does nano-focus computed tomography impact the quantification of debris within the root canal system?

The aim of this study was to compare the quantification of hard-tissue debris by using micro-computed tomography (micro-CT) and nano-focus computed tomography (nano-CT) after root canal instrumentation. Ten mandibular molars containing an isthmus in the mesial root were scanned in a SkyScan 1172 micro-CT device with a voxel size of 12.8 µm and in a NanoTom nano-CT device with 5.5 µm. The mesial root canals were irrigated with 5 mL of saline solution at the orifice level, instrumented with Reciproc R25 files and a second scanning was performed by micro-CT and nano-CT devices for post-instrumentation images. DataViewer software was used for registering the pre- and post-operative micro-CT and nano-CT images. The root canal and the debris were segmented for quantitative analysis of the volume of the canal and volume of debris using CTAn software. Statistical analysis was performed using the T test for comparison between volume of the canal after instrumentation and volume of debris in both image modalities. The level of significance was set at p < 0.05. Nano-CT images showed higher values of debris when compared with micro-CT (p < 0.05) after root canal instrumentation. No difference was observed between the volume of the root canal after instrumentation in the two imaging methods used (p > 0.05). Nano-CT technology can be recommended as a more precise method for quantitative analysis of hard-tissue debris. Moreover, in Endodontic research it is a promising method, as it is capable of providing higher spatial and contrast resolution, faster scanning and higher image quality.

Cleaning efficacy of EDDY versus ultrasonically-activated irrigation in root canals: a systematic review and meta-analysis

BACKGROUND

Ultrasonically-activated irrigation (UAI) is effective in root canal irrigation but may damage canal walls. EDDY is a sonic activation system with flexible working tips that cause no harm to dentinal walls. This review explores the intracanal cleaning efficacy of EDDY compared with UAI in vitro.

METHODS

The systematic review was registered in the PROSPERO database (CRD42021235826). A literature search was conducted in six electronic databases. In vitro studies that compared the removal of smear layer, debris, soft tissue or microbes in root canals between EDDY and UAI were included. Data extraction and quality assessment were performed. Meta-analyses were conducted on smear layer removal and debris elimination with the standardized mean difference (SMD). Heterogeneity was measured using the I² test and the Chi² test. The random-effect model was used when I² > 50%, or p < 0.1, otherwise the fixed-effect model was applied. The level of significance was set at p < 0.05.

RESULTS

19 articles were included in this systematic review and 7 articles were included in meta-analyses. Meta-analyses on smear layer removal showed unimportant differences between EDDY and UAI at any canal third (coronal [SMD = 0.08, 95% confidence interval (95%CI): -0.29 to 0.45; p = 0.44, I² = 0%]; middle [SMD = 0.02, 95% CI: -0.44 to 0.47; p = 0.94, I² = 0%]; apical [SMD = 0.01, 95%CI: -0.35 to 0.38; p = 0.70, I² = 0%]). Meta-analyses on debris removal evaluated by scanning electron microscope (coronal [SMD = 0.03, 95% CI: -0.41 to 0.46; p = 0.27, I² = 23%]; middle [SMD = -0.24, 95% CI: -0.83 to 0.35; p = 0.80, I² = 0%]; apical [SMD = 0.24, 95%CI: -0.20 to 0.67; p = 0.36, I² = 2%]) and micro-CT (SMD = 0.36, 95% CI: -0.67 to 1.40; p = 0.03, I² = 70%) both found insignificant differences. No meta-analysis was undertaken on soft-tissue removal and disinfection due to the various study designs, but the qualitative analyses implied that EDDY achieved similar performance to UAI in both aspects.

CONCLUSIONS

Limited evidence indicated that EDDY was comparable to UAI in removing smear layer, debris, soft tissue and microbes ex vivo. Considering UAI may damage canal walls, EDDY might be a substitute for UAI in irrigation activation. But more randomized clinical trials are required to explore the clinical extrapolation of the results in this review.

Experimental Solution of Chitosan and Nanochitosan on Wettability in Root Dentine: In Vitro Model Prior Regenerative Endodontics

Aims

To compare the effect of CS and CSnp on the wettability in root dentine with other irrigation protocols with an experimental in vitro model prior regenerative endodontics. Methods and Material. An in vitro experimental study that included eighty hemisected human root distributed into 8 groups: G1- distilled water; G2- 1% NaOCl/17% EDTA; G3- hypochlorous acid 0.025% HOCl, G4- 1% NaOCl/0.025% HOCl/17% EDTA, G5- 0.2 g/100 mL CS, G6- 1% NaOCl/0.2 g/100 mL CS, G7- CSnp, and G8- 1% NaOCl/CSnp. The wettability analysis calculated the contact angle (θ) between a drop of a blood-like and root dentinal surface; topographic characterization with scanning electron microscopy (SEM) quantified the diameter and number of tubules per area; spectroscopy infrared analyses (IR-S) identified chemical changes in the inorganic (phosphate/carbonate) and organic phase (amide/methyl). Statistical analysis: a linear mixed model, Kruskal–Wallis, and Holm–Bonferroni correction (P < 0.05) were used.

Results

Significantly higher wettability for G2 (27.1 (P = 0.0001)) was found. A mean value of 67°±°for experimental groups (P = 0.07) was found, and we did not identify differences between them. The SEM identified greater tubular opening and erosion for G4 and greater dentinal permeability per area for NaOCl/CS. IR-S identified dentinal organic integrity with NaOCl-CS/CSnp compared to organic reduction promoted for NaOCl/EDTA.

Conclusions

This in vitro dentin determined an indirect association between the wettability and organic contents. The oxidative effect of NaOCl could be neutralized by CS-CSnp, and consequently, the wettability of the substrate decreases.