Ultrasonically Activated Irrigation Research Articles

Adjunctive Steps for the Removal of Hard Tissue Debris from the Anatomic Complexities of the Mesial Root Canal System of Mandibular Molars: A Micro–Computed Tomographic Study

IntroductionThis in vitro study sought to compare the efficacy of a sonic irrigant activation device with ultrasonic activation and needle irrigation in removing hard tissue debris (HTD) from anatomic complexities of the root canal system. MethodsTwenty-seven mesial roots of extracted human mandibular molars with 2 canals connected by an isthmus were selected based on micro–computed tomography scans (12-μm voxel size). The mesial canals were mechanically prepared to ProTaper Next X3 (Dentsply Maillefer, Ballaigues, Switzerland) and anatomically distributed into 3 groups (n = 9) according to the final irrigation protocol: sonically activated irrigation (SAI) using the EDDY system (VDW GbmH, Munich, Germany) for 3 × 20 seconds, ultrasonically activated irrigation (UAI) using a size 20 Irrisafe tip (Satelec Acteon, Mérignac, France) for 3 × 20 seconds, and conventional irrigation using a 30-G needle adapted to a syringe. Micro–computed tomographic scans were taken after instrumentation and after supplementary activation of the irrigant. After reconstruction and coregistration, the volume filled with HTD before and after irrigant activation was calculated, and the mean percentage of HTD reduction after final irrigation was compared within and among groups using the paired sample t test and 1-way analysis of variance post hoc Tukey test, respectively (α = 5%). ResultsA significant reduction in the volume filled with HTD after irrigant activation was observed in all groups (P < .05). The percentage reduction of HTD in the UAI group (66.8%) was significantly higher than that in the SAI group (36.4%) (P < .05), whereas the conventional irrigation group result (43.7%) did not differ statistically from the UAI or SAI groups (P > .05). ConclusionsAll tested supplementary irrigation steps significantly reduced the amount of debris created during root canal preparation. Ultrasonic activation resulted in the highest mean debris reduction.

Micro-CT study on the removal of accumulated hard-tissue debris from the root canal system of mandibular molars when using a novel laser-activated irrigation approach.

To compare the efficacy of ultrasonically activated irrigation (UAI), photon-induced photoacoustic streaming (PIPS) and shock wave enhanced emission photoacoustic streaming (SWEEPS) activation for the removal of accumulated hard-tissue debris (AHTD) from the root canal system of mandibular molars when assessed using microcomputed tomography (micro-CT). A total of 30 mandibular first and second molars with joining mesial root canals containing an isthmus and a single distal canal were subjected to three micro-CT scans (before and after canal instrumentation and after final irrigation) at a resolution of 15μm. Mesial canals were prepared up to aProTaper F3 rotary file, and distal canals were prepared up to aProTaper F4 rotary file. Teeth were randomly assigned to three groups according to the irrigant activation method (n=10): the UAI group, the PIPS group and the SWEEPS group. The final irrigation procedures were performed using a total of 15.5mL of 1% NaOCl for each tooth with an activation time of 3×30s. After three-dimensional model reconstruction and volumetric measurement of root canals, the percentage reduction (%Rd) of AHTD was calculated. The %Rd of AHTD was analysed statistically using one-way analysis of variance and nonparametric tests at a significance level of 5%. There were no significant differences between the three groups in terms of canal volume before or after instrumentation, or the volume of debris after canal preparation (P>0.05). In the mesial canals, irrigation with SWEEPS reduced the overall debris by 84.31%, which was significantly more than the reduction associated with PIPS and UAI (58.79% and 50.27%, respectively). In the distal canals, the %Rd of AHTD was significantly different between PIPS and SWEEPS and between UAI and SWEEPS (P<0.05), but was not significantly different between PIPS and UAI groups (P>0.05). The SWEEPS was associated with a greater %Rd of AHTD than the PIPS and UAI groups. SWEEPS was associated with significantly less debris compared than PIPS and UAI, especially in isthmus-containing mesial roots. None of the activation techniques completely removed debris from root canal systems.

The efficacy of ultrasonic and PIPS (photon-induced acoustic streaming) irrigation to remove artificially placed dentine debris plugs out of an artificial and natural root model.

The aim was to validate an artificial resin 'root canal wall groove model' (RCWGM) mimicking the situation of natural roots with a groove of identical dimensions on debris removal out of these grooves, and to evaluate Erbium 'laser-activated irrigation' (LAI) with two conical tips at PIPS (photon-induced photoacoustic streaming) settings, with different activation times and different root canal positions on debris removal out of the grooves. A split RCWGM was used (resin blocks and roots of maxillary canines) with a canal size 40/0.06. The grooves in the apical third were filled with stained dentinal debris. Seventeen irrigation protocols (n = 20) were used: syringe-needle irrigation (3× 20 s), manual dynamic activation (1× 60 s), ultrasonically activated irrigation (UAI) with 25/25 Irrisafe (3× 20 s) and LAI (2940 nm Er:YAG) with X-Pulse or PIPS tips at PIPS settings (20 mJ, 50 μs, 20 Hz) and with the fibre (IN) or (OUT) the canal: IN during 1× 20 s, and OUT during 1× 20 s, 2× 20 s, 3× 20 s, 30 s, 2× 30 s and 1× 60 s. The quantity of remaining dentine debris in the groove was evaluated on a numerical scale. Statistical analysis was performed by means of proportional odds logistic regression, equivalence testing and Wald tests. The level of significance was set at 0.05. Resin models and the RCWGM with natural teeth can be called equivalent (log odds ratio 0.185). There were mostly no statistically significant differences for debris removal between UAI and LAI (p > 0.05) and between LAI with PIPS and X-Pulse (p > 0.05). Although not statistically different, the numbers of completely cleaned grooves were higher with LAI than with UAI for a 1-min activation, confirming findings from other studies. There is no difference in cleaning efficacy between X-Pulse and PIPS tips at PIPS settings.

Influence of apical preparation size and irrigation technique on root canal debridement: a histological analysis of round and oval root canals

To examine the debridement of round and oval root canals prepared to two apical sizes with and without ultrasonically activated irrigation. Mandibular premolars with round (n=48) and oval (n=48) root canals were pair-matched after microCT scanning and randomly divided into two experimental groups (n=20): group 1, rotary NiTi to size 20, .04 taper; group 2, rotary NiTi to size 40, .04 taper. Specimens were subdivided into two subgroups (n=10): subgroup A, syringe and needle (SNI); subgroup B, ultrasonically activated irrigation (UAI). Untreated canals (eight oval and eight round) served as controls. Specimens were processed for histological evaluation for measurement of the remaining pulp tissue and debris (RPT), and the perimeter percentage of root canal area untouched by the instruments (PRAU). Following assessment of normality, multiple-way anova models were used to study the effects of preparation size, irrigation technique and canal cross-sectional shape, and their interactions on the RPT and PRAU (α=0.05). All experimental groups had significantly less RPT than the control (P<0.05). Both the preparation size (20 vs. 40) and the irrigation technique (SNI vs. UAI) had a significant effect on RPT (P=0.006 and P<0.001, respectively). Groups irrigated with SNI always had significantly greater RPT than those irrigated with UAI, irrespective of the preparation size (P<0.001). Canals prepared to size 20 had significantly greater RPT than those with size 40 in the SNI subgroup (P<0.001), but there was no significant difference in the UAI subgroup (P=0.481). Root canals prepared to a larger size (40) were cleaner than those prepared to a smaller size (20), when irrigation was performed with a syringe and needle. When the irrigant was ultrasonically activated, smaller preparations resulted in canals that were as clean as larger preparations. This finding was common to both round and oval canals of freshly extracted premolars with vital pulp tissue.

Micro-CT evaluation of sonically and ultrasonically activated irrigation on the removal of hard-tissue debris from isthmus-containing mesial root canal systems of mandibular molars.

To evaluate the efficacy of sonically and ultrasonically activated irrigation on removal of accumulated hard-tissue debris (AHTD) in mesial root canal systems of mandibular molars using micro-computed tomographic (micro-CT) analysis. Forty mesial roots of mandibular molars with two independent canals joined apically by an isthmus (Vertucci type II) were selected. The root canals were instrumented using Reciproc R25 instruments, and specimens were scanned at a resolution of 10.5μm. Subsequently, n=10 roots were assigned to each of the four final irrigation groups such that the group means and variances were almost identical: sonically activated irrigation with EndoActivator (EA) or EDDY (ED), ultrasonically activated irrigation (UAI) and manual irrigation without activation (MI). The final irrigation procedures were performed using a total of 5mL 1% NaOCl and 5mL 15% EDTA per canal over 5 min with activation time of 4×20 s. Reconstructed data sets were coregistered, and the mean percentage reduction of AHTD after final irrigation was compared statistically between groups using analysis of variance at a significance level set at 5%. A significant reduction of AHTD was achieved after final irrigation in all groups (P<0.05), ranging from 44.1% to 66.8%. The vol% of debris after irrigation was 3.7±1.9% for EA, 3.3±2.3% for ED, 2.1±1.6% for UAI and 4.4±2.3% for MI, with no significant difference between groups (P>0.05). None of the final irrigation protocols completely removed AHTD from mesial root canal systems in extracted human mandibular molars. Sonically and ultrasonically activated irrigation performed no better compared to manual irrigation.

Efficacy of sonically, ultrasonically and laser‐activated irrigation in removing a biofilm‐mimicking hydrogel from an isthmus model

To evaluate the efficacy of sonically, ultrasonically and laser-activated irrigation (LAI) in removing a biofilm-mimicking hydrogel from the isthmus in a root canal model. Transparent resin blocks containing two standardized root canals (apical diameter of 0.3mm, 6% taper, 16mm long, with a coronal reservoir) connected by an isthmus (0.15mm wide, 2mm high) were used as the test model. The isthmus was filled with a hydrogel-containing dentine debris. The canals were filled with irrigant, and the models were randomly assigned to the following activation groups (n=20): EndoActivator (EA), Eddy, ultrasonically activated irrigation (UAI) with an Irrisafe 25mm length, size 25 file and LAI with a 2940nm Er:YAG-laser (20Hz, 50μs, 20mJ, PIPS tip at the canal entrance). All protocols were executed for 3×20s. Needle irrigation (NI) with a 27G needle served as the control. Standardized images of the isthmus were taken before and after irrigation, and the amount of removed hydrogel was determined using image analysis software and compared across groups using Welch anova (P≤0.05). Hydrogel removal was greatest in the LAI group (90.2%) and was significantly greater than that with UAI, EA and NI (P≤0.014), but not significantly different from Eddy (P=0.498). Hydrogel removal with Eddy (85.9%) was significantly greater than that with NI and EA (P<0.05), but not significantly different from UAI (P=0.07). There was no significant difference between the NI and EA groups (P=1). Laser-activated irrigation and Eddy resulted in the greatest hydrogel removal and performed better than EA and UAI. The effect of LAI was also not dependent on deep intracanal tip placement.

Effectiveness of irrigation strategies on the removal of the smear layer from root canal dentin.

The aim of this study was to evaluate the removal of the smear layer by some commonly used (needle-and-syringe irrigation, sonic activation, ultrasonically activated irrigation) and new root canal irrigation strategies (negative pressure irrigation and polymer rotary file) using a novel approach by comparing pre- and post-experimental images. Prepared root canals (n = 50) were subjected to a split tooth model and divided into 5 groups (n = 10): (1) needle-and-syringe irrigation (control); (2) sonic activation (SA); (3) negative pressure irrigation with continuous warm activated irrigation and evacuation (CWA); (4) polymer finishing file (FF); (5) ultrasonically activated irrigation (UAI). Smear layer scores and percentage of open dentinal tubules (%ODT) were evaluated by 2 examiners before and after irrigation procedures, from the middle and apical thirds of the root canal, on scanning electron microscopic images. Data were analysed using Kruskal-Wallis and post hoc tests at P = 0.05. Needle-and-syringe irrigation (control) showed no significant difference (both smear score and %ODT) compared to the pre-experimental value (P > 0.05). All other groups showed lower smear scores and higher %ODT, compared to the control (P < 0.05). The lowest smear score and highest %ODT were observed in the CWA group, which was significantly different from all other groups (P < 0.05). SA group showed significantly higher smear scores and lower %ODT than FF or UAI (P < 0.05). CWA showed superior removal of smear layer in the middle and apical thirds of the root canal compared to the other irrigation strategies.

Effectiveness of ultrasonically activated irrigation on root canal disinfection: a systematic review of in vitro studies.

Reduction of microbial load from the root canal systems is a pre-requisite for healing of lesions of endodontic origin. Such microbial reduction is influenced by the method of irrigant delivery and activation. The aim of this systematic review was to compare the effect of ultrasonically activated irrigation (UAI) with other irrigation techniques on the reduction of microorganisms during root canal disinfection. The research question was created based on the PICO strategy. Two reviewers independently performed a comprehensive literature search in electronic databases. Following application of inclusion and exclusion criteria to the selected articles, a systematic data extraction sheet was constructed. The selected articles were assessed using methodological quality scoring protocol. The risk of bias in selected studies was critically assessed by two reviewers. A total of 15 articles were included for the systematic review. The included studies were heterogeneous in study design; hence, meta-analysis was not performed. The overall risk of bias for the selected studies was moderate. Overall, UAI showed superior reduction of microbial counts, resulting in better disinfection compared to other irrigation systems chosen for comparison in this review. The use of UAI can bring about superior microbial reduction within the root canal system compared to other irrigant activation techniques. Activation of irrigants with ultrasonic brings about significant bacterial reduction from the root canal systems compared to other methods of irrigant activation and conventional syringe irrigation. This might help in improving the outcome of root canal treatment.

Hard tissue debris removal from the mesial root canal system of mandibular molars with ultrasonically and laser-activated irrigation: a micro-computed tomography study.

This study is to investigate the efficacy of different irrigant activation techniques on removal of accumulated hard tissue debris (AHTD) in mesial roots of human mandibular molars. Extracted human mandibular molars with an isthmus between the mesial root canals were selected based on micro-CT (μCT) scans. The mesial canals were instrumented to an apical diameter ISO30 using ProTaper rotary files. Teeth were randomly assigned to three irrigant activation groups (n=10): ultrasonically activated irrigation (UAI) using a size 20 Irrisafe for 3×20s, laser-activated irrigation (LAI) with an Er:YAG laser (2940nm) and plain 300μm fiber tip inside the canal (20mJ, 20Hz, 3×20s), and laser-activated irrigation with identical parameters with a 400μm photon-induced photoacoustic streaming (PIPS) tip held at the canal entrance. All teeth were scanned with μCT before and after instrumentation and after irrigant activation. After reconstruction and image processing, the canal system volume filled with hard tissue debris before and after irrigant activation was calculated. Changes in hard tissue debris volumes were compared between groups using one-way ANOVA. The percentage volume of hard tissue debris (vol%) was significantly lower after irrigant activation in all groups. Although the lowest debris values were observed in the laser groups, no significant differences in the vol% of accumulated hard tissue debris after activation were observed between groups. Accumulated hard tissue debris was reduced significantly in all activation groups. Ultrasonically and laser-activated irrigation regimens performed similarly in this respect. None of the tested methods was able to render the root canal systems free of debris.

A novel model for testing the efficiency of removal of calcium hydroxide from complex root canal anatomies.

The purpose of this study was to evaluate the efficacy of several irrigation protocols in the removal of calcium hydroxide [Ca(OH)2 ] from simulated internal root resorption cavities in a complex root canal anatomy model. The 20° to 35° curved mesiobuccal roots of 94 maxillary molars were sectioned longitudinally; internal resorption cavities were prepared in the apical third of the canal walls. Calcium hydroxide was placed into the cavities and the root halves reassembled. Four teeth were used as controls, and 90 teeth were randomly divided into six experimental groups (n = 15), according to the irrigation protocols used: syringe irrigation; H2 O2 (HP); Navitip FX; Vibringe-syringe; Vibringe-NaviTip FX; ultrasonically activated irrigation (UAI) using an ultrasonic K-file. In the HP group, 2.5% NaOCl and 3% H2 O2 were used, while 2.5% NaOCl and 17% EDTA were used in the remaining groups. Stereomicroscope images and radiographs were used to measure the remaining Ca(OH)2 . The model proved to be suitable for simulating complex anatomy. Positive correlation was found between stereomicroscope and radiographic analyses (P < 0.05). UAI removed significantly more Ca(OH)2 than the other experimental groups (P < 0.05). The HP group was the least efficient protocol (P < 0.05). It would appear that a reliable model has been developed that simulates complex root canal anatomy. Irrigant activation protocols enhanced Ca(OH)2 removal.

The use of auxiliary devices during irrigation to increase the cleaning ability of a chelating agent.

ObjectivesThis study investigated the cleaning ability of ultrasonically activated irrigation (UAI) and a novel activation system with reciprocating motion (EC, EasyClean, Easy Equipamentos Odontológicos) when used with a relatively new chelating agent (QMix, Dentsply). In addition, the effect of QMix solution when used for a shorter (1 minute) and a longer application time (3 minutes) was investigated.Materials and MethodsFifty permanent human teeth were prepared with K3 rotary system and 6% sodium hypochlorite. Samples were randomly assigned to five groups (n = 10) according to the final irrigation protocol: G1, negative control (distilled water); G2, positive control (QMix 1 minute); G3, QMix 1 minute/UAI; G4, QMix 1 minute/EC; G5, QMix 3 minutes. Subsequently the teeth were prepared and three photomicrographs were obtained in each root third of root walls, by scanning electron microscopy. Two blinded and pre-calibrated examiners evaluated the images using a four-category scoring system. Data were statistically analyzed using Kruskal-Wallis and Dunn tests (p < 0.05).ResultsThere were differences among groups (p < 0.05). UAI showed better cleaning ability than EC (p < 0.05). There were improvements when QMix was used with auxiliary devices in comparison with conventional irrigation (p < 0.05). Conventional irrigation for 3 minutes presented significantly better results than its use for 1 minute (p < 0.05).ConclusionsQMix should be used for 1 minute when it is used with UAI, since this final irrigation protocol showed the best performance and also allowed clinical optimization of this procedure.