Comparison of Easydo Activator, Ultrasonic and Needle Irrigation Techniques on Sealer Penetration in Extracted Human Teeth

This study compared the effects of different irrigation systems on sealer penetration at the root apex. Forty-two single-rooted teeth were prepared and randomly divided into three groups (n = 14): group 1: needle irrigation (NI); group 2: passive ultrasonic irrigation (PUI); and group 3: Easydo Activator (EA). A solution of 3% sodium hypochlorite (NaOCl) was used for irrigation. Nine teeth in each group were filled with AH Plus sealer mixed with CY5 fluorescent dye and a single gutta-percha cone. The sealer penetration area, maximum penetration depth and percentage of sealer penetration at 5 mm and 1 mm from the apex were analyzed by confocal laser scanning microscopy (CLSM). The remaining 5 teeth in each group were subjected to test smear layer scores by scanning electron microscopy (SEM). The CLSM evaluation showed that increases in the area, depth and percentage of sealer penetration were detected at 1 mm and 5 mm from the root apex in the PUI group compared with the NI group, and greater increases were observed in the EA group (P < 0.05). The SEM experiment showed that the lowest scores for the smear layer and debris removal were achieved by the EA group when compared with the PUI and NI groups (P < 0.05). Our study supports EA was superior to PUI and NI regarding sealer penetration at the root apex during endodontic treatment, and it could provide a new technical idea for clinical root canal therapy.

Can Type of Instrumentation and Activation of the Final Irrigant Improve the Obturation Quality in Oval Root Canals? A Push-Out Bond Strength Study

To appraise the outcome of file systems and activation of the final irrigant on the push-out bond strength of root fillings in oval canals. Single-rooted mandibular premolars (n = 180) with oval canals were divided into three groups (n = 60) for instrumentation: ProTaper Next (PTN), WaveOne (WO), and Self-adjusting File (SAF). The specimens were further divided into subgroups (n = 20) and subjected to final irrigation with activation by EndoActivator or passive ultrasonic irrigation or without activation. Then, the specimens were again subdivided (n = 10) and obturated with gutta-percha and AH Plus (GP-AH) or C-Point with EndoSequence bioceramic sealer (C-EBC). One-millimeter-thick horizontal slices were cut from the apical third of the root, 5 mm from the apex, and subjected to push-out bond strength (BS) testing. Specimens for which SAF was used exhibited higher BS values than those for which PTN or WO was used (p < 0.05). Activation of the final irrigation did not affect the BS of the root fillings. Root fillings made of C-EBC presented a higher BS than those made of GP-AH (p < 0.05). Adhesive failure was more common with specimens instrumented using PTN and WO. Root canals instrumented with SAF, showed the highest bond strength values for both root filling materials. The C-EBC produced significantly higher bond strength values than those of the GP-AH.

Calcium Hydroxide Removal Using Four Different Irrigation Systems: A Quantitative Evaluation by Scanning Electron Microscopy

This study compares conventional endodontic needle irrigation, passive ultrasonic irrigation, apical negative pressure irrigation, and mechanical activation to remove calcium hydroxide from single straight root canals. Eighty-four mandibular premolars were prepared in a crown-down manner up to size #40. Two teeth represented a negative control, and another two served as a positive control. Calcium hydroxide paste was placed inside root canals. The remaining eighty samples were analyzed based on the activation techniques, and the cleanliness of the canals was quantified using Fiji’s software on 500× magnified SEM backscattered electron micrographs. Considering the whole canal, all instruments showed better performance than conventional endodontic needle irrigation in removing calcium hydroxide (p < 0.05). Irrisafe and XP-endo Finisher could remove a significantly higher amount of calcium hydroxide than Endovac (p < 0.05). Irrisafe and XP-endo Finisher have been able to remove more calcium hydroxide than EndoVac.

Advantages and application of ultrasonic irrigation in endodontics

In the current practice, evidence shows that the currently used irrigant solutions (including sodium hypochlorite combined with and without chlorhexidine or ethylenediaminetetraacetic acid) cannot achieve full cleaning outcomes of the root canal. Accordingly, recent approaches were directed to innovate more efficacious modalities that can overcome the limitations of manual instrumentation and irrigation solutions. In this context, ultrasonic irrigation has been described in the literature as a favorable approach with significantly enhanced outcomes. We have provided evidence regarding the use of ultrasonic irrigation in endodontics. Our findings indicate that passive ultrasonic irrigation is more effective than manual instrumentation in eradicating debris and achieving favorable disinfection. Besides, it has been evidenced that the modality significantly reduces the time to achieve favorable treatment outcomes compared with the traditional approaches. It has been furtherly shown that more favorable outcomes were associated with the combined use of passive ultrasonic irrigation with manual instrumentation. Therefore, it has been suggested that manual instrumentation should be used at the initial phase to achieve adequate preparation, and passive ultrasonic irrigation should be used later on to achieve root canal cleaning.

Does the Use of Use of Continuous or Passive Ultrasonic Irrigation Protocols Improve the Removal of Smear Layer? A Scanning Electron Microscopic Study

The aim of this study was to evaluate the effectiveness of smear layer removal after the use of different irrigation methods (passive ultrasonic irrigation [PUI], continuous ultrasonic irrigation [CUI], apical negative pressure irrigation and conventional irrigation) using the scanning electron microscopy (SEM) as an analytical tool. A total of 100 single-canal teeth were decoronated and randomly divided into five groups (n = 20) according to the irrigation method used: conventional irrigation with front outlet syringe, conventional irrigation with lateral outlet syringe, apical negative pressure irrigation (EndoVac), PUI with Irrisafe, and CUI with ProUltra PiezoFlow ultrasonic irrigation needle. Root canal preparation was performed with the ProTaper Gold system up to the F4 instrument and 5.25% NaOCl was used as an irrigant. After chemical-mechanical preparation, the roots were split longitudinally, and the coronal, middle and apical thirds examined. SEM digital photomicrographs were taken at ×1000 magnification to evaluate the amount of smear layer in each root canal third. CUI was more effective in removing the smear layer than the other irrigation protocols. However, none of the irrigation protocols were able to produce root canals completely free from smear layer.

Effect of Passive Ultrasonic Irrigation over Organic Tissue of Simulated Internal Root Resorption

This study aimed to evaluate the efficacy of passive ultrasonic irrigation (PUI) on dissolving the organic tissue inside simulated internal root resorption (IRR) using sodium hypochlorite (NaOCl) or chlorhexidine (CHX). A total of 40 human lower premolars were collected based on dimensional and morphological similarities. The roots were embedded in cylinders (3 cm diameter; 2.5 cm height) of self-cured acrylic resin, and then an IRR was simulated. The specimens were divided into 4 groups (n = 10) according to irrigation protocols: group 1: CHX + PUI; group 2: CHX; group 3: NaOCl + PUI; group 4: NaOCl. The total irrigation time was 150 s at a flow rate of 5 mL/min. A tissue mass of porcine palatine mucosa was used to simulate the organic tissue, it was weighed before and after the irrigation using an analytic balance, and the difference between both readings was calculated and transferred to percentage values. Data were submitted to statistical analysis using two-way ANOVA (factors: irrigant type and with/without PUI) and Tukey’s test for multiple comparisons among the experimental groups (α = 0.05). There was a significant difference in both factors (irrigant: p = 0.04 ; PUI: p ≤ 0.001 ). The groups that used PUI were more effective in dissolving the organic tissue of the IRR simulation than the groups without PUI. PUI is more effective than the syringe and needle irrigation in organic tissue dissolution.

Different biomechanical preparation protocols on the penetration and bond strength of the filling material to dentin

The aim of this study was to evaluate the influence of different instruments and mechanisms of agitation of the irrigating solution on the penetration by confocal laser scanning microscopy (CLSM), and the bond strength (BS) of the filling material to the dentin by push-out test. Human premolars were distributed in two experimental groups (n=30), according to the instrumentation system: ProTaper Next (PN) or XP-endo Shaper (XS) and three irrigation protocol (n=10): NaviTip (Nv), XP-endo Finisher (XF), passive ultrasonic irrigation/ XP-endo Finisher (PUIXF). The 2.5% NaOCl and 17% EDTA were the irrigating solutions used. The filling was performed using a lateral condensation technique, with AH Plus added to 0.1% rodhamine B. The roots were sectioned, obtaining 2 slices for each third of the root. The first slice was submitted to the sealer penetration analysis and the push-out test. The second slice was submitted to qualitative analysis (SEM) of the union interface. For the penetration (%) Tukey showed that PNXF (82.38±13.48), PNPUIXF (82.48± 12.02), XSXF (82.24±11.28) and XSPUIXP (86.23±10.45) presented the highest values, different (p<0.05) from PNNv (68.29±15.12) and XSNv (71.41±16.50). The BS (MPa) test evidenced that in the cervical third, PNPF (4.92±1.04) and XPSPF (5.03±0.70) obtained the highest values differing from the others groups (p<0.05). CSLM and SEM showed greater penetration of the sealer on the entire length of the root canal when the irrigation solution was stirred. In conclusion that the association PUI and XP-endo Finisher favored the penetration and bond strength of the filling material to the root dentin.