Smear Layer Research Articles

Assessment of Smear Layer Removal and Penetration Depth of Root Canal Irrigant Using Different Irrigation Activation Systems: A Comparative Study.

The aim of the current study was to evaluate the penetration depth and smear layer removal of root canal irrigant using various irrigation activation techniques. In this investigation, sixty single-rooted premolars extracted for orthodontic purposes were chosen. Diamond burs were used to create an access cavity, and #10 K-file was used to determine the patency. About sixty samples were divided into the following three groups (20 samples in each group), group I: Irrigation with conventional needle, group II: Activation of EndoVac system, group III: Passive ultrasonic irrigation (PUI). The efficacy of the smear layer was assessed using a scanning electron microscopy at a ×2000 magnification. One-way ANOVA was used to record and analyze the data. All statistical analyses were performed with a significance level of p < 0.05. At coronal third, the maximum smear layer was removed in group II (1.26 ± 0.02) followed by group III (1.84 ± 0.16) and group I (2.89 ± 0.21). At middle third, smear layer removal was maximum in group I (1.18 ± 0.10) followed by group III (1.72 ± 0.09) and group I (2.66 ± 0.18). At apical third, the more smear layer was removed in group II (1.02 ± 0.01) followed by group III (1.58 ± 0.08) and group I (2.38 ± 0.06). There was a highly significant difference found between the three different irrigation systems at all three levels (p < 0.001). In conclusion, every irrigation device that was evaluated was successful in removing the smear layer from the root canal. However, the EndoVac system group removed a greater amount of smear layer compared with PUI and conventional needle group. With the goal of promoting cleaning that is beyond the ability of mechanical devices, irrigation is a crucial part of root canal therapy. If an efficient irrigation delivery system is used, the irrigants can reach the working length (WL). This type of distribution system needs to provide a suitable amount of irrigants up to the WL, as well as have enough flow and be effective at debriding the entire canal system. How to cite this article: Pujari MD, Das M, Das A, et al. Assessment of Smear Layer Removal and Penetration Depth of Root Canal Irrigant Using Different Irrigation Activation Systems: A Comparative Study. J Contemp Dent Pract 2024;25(4):331-334.

Evaluation of the Smear Layer Removal Ability of Various Rotary Files with/without Chemical Agents on Primary Teeth: An In Vitro Study.

The aim of the current study was to assess the cleaning and smear layer removal efficacy of two different rotary files with or without chemical agents on primary teeth. For the study, 90 extracted primary maxillary incisors without internal or external resorption and with at least two-thirds of complete roots were chosen. Then, based on the kind of instruments used to clean and shape the canals, they were randomly assigned to three experimental groups, each consisting of 30 teeth. Group-I: The canal was instrumented manually with K-files, Group-II: The canal was instrumented with Kedo-S files, Group-III: The canal was instrumented with Kedo-SG Blue files. After the canals were finally instrumented, 2 mL of QMixTM solution was used to irrigate 15 samples from each group. The samples were subsequently allowed to remain in the canals for 90 seconds in order to eliminate the smear layer. After that a stereomicroscope was used to assess the cleaning effectiveness. With irrigant solution, the highest mean value was found in manual K-files (2.86 ± 0.34), followed by Kedo-S files group (1.34 ± 0.26) and Kedo-SG Blue files (1.28 ± 0.18). Without irrigant solution, the highest mean value was found in manual K-files (2.92 ± 0.22) followed by Kedo-S files group (1.44 ± 0.18) and Kedo-SG Blue files (1.36 ± 0.14). There was a statistically significant difference found at all the three levels. On conclusion, the current study's findings demonstrated that irrigation solution was significantly more effective in cleaning and removing smear layers from pediatric rotary files than manual K-files. The effectiveness of endodontic therapy depends on a successful chemomechanical preparation. The canals are instrumented using either hand files or rotary instruments; there are several irrigation and instrumentation techniques. In order to completely sterilize the canals, chemical agents are utilized for irrigation during instrumentation. Due to their numerous biological, antibacterial, anti-inflammatory, and antioxidant qualities, many natural compounds are also utilized as irrigants. How to cite this article: Abushanan A. Evaluation of the Smear Layer Removal Ability of Various Rotary Files with/without Chemical Agents on Primary Teeth: An In Vitro Study. J Contemp Dent Pract 2024;25(4):354-357.

Antimicrobial efficacy of DJK-5 peptide in combination with EDTA against biofilms in dentinal tubules: Primary irrigation, recovery and re-irrigation.

To investigate the dynamic recovery of biofilms within dentinal tubules after primary irrigation with different protocols, and to evaluate the efficacy of various re-irrigation protocols on recovered biofilm, considering factors such as smear layer, nutrient conditions, and primary irrigants. A total of 416 mono or multi-species biofilms samples were prepared from human teeth and incubated for 3 weeks. After inducing a smear layer on half of the samples, all specimens were irrigated with one of the following irrigant sequences: (1) 6% NaOCl +17% EDTA, (2) 6% NaOCl +8.5% EDTA, (3) 6% NaOCl and (8.5% EDTA +10 μg/mL DJK-5 antimicrobial peptide), or (4) sterile water. Thirty-two samples were used to assess immediate effect, whilst the rest were re-incubated to assess biofilms recovery. Nutrient conditions were defined based on whether culture media were changed (nutrient-rich) or not (nutrient-poor) during re-incubation. After 16 weeks, recovered biofilms underwent re-irrigation using four additional protocols, with or without DJK-5 peptide, based on primary irrigants. Confocal laser scanning microscopy was employed to evaluate immediate irrigant effects, biofilms recovery intervals (1, 3, 5, 8, 12, and 16 weeks after primary irrigation), and re-irrigation effects at the 16-week. Statistical analysis included one-way anova and two-way mixed anova tests. The DJK-5 peptide irrigation protocols demonstrated the highest killing rates during primary irrigation and resulted in a longer biofilms recovery time of 16 weeks compared to non-peptide protocols (p < .001). Both primary irrigation type and smear layer presence significantly influenced biofilms recovery (p < .001). In the absence of smear layer, re-irrigation efficacy didn't significantly differ from primary irrigation, regardless of primary irrigation type or nutrient conditions. However, with a smear layer present, re-irrigation led to significantly higher proportion of dead bacteria compared to primary irrigation (p < .05). Inclusion of the DJK-5 peptide into the re-irrigation protocol displayed superior killing rate compared to other protocols (p < .001). Biofilms exhibited susceptibility to both peptide and non-peptide protocols during re-irrigation, irrespective of nutrient conditions or primary irrigation protocols. The DJK-5 peptide irrigation protocols consistently displayed superior effectiveness compared to non-peptide protocols.

In Vitro Efficacy of Apical Negative Pressure Irrigation in Primary Teeth: A Smear Layer Analysis.

This study aimed to assess the efficacy of root canal debris removal in primary teeth through irrigation using the Endo-Irrigator Plus (CWAIS). A total of 25 primary mandibular first molars were divided into five groups, with five teeth in each group. After determining the working length and performing biomechanical preparation, groups I and II were subjected to hand and rotary instrumentation (ProTaper, Dentsply, United States of America) with conventional syringe irrigation with positive pressure, while groups III and IV were instrumented using hand and rotary instrumentation with positive and negative pressure irrigation employing the Endo-Irrigator Plus (CWAIS) system. Sodium hypochlorite (5.25%) and ethylenediaminetetraacetic acid (EDTA) (17%) were used as irrigants. Group V served as the control group, undergoing only root canal access opening. The removal of the smear layer was analyzed at the cervical, middle, and apical thirds of the canal using environmental scanning electron microscopy (SEM). Statistical significance was set at p < 0.05. Statistically significant differences were observed among all groups at the cervical, middle, and apical levels (p < 0.05). Groups III and IV exhibited significantly lower smear scores at all levels, particularly in the apical third, as observed through SEM examination. The use of the Endo-Irrigator Plus (CWAIS) system demonstrated superior debridement of intracanal debris in primary teeth compared to the positive pressure irrigation method. Badnaware SD, Kakade A, Takate V, et al. In Vitro Efficacy of Apical Negative Pressure Irrigation in Primary Teeth: A Smear Layer Analysis. Int J Clin Pediatr Dent 2024;17(6):653-657.

Qualitative and Quantitative Evaluation of the Effects of Different Chelating Agents on the Calcium Content of Root Canal Dentin Using Atomic Absorption Spectrophotometer: An In Vitro Study.

Evaluation of the effects of different chelating agents on the calcium loss of root canal dentin. Around 65 single-rooted teeth were collected and decoronated. The working length was determined, and biomechanical preparation was done in a crown-down fashion using the HyFlex Control Memory rotary nickel-titanium (Ni-Ti) system until apical preparation of 30.04. Canals were irrigated with chelating agents and sodium hypochlorite between each file insertion. Based on the type of chelating agents used, the samples were randomly divided into five groups (n = 13)-group I, liquid ethylenediaminetetraacetic acid (EDTA); group II, EDTA and chlorhexidine (CHX); group III, etidronic acid; group IV, SmearClear; and group V (control), distilled water. The total volume of the solution used was collected, and calcium ion release was quantified using an atomic absorption spectrophotometer. The qualitative analysis was done by observing the acetylene (C2H2)/air flame. Images were obtained for each sample, compared, and analyzed. With respect to the control group, groups IV and I show a statistically significant difference compared to groups II and III (p < 0.05). Qualitatively, the highest intensity was observed in group IV and the least intensity in group III. SmearClear showed significantly higher decalcifying capability compared to EDTA, EDTA and CHX, and etidronic acid. Hence, its combined use with an organic solvent can be recommended for efficient smear layer removal. Minimally invasive endodontic treatment is aimed at preserving the strength of the treated tooth without compromising cleaning effectiveness. Therefore, comparing the efficacy of different chelating agents will be promising with respect to maximum calcium loss both qualitatively and quantitatively. Singhal P, Raisingani D, Prasad AB, et al. Qualitative and Quantitative Evaluation of the Effects of Different Chelating Agents on the Calcium Content of Root Canal Dentin Using Atomic Absorption Spectrophotometer: An In Vitro Study. Int J Clin Pediatr Dent 2024;17(6):647-652.

In Vitro Investigation of the Effects of Various Reducing Agents on Dentin Treated with Hydrogen Peroxide.

We assessed the effect of non-protein thiols (NPSH), reduced glutathione (GSH) and n-acetylcysteine (NAC), on resin shear bond strength (SBS) to hydrogen peroxide (H2O2)-treated dentin, and their effects on the characteristics of dentin in comparison to ascorbic acid (AA) and sodium thiosulfate (STS). H2O2-treated dentin was conditioned with 5% AA, GSH, NAC, or STS applied for 1 or 5 min. The positive control group received H2O2 without antioxidant application, and the first negative control group received distilled water (DW). The specimens received resin bonding immediately after treatment except for the second negative control group (delayed bonding). Microhardness, roughness, and topography were studied. The SBS values of all antioxidants were statistically greater than the positive control group (p < 0.05); however, NAC and AA applied for 1 min demonstrated the highest values, which were comparable to delayed bonding. All treatments removed the smear layer except DW, H2O2, and STS. The negative effect of H2O2 on resin-dentin bonding was mitigated by the application of the antioxidants; however, their efficiencies were dependent on the antioxidant type and time of application. NAC was more effective in optimizing resin bonding to bleached dentin compared to GSH at 1 min application and STS at both application times but was comparable to AA. Negligible negative effects on the substrate's roughness and microhardness were detected. The antioxidant properties of the agent and its capacity to remove the smear layer are the processes underpinning the ability of a certain antioxidant to reverse the effect of H2O2 on bonding.

Effect of Chitosan Irrigant and Lubricating Gel on Bond Strength of Resin Sealer to Radicular Dentin: An In Vitro Study.

The adhesive strength of sealers to dentin is influenced by various factors, and the presence of a smear layer is among the critical variables. Chitosan, known for its dentin compatibility, has previously demonstrated a reduction in dentin change and resin sealer bond strength comparable to ethylenediaminetetraacetic acid (EDTA) when used as an irrigant and final rinse. The study investigates the impact of chitosan, used as both a lubricating gel and final rinse, on the push-out bond strength of resin sealer. Forty single-rooted premolar teeth, each with a fully formed root and a single root canal, were collected post-extraction. During canal preparation, 1 mlsodium hypochlorite (3%) was used for irrigation at every change ofinstrument, followed by applying specific chelating gel and final rinse for each experimental group. The groups included: Group 1 (17% EDTA chelating gel, final rinse with saline), Group 2 (17% EDTA chelating gel, final rinse with 17% EDTA solution), Group 3 (chitosan chelating gel, final rinse with saline solution), and Group 4 (chitosan chelating gel, final rinse with 0.2% chitosan solution), 10 specimens in each group.After obturation, specimens were sealed and incubated for a week at 37°C with 100% humidity. The universal testing machine was used for push-out tests, and specimens were examined using a scanning electron microscope (SEM) to identify various types of bond failure. Among the four groups, Group 2 exhibited the highest mean push-out bond strength (7.33 ± 0.26 MPa), followed by Group 4 (5.33 ± 0.25 MPa), Group 1 (4.61 ± 0.30 MPa), and Group 3 (2.94 ± 0.32 MPa). The variations in bond strength suggest a notable impact of the chelating agents and final rinse solutions on the resin sealer's interaction with dentin. The study concludes that the use of EDTA as both a lubricating gel and a final rinse significantly enhances push-out bond strength, outperforming chitosan in this study. Groups with saline as the final rinse (Group 1 and Group 3) exhibited the least bond strength, highlighting the importance of the final rinse in root canal therapy.

Water-soluble vitamin-E for enhancing fluorescence diagnosis in infected human dentine treated with NaOCl

IntroductionBacterial fluorescence methods are of interest in endodontics for informing endpoints for debridement. This study explored potential fluorescence quenching reversal effects of a water-soluble vitamin E conjugate (d-α-Tocopherol polyethylene glycol 1000 succinate, TPGS) when applied to polymicrobial biofilms grown on dentine that had been exposed to sodium hypochlorite (NaOCl) to cause quenching. MethodExtracted human teeth were debrided, embedded in transparent acrylic resin and sectioned. After smear layer removal, tooth dentine sections were inoculated with a polymicrobial inoculum, and cultured for 7 days to create biofilms. Samples (n = 8 per group) were exposed to 1 % or 4 % NaOCl for 2 or 4 min, and then treated with TPGS. Bacterial fluorescence readings under laser excitation at 655 nm were assessed over 10 min using a calibrated DIAGNOdent device. All data were assessed for normality (Kolmogorov-Smirnov test) and analysed with ANOVA followed by Bonferroni post-hoc tests. ResultsNaOCl at both concentrations quenched fluorescence readings of biofilms grown on dentine samples, with a maximal reduction of 40.4 % at 5 min after 4 % NaOCl. Treatment with TPGS gave faster recovery of fluorescence readings compared to the control at 5 and 10 min. ConclusionThe water-soluble antioxidant TPGS partially reversed fluorescence quenching caused by NaOCl. This agent may have value clinically for reducing the time needed for fluorescence readings to recover when NaOCl is used as an irrigant. This will facilitate more accurate assessment of endpoints for canal debridement.

Comparative Evaluation of Ultrasonic and Sonic Irrigant Activation Systems: Assessing Extrusion Risk, Debridement, and Biofilm Removal in Distinct Apical Preparation Sizes

This study aims to compare the effectiveness of ultrasonically and sonically activated irrigation in terms of extrusion risk, root canal debridement, and biofilm removal, considering distinct apical preparation sizes, through an ex vivo study in human teeth. Instrumented teeth, to an apical size of 35/.06 or 50/.06, were assigned to three different irrigation procedures: ultrasonically activated irrigation, sonically activated irrigation, and conventional manual irrigation. Apical extrusion risk was evaluated by quantifying irrigant and debris extrusion (n = 10/group). Debris evaluation and smear layer removal from the root canal wall were conducted by scanning electron microscopy (SEM) (n = 5/group), and the elimination of a mature biofilm of Enterococcus faecalis was assessed through resazurin assay and SEM (n = 10/group). For statistical analyses, Student’s paired t-test and the ANOVA with post-hoc Tukey were used. Activated irrigations exhibited a higher risk of extrusion for the larger apical size, while the risk for manual irrigation remained independent of the apical size. Substantially fewer residual debris and smear layers were observed after the activation of the irrigant, and there was a notable enhancement in biofilm elimination compared to manual irrigation (p &lt; 0.05). Notably, the effectiveness of both activated irrigations was more pronounced in root canals prepared to a size 50/.06, with ultrasonic activation showing enhanced improvements. The findings of this study underscore the substantial impact of both ultrasonically and sonically activated irrigation on the effectiveness of root canal disinfection and debridement. This impact is especially prominent with larger apical size, albeit accompanied by an increased risk of extrusion.

Comparison of push-out bond strength and apical microleakage of different calcium silicate-based cements after using EDTA, chitosan and phytic acid irrigations.

This research was aimed to evaluate push-out bond strength and apical-microleakage after application of three different calcium silicate-based cements with irrigation solutions on simulated immature teeth. 40 maxillary permanent canine teeth were used for push-out bond strength test, and 120 maxillary permanent incisors were used for microleakage evaluation. 120 root slices were divided into four main groups (EDTA, Chitosan, Phytic acid, and Saline) and immersed these solutiouns according to irrigation procedures. Each irrigation group was divided into 3 subgroups (Biodentine, MTA Repair HP, and NeoPUTTY). The prepared teeth were divided into four groups according to irrigation procedure for microleakage test. EDTA irrigation with Biodentine group showed highest push-out bond strength value and saline group with Neoputty showed the lowest push-out bond strength value. The highest microleakage value was seen in saline group with MTA Repair HP, while the lowest microleakage value was observed chitosan with Biodentine group. Chitosan and phytic acid solutions can be recommended as an alternative irrigation solution to 17% EDTA in single-session apexification treatment, since they are non-toxic, naturally occurring materials, effectively remove the smear layer, and have a positive effect on bond strength and apical leakage. RESEARCH HIGHLIGHTS: One of the factors affecting the long-term success of root canal treatment is a hermetic seal. Non-hermetic or inadequate filling triggers a chronic inflammatory reaction in periapical tissues, causing fluids to enter the spaces and negatively affecting the success of the treatment. Therefore, this study will help clinicians choose the right biomaterial and irrigation solution that will affect the success of root canal treatment.

Effect of Using 5% Apple Vinegar Irrigation Solution Adjunct to Diode Laser on Smear Layer Removal and Calcium/Phosphorus Ion Ratio during Root Canal Treatment

Effect of Using 5% Apple Vinegar Irrigation Solution Adjunct to Diode Laser on Smear Layer Removal and Calcium/Phosphorus Ion Ratio during Root Canal Treatment

Canal disinfection using Nd: YAG Laser, synchronized microbubble-photodynamic activation, and carbon quantum dots on microhardness, smear layer removal, and extrusion bond strength of zirconia post to canal dentin. An invitro scanning electron microscopic analysis.

Evaluation of the impact of the latest root canal disinfectant, that is carbon quantum dots (CQDs), synchronized microbubble-photodynamic activation (SYMPA), and Nd: YAG laser along with ethylenediaminetetraacetic acid (EDTA) as a final irrigant on the Marten hardness (MH), smear layer (SL) removal, and extrusion bond strength (EBS) of zirconia post to the canal dentin. Eighty intact single-rooted premolars were obtained and disinfected using 0.5% chloramine-T solution. Root canal preparation was performed using ProTaper files followed by obturation. The post space was prepared for prefabricated zirconia post and all the teeth were randomly divided into four groups based on the disinfection used (n = 20 each) Group 1: 5.25% NaOCl + 17% EDTA (Control), Group 2: Nd: YAG laser + 17% EDTA, Group 3: SYMPA + 17% EDTA, and Group 4: CQDs + 17% EDTA. MH, SL removal, and EBS of zirconia post-bonded to root dentin were performed using a microhardness tester, scanning electron microscope (SEM), and universal testing machine, respectively. Both intragroup and intergroup comparisons were performed using one-way analysis of variance (ANOVA) and posthoc-Tukey test for significant difference (p < .05). Group 2 samples (Nd: YAG laser + 17% EDTA) (0.24 ± 0.06 GPa) exhibited highest values of MH. Samples in group 3 (SYMPA + 17% EDTA) treated teeth unveiled the lowest MH scores (0.13 ± 0.02 GPa). Moreover, the coronal third of Group 3 specimens (SYMPA and 17% EDTA) (1.54 ± 0.31) eliminated SL from the canal with the greatest efficacy as well as presented the highest EBS (10.13 ± 0.69 MPa). However, the apical third of Group 1 samples (5.25% NaOCl + 17% EDTA) (2.95 ± 0.33) exhibited the least efficient elimination of SL from the radicular dentin as well as the lowest bond strength (5.11 ± 0.19 MPa) of zirconia post to the dentin. The SYMPA technique with 17% EDTA proved highly effective in removing the SL from canal dentin and enhancing the EBS of zirconia posts. The least preferable method for SL removal and MH improvement was found to be 5.25% NaOCl + 17% EDTA. CQDs and Nd: YAG laser demonstrated satisfactory smear layer removal properties from the canal, along with achieving appropriate bond strength of zirconia posts. RESEARCH HIGHLIGHTS: Nd: YAG laser and 17% EDTA as canal disinfectant exhibited the highest values of MH. Specimens irrigated with SYMPA and 17% EDTA eliminated SL from the canal with the greatest efficacy. The coronal third of Group 3 (SYMPA + 17% EDTA) samples unveiled the highest zirconia post-bond integrity score to the canal dentin. Cohesive failure was a dominant failure type among different experimental groups.

High-Intensity Focused Ultrasound in Dentistry: A Literature Review

Although high-intensity focused ultrasound (HIFU) has been applied widely in medicine, utilising its non-invasive dual ablation and thermal coagulation properties, its application in dentistry has primarily remained in the research phase, predominantly in in vitro studies. Nonetheless, there has been a consistent increase in the number of publications on this subject in recent decades, focusing on areas such as remineralisation of dentine surfaces, removal of smear layers, drug delivery, and microbial elimination. The number of advantages HIFU can offer, such as its non-surgical nature, absence of ionising radiation, lack of residue, and absence of aerosols, is driving this upward trend, indicating the potential for HIFU in clinical dentistry and ongoing efforts towards developing HIFU-based devices for routine dental use. This succinct review aims to outline the historical context, operational mechanisms of HIFU, summarise recent dental research, and provide a forward-looking perspective on the role of HIFU in modern clinical dentistry.

Comparative Evaluation of Solite RS3 and HyFlex Remover Retreatment Files in Conserving Remaining Dentin Thickness During Endodontic Retreatment Using Cone Beam Computed Tomography: An In Vitro Analysis.

Introduction Non-surgical retreatment is seen as a conservative choice for dealing with recurrent infections, instead of opting for periapical surgery. The retreatment processes should be promptly and efficiently carried out, utilizing a suitable armamentarium. The objective of this experiment is to evaluate the quantity of root dentin that remains following the removal of gutta-percha (GP) from the root canal employing two distinct retreatment files. Materials and methods Sixty single-rooted teeth were selected for the examination. The process of shaping and cleaning was performed using the step-back approach, with a master apical file size of 40. The smear layer was effectively eliminated by rinsing with a solution of 3% sodium hypochlorite and 17% ethylenediaminetetraacetic acid. Paper points were employed to desiccate the canals. The obturation process involved the utilization of the lateral compaction technique with the AH Plus sealer (Dentsply Sirona, NC, USA). The teeth were classified into two groups: Group I (n=30) underwent retreatment using HyFlex Remover (Coletene India, Pvt., Ltd.), whereas Group II (n=30) received therapy with Solite RS3 retreatment files (Solite Dental in Chennai, India). The remaining dentin thickness (RDT) was assessed by cone beam computed tomography at levels 3, 6, and 9 mm from the cemento enamel junction after the removal of GP. The acquired data underwent examination using an independent t-test to determine statistical significance. Results The findings demonstrate that the utilization of Solite RS3 files led to a higher level of dentin thickness remaining at 3 mm, 6 mm, and 9 mm on the mesial side in comparison to HyFlex Remover retreatment files. The observed difference was found to be statistically significant at a significance level of p<0.05 on the mesial side. Nevertheless, there was no notable disparity seen between the two file types at these three levels on the distal side (p>0.05). Conclusion Based on the obtained results of the study, it can be concluded that Solite RS3 files show promise in preserving the RDT. However, further studies encompassing diverse parameters are needed to establish a conclusive and definitive conclusion.

An in-vitro study on effects of laser activation on dye penetration in human root dentin.

To evaluate the penetration of a dye in root dentin after activation with different laser wavelengths. Palatal roots of 38 human molars were enlarged and disinfected. Irrigation activation was performed with an Er:YAG laser: @50 mJ, 15 Hz (Er:YAG); a 9.3 µm CO2 laser: @40% power (CO2); diode lasers 455 nm/970 nm: @0.8 W, 15 Hz (D455, D970) and 808/980 nm: @1 W (D808, D980) and compared to positive control: etching with 35% H3PO4 (POS); negative control: water (NEG) and conventional needle irrigation: NaOCl and ethylenediaminetetraacetic acid (EDTA) (CONV). Methylene blue solution was introduced in the canal and laser-activated or left untouched for 100 s before the roots were dried and cut into horizontal slices. Dye penetration was automatically calculated by color recognition of two samples per root third (n = 8 per group in each coronal, middle and apical root thirds). The presence and absence of a smear layer was checked in two additional samples of the negative and positive control under scanning electron microscopy (SEM). Full-depth infiltration was not achieved in any group. Dye penetration in CONV was significantly less than in Er:YAG, CO2, POS, D455, D970, D808 and similar to NEG and D980 when results of different root thirds were pooled. Laser activation using certain parameters enhanced dye penetration compared to conventional needle irrigation with NaOCl and EDTA (CONV).

Diode laser to enhance irrigation of the root canal system: systematic literature review

The use of lasers in endodontics has revolutionized the dental field by offering a precise and less invasive option to treat pulp and periapical problems. This is why the importance of the diode laser in endodontics is recognized in order to potentiate the irrigation of the root canal system. The aim of this study was to interpret, by means of a systematic literature review, the use of the diode laser to enhance root canal irrigation in endodontics. Through a systematic review, 18 original articles related to the aforementioned topic were analyzed, which were obtained from the electronic search of the following databases: Springer, BioMed Central, Multidisciplinary Digital Publishing Institute, PubMed, Wiley Online Library. In addition. It was obtained as results that it is possible to reach areas such as lateral or accessory canals that may be inaccessible for traditional irrigation techniques, eliminating dentin debris, smear layer and other residues; however, despite its advantages it should be considered that the application of the diode laser should not replace conventional treatment, but should be considered as a possible complementary treatment. It is concluded that the application of the diode laser in endodontic therapy improves the efficiency of root canal system disinfection

Efficiency of Canal Brush and Ultrasonic Activated Irrigation in Smear Layer Removal Using Two Different Chelating Agents (In Vitro Study)

Objective: This study aims to evaluate the efficiency of two different activation methods after using two different chelating agents inthe removal of the smear layer.&#x0D; Methods: In this study, seventy single-rooted mandibular premolar teeth were included, and divided into six study groups and onecontrol group according to the chelating agents and activation methods used. In groups 1,3, and 5, EDTA was used as the chelatingagent, where it was activated by Canal Brush in G3 and by Ultra Smart in G5. In groups 2,4, and 6, 7% Maleic acid was used insteadand activated by Canal Brush in G4 and Ultra Smart in G6. While in G1 and G2, no activation systems were used. The 7th group wasa negative control and purposed to verify the internal microstructure, so only distal water was irrigated (no activation and no chelatingagent was used). Samples were sectioned longitudinally and prepared for Scanning Electron Microscope (SEM) analysis in the coronal,middle, and apical parts. Statistical analysis was performed using Kruskal-Wallis and Mann-Whitney U tests. The level of significancewas set to 0.05 (P &lt; 0.05).&#x0D; Results: Although the G5 (Ultra Smart +EDTA) median score showed the best smear layer removal score, it was not statisticallysignificant in comparison with the other 5 study groups. In all groups (whether Maleic acid or EDTA were used), smear layer removalwas effective in the coronal and middle thirds while less effective in the apical third, with no statistically significant difference betweenthe chelating agents.&#x0D; Conclusions: Under the limitations of this in vitro study, no activation system was able to remove the smear layer from the root canalwall completely. However, NaOCl and EDTA's irrigation sequence combined with Ultra Smart (ultrasonic activation) obtained betterresults than the other techniques.

Evaluation of Antimicrobial Efficacy of Etidronic Acid against Enterococcus faecalis in Primary Teeth: An In Vivo Study.

In pulpectomy, to remove the inflamed or diseased pulp tissues and smear layer, the root canal is disinfected with mechanical instrumentation and copious irrigation. The purpose of this present study is to evaluate the antibacterial efficacy of etidronic acid as an irrigant in primary teeth. A total of 60 necrotic primary teeth in children aged 3-8 years were included. Of these, 30 were irrigated with 2% chlorhexidine (CHX) gluconate (group I) and 30 with 9% etidronic acid (group II). Two microbiological samples were collected with sterile paper points from the canal in both groups during the pulpectomy process-first after access opening and before the first irrigation (S1), and second after instrumentation and final irrigation, before filling (S2). The presence of Enterococcus faecalis was determined using colony-forming units per milliliter (CFU/mL) in all samples (S1 and S2). After analyzing the samples before and after irrigation in groups I and II, there was a statistically significant reduction in CFU/mL (p < 0.05). Group II had a statistically significant advantage when the two groups were compared after irrigation. As a result, etidronic acid can be recommended as a pulpectomy irrigating solution for necrotic primary teeth. Supraja AN, Arali V, Rapala H, et al. Evaluation of Antimicrobial Efficacy of Etidronic Acid against Enterococcus faecalis in Primary Teeth: An In Vivo Study. Int J Clin Pediatr Dent 2024;17(4):433-436.

Effectiveness of Chitosan Oligosaccharide as Chelating agent in Smear Layer Removal and The effect on Fracture Resistance of Endodontically Treated Teeth

One factor affecting root canal treatment's success is the cleanliness of root canal systems. Smear layer removal is needed to ensure the cleanliness of root canals. Fracture resistance is also essential things in endodontic-treated teeth. Chitosan is one of the irrigant alternatives in dentistry that is biocompatible. The study aimed to investigate the effect of chitosan oligosaccharide as a root canal chelating alternative in the cleaning smear layer and its impact on fracture resistance of endodontic treated teeth.Experimental research with 56 mandibular premolar teeth with a single canal was used. For the smear layer cleanliness test, 24 teeth were used and divided into four treatment groups. Statistical analysis used was the one‑way analysis of variance and LSD Post Hoc test. Thirty-two teeth were divided into two treatment groups for the fracture resistance test. The statistical analysis used was the Independent T-test. There was no significant difference between smear layer removal in chitosan oligosaccharide 2% and EDTA 17% groups. There was a considerable difference between fracture resistance of endodontic treated teeth in chitosan oligosaccharide 2% and EDTA 17% groups. Chitosan oligosaccharide 2% can be used as an alternative in the final irrigation of root canal treatment.

Combined use of XP-Endo Finisher and different chelating agents on the smear layer

ABSTRACT Aims: The aim of this study was to assess the effect of XP-Endo Finisher (XPF) in conjunction with three different chelating agents, namely, 0.2% chitosan nanoparticles (CNP), 17% ethylenediaminetetraacetic acid (EDTA), and 7% maleic acid (MA) on residual debris and smear layer on the root canal walls of the mandibular premolars. Materials and Methods: Eighty extracted human mandibular premolars were used in the study. Canals were prepared using an XP-Endo Shaper, and the final finishing was done with an XPF file. Teeth were randomly divided into four experimental groups based on chelating agents, Group I (XPF + 0.2% CNP), Group II (XPF + 17% EDTA), Group III (XPF + MA), and Group IV XPF + 2.5% sodium hypochlorite (NaOCl) (control group). Teeth were longitudinally split and prepared for scanning electron microscopy analysis. For comparing the smear layer and debris score between groups, the Kruskal–Wallis ANOVA was used, followed by the post hoc Bonferroni test. The level of significance was set at P &lt; 0.05. Results: Group I (XPF + 0.2% CNP) gave the best results (P = 0.001) in all the thirds of root canal, followed by Group II (XPF + 17% EDTA) with P = 0.001. Group III (XPF + MA) showed results similar to that of the control group (XPF + NaOCl) with P = 0.001. There was a significant difference in the scores between Group I (XPF + CNP) and the other three groups. Conclusion: In all three-thirds of a root canal, the use of XPF + 0.2% CNP performed best at removing the smear layer. This was followed by XPF + 17% EDTA and XPF + 7% MA. For all groups, smear layer removal was less efficient in the apical third.