THE EFFECT OF FINAL IRRIGATION MATERIALS AND TECHNIQUES ON THE CLEANLINESS OF THE SMEAR LAYER IN THE APICAL THIRD OF THE ROOT CANAL

BackgroundThis study aimed to compare the smear layer removing efficacy of the EndoActivator, EndoVac and Er:YAG laser in extracted mandibular premolars, at the apical, middle and coronal third of root canal, through scanning electron microscopy.Material and Methods40 extracted mandibular premolars were decoronated to a standardized length of 12 mm. Specimens were shaped to ProTaper F4 size and irrigated with 5.25% sodium hypochlorite at 370C between instrumentation. Teeth were divided into four groups (n=10), one control (needle irrigation) and three experimental, according to the irrigant activation technique used i.e. sonic irrigation (EndoActivator), apical negative pressure (EndoVac) or laser (Er:YAG). The final irrigants used were 10ml,17% ethylenediaminetetraacetic acid (EDTA) and 10ml, 5.25% sodium hypochlorite. Root canals were then split longitudinally and observed under a scanning electron microscope. The presence of smear layer at the apical, middle and coronal third of root canal was evaluated. Scores were analyzed by Kruskal-Wallis and Mann-Whitney U tests. Intraexaminer and interexaminer reliability were determined by Kappa test.ResultsThe EndoVac system was significantly more effective in removing debris from the apical third than all other groups. EndoActivator performed better than laser at the apical third. All three experimental groups (EndoVac, EndoActivator, and laser) were better than needle irrigation at the middle and apical third. At the coronal third, no significant difference was seen between the four groups.ConclusionsNone of the activation systems completely removes the smear layer from the dentine walls; nevertheless, EndoVac is significantly better in removing debris from the apical third of canal. Key words:EndoVac, EndoActivator, Er:YAG laser, smear layer, scanning electron microscopy.

Background:The main goal of endodontic treatment is to achieve cleaning and shaping prior to the filling process.Objective:This study aimed to evaluate, using atomic absorption spectrometry, the release of Calcium ions after the use of different chelating agents and protocols of agitation.Method:Ninety human canine teeth were randomly assigned to one of nine groups (n=10), as follows: 1) 0.2% Chitosan and manual agitation; 2) 0.2% Chitosan and sonic agitation; 3) 0.2% Chitosan and ultrasonic agitation; 4) 17% EDTA and manual agitation; 5) 17% EDTA and sonic agitation; 6) 17% EDTA and ultrasonic agitation; 7) distilled water and manual agitation; 8) distilled water and sonic agitation; 9) distilled water and ultrasonic agitation. Following instrumentation, all chelating substances remained inside the root canal for 3 min. Then the fluid was collected for the identification and quantification of Calcium ions. The amount of Calcium ions released in each group was compared using analysis of variance (ANOVA) and the Kolmogorov-Smirnov and Levene tests followed by Tukey’s post-hoc test. Significance was set at 5%.Results:The groups in which 0.2% Chitosan was used showed the highest concentration of Calcium ions (p<0.05). Concerning the agitation method, ultrasonic agitation showed the greatest values, followed by sonic and manual agitation (all comparisons, p<0.05).Conclusion:The present findings suggest that, among the combinations here tested, Chitosan associated with ultrasonic agitation yielded the greatest release of Calcium ions.

Background Irrigation is an essential component of root canal treatment to enable cleaning beyond the reach of mechanical instruments. The study aimed to assess and compare the efficacy of different final irrigation protocols, including sonic- and ultrasonic-powered irrigant-activation systems, on debris and smear layer removal in the coronal, middle, and apical thirds of straight oval root canals. Materials and Methods Straight oval root canals of 60 human mandibular incisors were prepared to size 40.04 and divided into four groups (n = 15) according to the final irrigation protocols: (a) Eddy sonic activation (b) endosonic passive ultrasonic irrigation (PUI), (c) irrisafe PUI, and (d) manual syringe and needle irrigation with no additional activation, which served as control. After the treatment procedures, the roots were split and observed using scanning electron microscopy. The presence of remaining debris and smear layer at the coronal, mid-root, and apical thirds of the canals were evaluated using a score system and statistically analyzed using multinominal models with significance level set at p < 0.05. Results None of the final irrigation protocols completely removed all debris and smear layer from all root canals. When the syringe and needle were used without activation, more debris and smear layer were found in the apical third of the canals. Activation of the final irrigant with each of the three devices significantly reduced the presence of debris in the apical third, compared to the syringe and needle final irrigation, with no difference among the three activation devices. Eddy and irrisafe activation also significantly reduced the residual smear layer in the apical third, compared to syringe and needle alone, while the reduction in the remaining smear layer by endosonic activation did not reach the significance level. Conclusions Removal of debris and smear layer from the apical part of the root canal by syringe and needle irrigation alone may be significantly improved by using sonic or ultrasonic activation of the final irrigant. Endosonic activation was less effective in removal of smear layer from the apical part of the canals compared to the other two activation systems.

Objectives:This study comparatively evaluated the efficacy of self-adjusting file (SAF), Endovac, and CanalBrush irrigant agitation protocols in removing calcium hydroxide (Ca(OH)2) from the root canals.Materials and Methods:Sixty extracted human mandibular canine teeth were instrumented with ProTaper rotary instruments to size #40 and dressed with Ca(OH)2. The roots were randomly assigned to four groups according to irrigant agitation protocol used (n = 15). In Group 1: Conventional syringe irrigation (no activation, control); Group 2: Rotary brush agitation (CanalBrush); Group 3: Apical negative pressure irrigation (EndoVac system); and Group 4: Sonic agitation (SAF) were used. Scanning electron microscopic (SEM) evaluation was done for assessment of Ca(OH)2 removal in the coronal and apical thirds. Statistical analysis was performed by Wilcoxon and Kruskal-Wallis tests.Results:There were statistically significant differences among the groups (P = 0.218). A statistically significant difference was seen between the test groups in Ca(OH)2 removal from the apical third of the canal (P < 0.05). In the coronal third, there was no difference between the groups (P > 0.05). The most efficient Ca(OH)2 removal in apical third was recorded in Group 3 (EndoVac) and Group 4 (SAF) (P < 0.05). In Group 4 (sonic agitation), there was no significantly difference between Ca(OH)2 removal in coronal and apical thirds.Conclusions:SAF and EndoVac showed significantly better performance than CanalBrush and conventional syringe irrigation in removing Ca(OH)2 from apical third of the root canals.

Synergistic Effect of Microbubble Emulsion and Sonic or Ultrasonic Agitation on Endodontic Biofilm in Vitro

An In Vitro Comparison of New Irrigation and Agitation Techniques to Ultrasonic Agitation in Removing Bacteria From a Simulated Root Canal

Chemomechanical preparation of the root canal system is considered to be the most important part of root canal treatment, including both mechanical removal of tissue remnants and dentine chips, and chemical elimination of biofilm and microorganisms. A number of different solutions and agitation techniques have been proposed for that purpose. It was the aim of the present study to investigate whether root canal cleanliness can be improved by using a hydroxyapatite nanoparticle-containing solution with and without sonic or ultrasonic agitation. Seventy-four single-rooted teeth were divided into four experimental groups (n = 15) and two control groups (n = 7). All teeth were split longitudinally and a groove and three holes were cut into the root canal wall and filled with dentinal debris. Final irrigation was performed using sodium hypochlorite or a hydroxyapatite nanoparticle-containing solution (Vector polish) activated with a sonically or an ultrasonically driven endodontic file. Two calibrated investigators rated the remaining debris using a four-score scale. The results were analyzed using a non-parametric test with < 0.05. Sonic and ultrasonic irrigation with sodium hypochlorite cleaned the grooves and holes well from debris. The hydroxyapatite nanoparticles activated by a sonic file cleaned grooves and holes equally well. Ultrasonically activated nanoparticles performance was clearly inferior. The syringe control-group left large amounts of debris in grooves and holes. The use of the hydroxyapatite nanoparticles used in this study did not improve removal of debris.

Introduction The aim of this study was to evaluate the efficacy of new rotary NiTi instrument XP endo SHAPER (XPS) used with conventional irrigation protocol on the root canal cleaning in the apical area. Material and methods The research was conducted in vitro on 40 extracted single-rooted teeth divided into the four groups. Instrumentation in the first group was performed using iRa Ce NiTi rotary instruments, in the second group the same instruments were used plus XP endo FINISHER (XPF) for smear layer removal. In the third group, canal instrumentation was done using new instrument XPS, and in the fourth XPS instruments plus XPF was used. During the instrumentation 2% NaOCl solution was used for rinsing canals. The SEM analysis of the cleaning quality in the apical third of the canal was performed on longitudinal root cross-sections and standardized microphotography with a 2000x magnification. Results The thickest smear layer in the apical third was recorded in the first group (iRa Ce) NiTi instruments (2.12), and somewhat less in the group with the new XPS instrument (1.95). An identical and somewhat smaller amount of smear layer was registered in the second and fourth groups where XPF was used with the final irrigant (1.64) (p&lt;0.001). Conclusion The application of only one instrument (XPS) in the canal enabled efficient cleaning of a very complex apical third. Cleaning was more efficient when XPF was used with final irrigant after the canal instrumentation.

Aim: The purpose of this study was to evaluate and compare the efficacy of EDTA, carbonated water, and chloroquick in smear layer removal at apical, middle, and coronal third of the root canal. Materials and Methods: Eighty freshly extracted human mandibular premolars were used for the study The teeth were decoronated to obtain standardized working length of 14 mm. All samples were instrumented with ProTaper gold till apical size #F3 with 3% NaOCl irrigation between each file. The samples were randomly divided into four groups (n = 20) on the basis of final irrigant used: Group I: 17% ethylenediaminetetracetic acid (EDTA), Group II: carbonated water, Group III: chloroquick solution, and Group IV: normal saline (negative control). The samples were then split into longitudinal sections and observed under scanning electron microscope (SEM) at apical, middle, and coronal levels for the amount of smear layer present. Statistical Analysis: Data were analyzed statistically using Kruskal–Wallis analysis of variance followed by the Mann–Whitney U-test and Chi-square test. The level of significance was set at 0.05. Results: The present study showed that all the three experimental irrigants removed the smear layer equally at the middle and coronal third. At the apical third, Group III (Chloroquick solution) showed the least smear layer score (2.20 ± 0.41) followed by Group I (17% EDTA) (2.35 ± 0.49) and then Group II (Carbonated water) (2.45 ± 0.51). The P value was found to be Conclusion: Chloroquick is more effective in smear layer removal in apical third followed by 17% EDTA and then carbonated water when used as final irrigant. No statistically significant result was found in smear layer removal among the three groups at coronal and middle third of the root canal.

The objective of this study was to compare the smear layer formed on root canal walls during canal preparation of extracted human teeth by Twisted, Mtwo, and ProTaper rotary nickel titanium instruments. Sixty single rooted human premolar teeth with root curvature <25(0) were selected and randomly divided into three Groups (n= 20 teeth per Group). Three types of rotary nickel titanium instruments were used, Twisted (SybronEndo, Orange, CA, USA), Mtwo (VDW, Munich, Germany) and ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) according to manufacturer's instructions to instrument the root canals. Irrigation for all groups was performed after each instrument change with 3ml of 3% sodium hypochlorite followed by Glyde (File Prep, Dentsply, Maillefer, Ballaigues, Switzerland) as chelator paste and lubricant. Three different areas (coronal, middle and apical thirds) of the root canal were evaluated using scanning electron microscopy (SEM). The canal wall of each sample was assessed and compared using a predefined scale for the presence or absence of smear layer. Data were analysed statistically using ANOVA and Tukey HSD test Results: All three groups showed statistically significant more smear layer in the apical thirds of the canal as compared to the coronal and middle thirds (p<0.001). Mtwo rotary file system produced significantly less smear layer (p<0.001) compared to Twisted and ProTaper rotary instruments in the apical portion. Twisted Files resulted in less smear layer formation in the apical thirds of the canal compared to ProTaper rotary instruments but were statistically insignificant. Completely clean root canals were not found after instrumentation with any of the three instruments. Under the confines of this study Mtwo instruments produced significantly cleaner dentin wall surfaces throughout the canal length in comparison to Twisted and ProTaper rotary files. Twisted Files proved to be comparable to ProTaper rotary instruments with respect to canal cleanliness in the apical thirds of the root canal.

Instrumentation and irrigation balance helps in effective removal of endodontic microbes housing inside the smear layer. This study aimed to (1) evaluate whether activation of the irrigating solutions with two different systems during the final irrigation step can lead to smear layer formation in the middle and apical third of the root canal and (2) evaluate and compare the smear layer removal ability of the aqueous extracts of Emblica officinalis and Morinda citrifolia. A total of 72 single-rooted teeth were prepared up to F4 ProTaper. The specimens were assigned into eight groups of nine teeth each, according to the final irrigant and activation techniques. Further, the teeth were evaluated under SEM for endodontic smear layer at the middle and apical third. Inferential statistics included Pearson's Chi-square. Level of significance was set at 0.05 at 95% confidence level. Ultrasonic activation system showed significant (P = 0.000) amount of smear layer compared to XP-Endo Finisher file. A significant difference (P = 0.00) in the smear layer removal was observed when 6% M. citrifolia was activated with XP-Endo Finisher file both in the middle and apical third. Within the limitations of this in vitro study, it can be concluded that smear layer formation was noted with ultrasonic and XP-Endo Finisher file when saline was used as an irrigant. 6% M. citrifolia when activated with XP-Endo Finisher file showed best results among all other experimental groups.

Background/Objectives: This study aimed to assess and compare the elimination of the smear layer and microhardness of dentin in root canals after sequential versus continuous chelation using different agitation techniques. Methods: Sixty-four palatal roots of upper first molars were instrumented to size X3 (Protaper Next files). According to the irrigant solution, samples were assigned to two groups (N = 32/group), 3% NaOCl irrigation followed by 17% EDTA (sequential chelation (SC)), or dual-rinse (3% NaOCl/9% HEDP) irrigation (continuous chelation (CC)). Each group has been divided into four subgroups (n = 8/subgroup), based on agitation techniques used: conventional needle (CN) (control group), EndoActivator (EA), ultrasonic agitation (UAI), and Er.Cr.YSGG 2780 nm (laser). SEM images assessed the smear layer, and Vicker microhardness (VHN) was performed at 50 and 100 µm depths. Data were analyzed using: Kruskal-Wallis, Wilcoxon, and the Mann-Whitney U test. Statistical significance was set at p < 0.05. Results: In the UAI and laser agitation, CC significantly reduced the smear layer presence compared to SC in the apical and coronal thirds, respectively (p < 0.05), and no significant differences were observed in the CN and EA groups between SC and CC (p > 0.05). There were significantly higher VHNs of dentine in CC groups than in SC groups in all sections and depths, except in the apical of the CN group at 50 µm and the coronal section of EA and UAI groups at 100 µm. Conclusions: CC was comparable to SC in smear layer removal. CC had a less detrimental effect on dentin compared with SC.

Comparison of Dentinal Tubular Penetration of Intracanal Heated and Preheated Sodium Hypochlorite Through Different Agitation Techniques

Objective: This study aimed to evaluate the in vitro effects of BioPure™ MTAD ® and 17% EDTA on the removal of the smear layer on instrumented teeth with the aid of 1% NaOCl. Methodology: Human single-rooted teeth ( maxillary incisors and canines) (n=25) were randomly divided into two Experimental Groups (n=10/group) and a Positive Control Group (n=5/group). After the instrumentation, the final irrigation was performed with 10 mL of 17% EDTA/1% NaOCl solution in Experimental Group 1 for 1 minute and with BioPure™ MTAD ® in Experimental Group 2. Next, the teeth were cleaved, and the degree of cleanliness of the apical dentin surface was evaluated using scanning electron microscopy (SEM). Results: This study revealed that the 17% EDTA/1% NaOCl solution was more effective in removing the smear layer in the apical third of the root canal compared to MTAD (p<0.05). However, statistical analysis of the results revealed that 17% EDTA was more effective in removing the smear layer 6 mm from the apex in EXPG 1-6, which indicates that the more distant the smear layer is from the apex, the more effective is the chelating solution in removing the smear layer. Conclusion: The two tested substances were not fully effective in the complete removal of the smear layer in the apical third of the root canal, although 17% EDTA/1% NaOCl solution showed greater efficacy when compared to BioPure™ MTAD ® , particularly at 6 mm from the apex.

To evaluate (i) the effect of irrigant flow rate, needle type, needle insertion depth and apical constriction diameter and (ii) the effect of ultrasonic, sonic and manual dynamic agitation on irrigant extrusion using a recently introduced method. Thirty-two human teeth with a straight root canal were prepared to size 35, 0.06 taper and assigned to group A or B. The apical constriction diameter was 0.15-0.25 mm. Specimens were mounted on a plastic vial filled with distilled water to simulate a periapical lesion. A point-conductivity probe was used to determine the volume of irrigant extruded into the vial. Within group A, NaOCl was delivered at 0.14 or 0.26 mL s(-1) by an open-ended or a closed-ended needle at 1 or 3 mm short of working length (WL). In group B, NaOCl was agitated at high or low power either by an ultrasonically or sonically oscillating instrument inserted at 1 or 3 mm short of WL or by manual push-pull strokes of a gutta-percha cone. Results were analysed by repeated-measures anovas, at 0.05 significance. An increase in the flow rate resulted in increased extrusion (P < 0.001). The open-ended needle extruded significantly more irrigant than the closed-ended (P < 0.001). Extrusion decreased as needles moved away from WL (P < 0.001). The effect of apical constriction diameter was not significant (P > 0.454). Manual dynamic agitation extruded significantly more irrigant than sonic and ultrasonic agitation (P < 0.001). Irrigant flow rate, needle type and insertion depth and agitation technique had a significant effect on extrusion.