Ultrasonically Activated Irrigation Research Articles

The efficacy of a novel SWEEPS laser-activated irrigation compared to ultrasonic activation in the removal of pulp tissue from an isthmus area in the apical third of the root canal.

This study aimed to evaluate the efficacy of Shock Wave Enhanced Emission Photoacoustic Streaming (SWEEPS) in the removal of remaining pulp tissue from the root canal isthmus area in lower molars and compare it with ultrasonically activated irrigation (UAI) and conventional needle irrigation (NI). Forty-one lower molars with isthmuses between mesial canals were included in the study. The teeth were randomly distributed into experimental groups (n = 12/each) based on the final irrigation protocol (SWEEPS, UAI, or NI) and a control group (C) (n = 5). The traditional access cavity of the mesial part of each tooth was made in all samples. The mesial root canals in the experimental groups were instrumented with a Wave One Gold Primary (25/.07) file using 3% sodium hypochlorite (NaOCl) while the distal canal served as a control for the presence of pulp tissue. No treatment was performed in the C group. Sections from the isthmus region were processed for histopathology to measure the remaining pulp tissue (RPT). The results were analyzed using analysis of variance and the Kruskal-Wallis test (α = 0.05). There were no significant differences in the relative surface area of root canals and isthmus among the groups (p > 0.05). Samples in the SWEEPS group had significantly less RPT than UAI, NI, and C (p = 0.003, 0.014, 0.003, respectively). There were no significant differences between the UAI and NI (p = 0.583). SWEEPS was the most efficient in debridement of the root canal isthmus area. UAI and NI showed similar but lower efficiency.

Cleaning Efficiency of Different Irrigation Techniques in Simulated Severely Curved Complex Root Canal Systems

IntroductionTo compare the biofilm-mimicking hydrogel removal efficiency of laser-activated irrigation (LAI) with five other irrigation techniques in simulated curved root canals with lateral canals. MethodsThree-dimensional–printed root canal models (60°-curvature, radius 5 mm; dimension 25/.06) with a total length of 20 mm and lateral canals in all directions at 2, 5, and 8 mm (diameter 0.2 mm) from the apex were filled with a colored biofilm-mimicking hydrogel. The following protocols (each 3 × 20 seconds continuous irrigation with distilled water 3 ml/20 seconds; n = 20) were carried out: conventional needle irrigation; manual agitation ([MA], gutta-percha point 25/.06); EndoActivator (=sonically-activated irrigation EndoActivator, 25/.04); EDDY (=sonically-activated irrigation EDDY [SAI-E]; 25/.04); ultrasonically-activated irrigation and LAI (Erbium-doped Yttrium Aluminum Garnet laser; P400FL tip at canal entrance; 25 pps, 50 mJ, 300 μs). Standardized photos were taken with a microscope and the removal of the hydrogel was determined as a percentage for the entire system, the main canal and the lateral canals. Statistical analysis was performed using analysis of variance and Scheffé test (P = .05). ResultsLAI (89.3% ± 5.9%) showed the greatest hydrogel removal followed by SAI-E (65.5% ± 3.3%) and ultrasonically-activated irrigation (59.1% ± 4.7%), with significant differences between these groups (P < .05). Needle irrigation, MA, and sonically-activated irrigation EndoActivator performed equally (P > .05) and obtained the significantly lowest values (P < .05). LAI and SAI-E showed the significantly best hydrogel removal from the main canal (P < .05). At all three levels, LAI removed significantly more hydrogel from the lateral canals than all other techniques (P < .05). ConclusionsLAI was superior to other techniques in both the entire system and the lateral canals in removing the hydrogel. SAI-E achieved comparable results in the main canal.

Efficacy of a novel remotely-generated ultrasonic root canal irrigation system for removing biofilm-mimicking hydrogel from a simulated isthmus model.

To evaluate the efficacy of a novel ultrasonic irrigation device, remotely-generated irrigation with a non-invasive sound field enhancement (RINSE) system, in removing biofilm-mimicking hydrogel from a simulated isthmus model and compare it with sonically- and ultrasonically-activated irrigation systems. A polycarbonate root canal model containing two standardized root canals (apical diameter of 0.20 mm, 4% taper, 18 mm long with a coronal reservoir) connected by three isthmuses (0.40 mm deep, 2 mm high, 4 mm long) was used as the test model. The isthmuses were filled with a hydroxyapatite powder-containing hydrogel. The canals were filled with irrigant, and the models were randomly assigned to the following activation groups (n=15): EndoActivator (EA), ultrasonically activated irrigation (UAI), and RINSE system (RS). Syringe irrigation (SI) with a 30G needle served as the control. Standardized images of the isthmuses were taken before and after irrigation, and the amount of hydrogel removed was determined using image analysis software and compared across groups using anova (p < .05). Hydrogel removal was significantly higher with the RS (83.7%) than with UAI, EA, or SI (p ≤ .01). UAI (69.2%) removed significantly more hydrogel than SI and EA (p < .05), while there was no significant difference between SI (24.3%) and EA (25.7%) (p=.978). RINSE system resulted in the most hydrogel removal, performing better than UAI or EA. The effect of RS was also not reliant on the insert or tip entering the pulp chamber or root canal, making it particularly useful in conservative endodontics.

IMPACT OF THE PASSIVE/ACTIVE ULTRASONIC ACTIVATION ON THE ENDODONTIC IRRIGANTS EFFECTIVENESS - A REVIEW

Introduction: various irrigation devices and chemical solutions are being developed and improved nowadays for better penetration deep into the complex root canal system. Activation of irrigating solutions enhances the solution effectiveness. Evidence in the literature suggests that ultrasonic irrigation is much more effective in this respect than syringe irrigation alone. Passive ultrasonic irrigation (PUI) and/or ultrasonically activated irrigation (UAI): nowadays, the two terms, PUI and UAI, are interchangeable in the literature and represent the same technique. Literature data have shown that combining ultrasonically activated NaOCl with EDTA results in significantly greater removal of the smear layer. Conclusion: the use of ultrasonic activation of the irrigating solution after root canal preparation significantly improves the removal of debris from hard-to-reach areas such as isthmuses, lateral canals and the apical delta.

The Efficacy of Er:YAG Laser-Activated Shock Wave-Enhanced Emission Photoacoustic Streaming Compared to Ultrasonically Activated Irrigation and Needle Irrigation in the Removal of Bioceramic Filling Remnants from Oval Root Canals-An Ex Vivo Study.

The removal of filling material is important for successful root canal retreatment. The aim of the study was to compare the efficiency of two activated irrigation techniques, the shock wave-enhanced emission photoacoustic streaming (SWEEPS) mode of the Er:YAG laser and ultrasonically activated irrigation (UAI) and a conventional syringe-needle technique (SNI), in the removal of bioceramic sealer/gutta-percha during conventional retreatment in oval root canals. The study sample consisted of distal root canals of 42 extracted human mandibular molars, which were prepared using a ProTaper Next system up to size 40/0.06 and filled with bioceramic sealer using a single-cone obturation technique. The teeth were then re-treated with a Reciproc Blue RB40 file and 3% sodium hypochlorite solution. The prepared teeth were randomly divided into three groups (n = 14 per group) and subjected to one of the three irrigation methods. Micro-CT scans were performed at different stages to assess the amount of filling material after each retreatment phase. The results of the study showed that all the tested irrigation techniques reduced a statistically significant amount of the remnant filling material at retreatment (p &lt; 0.05), and there were no statistically significant differences in efficacy between the three methods. All tested techniques had similar efficacy in the removal of the remaining filling remnants.

Effectiveness of adjunct therapy for the treatment of apical periodontitis: A systematic review and meta-analysis.

Adjunct therapy refers to any intracanal procedure going beyond chemomechanical preparation with instruments and traditionally delivered irrigants (excluding interim dressings). It is not clear whether and which of these adjunct therapies have a significant impact on the outcome of root canal treatment [healing of apical periodontitis (AP) and other patient-related outcomes]. This systematic review aimed to analyse available evidence on the effectiveness of adjunct therapy for the treatment of AP in permanent teeth, according to a population, intervention, comparison, outcome, time and study design framework formulated a priori by the European Society of Endodontology. Five electronic databases (PubMed, Embase, Scopus, Cochrane and Web of Science) were searched up to October 2021 to identify clinical studies comparing adjunct therapy to no adjunct therapy in adult patients with AP. Animal studies, reviews, studies with less than 10 patients per arm and studies with a follow-up time of less than 1year, or less than 7 days for postoperative pain, were excluded. The quality of the included studies was appraised by the appropriate tools [Risk of Bias 2 (RoB2) for randomized clinical trials (RCTs) and Newcastle-Ottawa Scale for observational studies]. Meta-analysis was performed using a random-effects model. The certainty of the evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. Fourteen studies (13 RCTs and one retrospective cohort) fulfilled the inclusion criteria for this review. They evaluated different types of adjunct therapy: antimicrobial photodynamic therapy (aPDT; three studies), diode laser canal irradiation (3), Nd:YAG laser canal irradiation (2), Er;Cr:YSGG laser canal irradiation (1), ozone therapy (2) and ultrasonically activated irrigation (UAI) (4). Radiographical healing was reported in seven studies, but meta-analysis was only possible for UAI (two studies), showing no statistically significant difference in healing after 12 months. Pain after 7 days was reported in seven studies. Meta-analysis on three studies that used aPDT and on two studies using diode laser irradiation showed no significant difference in the prevalence of pain after 7 days between the control and adjunct therapy. According to RoB2 tool, six studies had a high risk of bias, five studies had some concerns, and two studies low risk of bias. The GRADE assessment revealed a very low strength of evidence for diode laser, and low strength of evidence for PDT, ozone and UAI studies. The included studies displayed significant heterogeneity in terms of type of adjunct therapy, technical details per adjunct therapy, outcome reporting and several combinations of these, limiting the potential for meta-analysis. There is insufficient evidence to recommend any adjunctive therapy for the treatment of apical periodontitis. Prospero CRD42021261869.

Does ultrasonic activation of irrigation during endodontic therapy improve the clinical and microbiological effects?

Data sources A comprehensive collection of databases were searched from inception to August 2020, such as Cochrane, MEDLINE, Scopus and Web of science. Also, references and citations of retrieved records, conference proceedings and leading journals were searched.Study selection All randomised clinical trials on root-canal-treated adult permanent teeth that compared the outcomes of ultrasonically activated irrigation (UAI) to syringe irrigation (SI) were eligible. The outcomes considered were post-operative pain, pain intensity, periapical healing after 12 months, the incidence of microbial presence, microbial quantification, lipopolysaccharides (LPS) quantification and lipoteichoic acid quantification. Studies with insufficient data for risk of bias assessment or other outcomes were excluded.Data extraction and synthesis The two independent reviewers did the screening process in title, abstract and full-text assessment steps. Also, the data extraction process and risk of bias assessment were done by two independent reviewers. Any disagreement was resolved by consensus or the opinion of a third reviewer. Any missing information was filled in by contacting the authors. The Cochrane risk-of-bias tool for randomised trials was used to assess the risk of bias. The following domains were evaluated for risk of bias: randomisation process, deviation from the intended interventions, missing outcome data, outcome measurement and the selection of the reported results. If all domains were rated as 'low risk', judgements would be rated as 'low risk', otherwise, 'high risk'. The risk ratios and mean risk difference with 95% confidence interval (CI) were used as measure effect. The random effects model was used to combine the effects. The heterogeneity is measured by I2 test (I2 test >50% and p <0.1 considered as substantial heterogeneity). The level of certainty of evidence for clinically important outcomes was determined using the guidelines of Grading of Recommendations Assessment, Development and Evaluation working group.Results Four studies entered the meta-analysis stage based on pain outcomes. The overall risk of bias for three of them was assessed as high. All of them had examined pain incidence before 24 hours but only two studies have examined the occurrence of pain in the period of 24-72 hours and after 72 hours to 7 days. Considerable heterogeny was among the incidence of pain <24 hours between studies (I2= 83%). Therefore, the incidence of pain in two sub-groups of vital and non-vital pulp has been investigated. In the non-vital pulps, the incidence of pain by UAI was half of the incidence of SI pain (relative risk= 0.50; 95% CI 0.35-0.71; I2 = 0%; 308 teeth). But no significant difference was seen in vital pulps. Also, there was no significant difference in the occurrence of pain after 72 hours between the two methods. Two studies assessed the intensity of pain in three periods: <24 hours, 72-24 hours, more than 72 hours and less than 7 days. The combined results based on vital and non-vital groups resulted in no significant difference in any period. Pooled data of pain outcomes were assessed with very low or low confidence of evidence.Five studies with microbiology-related outcomes entered the final analysis stage. The overall risk of bias for two of them was high. Three studies evaluated the effect of the irrigation method on microbial presence as an outcome. High heterogeneity was among the results of the studies (I2= 72%). However, with and without subgroup analysis, meta-analysis results showed no significant difference between these two methods. A lower microbial count was found with UAI than SI in a meta-analysis of four studies (standardised mean difference-pooled - 0.40; 95% CI [-0.78, -0.02]; I2 = 0%; 126 teeth). Two studies measured LPs. The meta-analysis showed lower values of LPS with UAI compared to SI (34, 37) (mean difference pooled - 0.06; 95% CI [-0.11, -0.01]; 61 root canals; I2 = 29%). One study measured lipoteichoic acid and found no significant difference between the irrigation methods.Three studies with treatment-success-related outcomes entered the meta-analysis stage with an overall high risk of bias. Two studies' pooled data revealed no significant difference between the irrigation methods regarding treatment failure. One study assessed periapical-lesion volume after treatment and found no significant difference between the irrigation methods.Conclusions According to limited data, UAI may reduce the risk of post-operative pain during the first 24 hours and reduce microbial counts, particularly cultivable germs in cases of apical periodontitis. However, most meta-analyses are conducted on a small number of studies and have an overall 'very low' to 'low' certainty of evidence; as a result, the evidence is deemed insufficient to either support or disprove UAI efficacy when compared to SI.

Effect of photon-induced photoacoustic streaming and shock-wave enhanced emission photoacoustic streaming technique on the removal of the smear layer after root canal preparation in curved root canals

The efficiency of root canal irrigation has an important impact on the prognosis of root canal treatment. Photon-induced photoacoustic streaming (PIPS) and shock wave enhanced emission photoacoustic streaming (SWEEPS) are the special modality of Er: YAG laser, whether can they improve the efficiency of root canal irrigation remains to be studied. Fifty human teeth with curved root canals were collected and stored in the thymol solution until used in the study. After traditional endodontic cavities preparation, root canals were prepared to size #35 with a 0.04 taper. The final irrigating techniques were as follows: (I) manual dynamic activation (MDA), (II) ultrasonically activated irrigation (UAI), (III) sonically activated irrigation (SAI), (IV) PIPS, and (V) SWEEPS. Fifty teeth were randomly divided into five groups mentioned above. After root canal preparation, the roots were cleaved longitudinally. The dentine surfaces were photographed from the coronal, middle, and apical third of the root by scanning electron microscopy operated at a low vacuum. Two examiners separately graded each image according to the remained smear layer situations. PIPS and SWEEPS groups showed fewer smear layers remaining than the others in the middle and the apical third (P< 0.05) of the root canal. In contrast, in the coronal third, five groups showed no significant difference (P>0.05). PIPS and SWEEPS showed superior smear layer clearing efficiency than traditional irrigating techniques in curved root canals.

Impact of agitation/activation strategies on the antibiofilm potential of sodium hypochlorite/etidronate mixture in vitro

BackgroundTo investigate the effect of a rotary agitation method or ultrasonically activated irrigation on the antibiofilm effect of a mixture of sodium hypochlorite (NaOCl) and etidronate (1-hydroxyethylidene-1,1-bisphosphonate, HEBP) using a dual-species biofilm model in root canal system.MethodsMature dual-species biofilms of Enterococcus faecalis and Streptococcus gordonii were formed in root canals of mandibular premolars. Teeth were randomly allotted (n = 12) to group 1, XP-endo Finisher (XPF); group 2, ultrasonically activated irrigation (UAI); group 3, syringe-and-needle irrigation (SNI). In all groups, canals were instrumented with a rotary instrument (XP-endo Shaper) prior to irrigant agitation/activation. A mixture containing 2.5% NaOCl and 9% HEBP was used throughout the experiment. Bacterial counts from the canal were determined using qPCR before preparation (S1), after preparation (S2), and after final irrigation agitation/activation (S3). Bacterial viability within the dentinal tubules in the coronal, middle and apical root-thirds was quantified using confocal microscopy after Live/Dead staining. The bacterial counts and viability were compared between groups using one-way ANOVA and post-hoc Tukey’s tests. Paired t-test was used to compare the bacterial counts within groups.ResultsInstrumentation alone could significantly reduce the microbial counts in all the groups (P < 0.0001). Subsequent agitation/activation resulted in significant microbial reduction only in XPF and UAI (P < 0.05), both of which reduced significantly more microbial counts than SNI (P < 0.05). Live/Dead staining revealed that XPF and UAI showed significantly greater percentage of dead bacteria within the dentinal tubules than SNI in the coronal third (P < 0.05); UAI resulted in the significantly highest percentage of dead bacteria in the middle third (P < 0.05); while there was no significant difference between the groups in the apical third (P > 0.05).ConclusionsWhen using the sodium hypochlorite/etidronate mixture for irrigation, final irrigant agitation/activation with XP-endo Finisher or ultrasonic can improve disinfection of the main root canal space and the dentinal tubules in the coronal third, while ultrasonically activated irrigation appears to exhibit better disinfection within dentinal tubules in the middle third.

Assessment of the Effectiveness of Supplementary Methods for Residual Filling Material Removal Using Micro-computed Tomography: A Systematic Review and Meta-analysis of In Vitro Studies.

A systematic review and meta-analysis were conducted to evaluate the effectiveness of auxiliary methods in removing residual filling material (RFM). This systematic review has been registered with the International Prospective Register of Systematic Reviews (registration number CRD42020197482). A comprehensive literature search was conducted to identify relevant articles in electronic databases (PubMed, Embase, Cochrane) from January 2005 to March 2021. In vitro studies investigating or comparing at least one type of supplementary method or technique were included. A total of 26 studies were selected from the 239 records obtained after screening the databases. Ten of the included studies were suitable for meta-analysis. Strong evidence showed that ultrasonically activated irrigation (UAI) [SMD (95% CI): -0.52 (-0.88 to -0.16, P=0.266)] and XP-Endo Finisher R (XPR) [SMD (95% CI): -0.55 (-0.89 to -0.20, P=0.136)) contributed significantly to increase the removal procedure, and XPR has no significant superiority over UAI [SMD (95% CI): 0.36 (-0.12 to 0.84, P=0.994)]. Strong evidence was found to support the increased cleaning efficiency of the supplementary use of the Gentle Wave system, laser irradiation, XP Endo Finisher, and self-adjusting file. In contrast, conflicting evidence was found to support the use of sonic to improve the removal of RFM, and limited evidence was found to support the efficiency of Tornado Brush. Under in vitro conditions, UAI and XPR increase the removal of RFM from the root canal system during retreatment procedures.

Novel laser activated photoacoustic streaming for removing pulp remnants from round root canals after single file reciprocating instrumentation

Background: This study evaluated the efficacy of a new laser-assisted irrigation system, the shock wave enhanced emission photo-acoustic streaming (SWEEPS) technique in removing pulp tissue from single-rooted premolars. Methods: Freshly extracted mandibular premolars with round root canals (n = 40), scanned using cone beam computed tomography, were randomly divided into control and four experimental (according to the irrigation technique used) groups (n = 8/group). Groups 1, 2, and 3 were instrumented using Reciproc Blue (RB25/0.06) followed by final irrigation protocol (FIP), activated by SWEEPS, ultrasonically activated irrigation (UAI), and conventional irrigation (CI), respectively. In these groups, 7 mL 3% NaOCl in total was used during instrumentation; for FIP, 3% NaOCl (60 s), ethylenediaminotetraacetic acid (60 s), and 3% NaOCl (30 s). In group 4, SWEEPS activation of 3% NaOCl for 6 × 30 s alone was performed. The untreated control group specimens were processed for histological evaluation of remaining pulp tissue (RPT) in each canal third. The results were analyzed using the Mann-Whitney U test (α = 0.05). Results: Significant differences were observed between the control group and the experimental groups (p<0.05). In the middle third, the UIA and SWEEPS showed similar efficacy (p = 0.171), superior to CI and SWEEPS without instrumentation (p<0.05). In the apical third, SWEEPS was the most efficient (p = 0.002), and UIA and CI showed no difference (p = 0.643). Conclusion: SWEEPS was superior to UIA and CI in removing RPT in the apical region of round canals after single instrument root canal preparation; SWEEPS without instrumentation was inefficient in removing pulp tissue.

Clinical and microbiological effects of ultrasonically activated irrigation versus syringe irrigation during endodontic treatment: a systematic review and meta-analysis of randomized clinical trials.

This study aimed to systematically review clinical and microbiology-related effects of ultrasonically activated irrigation (UAI) compared to syringe irrigation (SI) during endodontic treatment. Electronic databases searching and manual searching were conducted. Only randomized clinical trials (RCTs) were included comparing UAI to SI. The RoB 2.0 Cochrane tool was used for risk-of-bias (RoB) assessment. The main outcomes were postoperative pain, treatment failure, and microbiology-related outcomes. Qualitative and quantitative analyses, wherever applicable, were performed. Risk ratios (RR) and [standardized] mean differences {[S]MD} were calculated for dichotomous and continuous outcomes, respectively. Certainty of evidence (CoE) was assessed using GRADE tool. Ten RCTs were included. UAI reduced pain incidence within the first 24h (RR 0.50, 95% CI 0.35-0.71, 308 teeth) and microbial counts (SMDpooled -0.40, 95% CI [-0.78, -0.02], I2 = 0%, 126 teeth) than SI in non-vital teeth with apical periodontitis (AP). Both groups, however, had similar effects regarding pain intensity, lipopolysaccharide amounts, and the incidence of rescue-analgesic intake, treatment failure, and microbial presence (p > 0.05). CoE ranged from low to very low. Very limited evidence suggests that UAI could reduce postoperative-pain risk within the first 24h and microbial counts for non-vital teeth with AP compared to SI. Most meta-analyses, however, are based on very few studies, mostly low-powered, with an overall very-low-to-low CoE. Further well-designed, larger RCTs are, thus, required.

Influence of apical preparation size and final irrigation protocol on the debridement of oval root canals.

This study assessed the influence of apical preparation size and final irrigation protocol on the debridement of the apical third of oval root canals of mandibular molars. Seventy-seven distal roots were divided into 7 groups (n = 11): Control: without instrumentation or irrigation; Group 30CI: ProTaper Next (up to size 30; PTN) + conventional irrigation (CI); Group 30UAI: PTN + ultrasonically activated irrigation (UAI); Group 30XPF: PTN + XP-endo Finisher (XPF); Group 40CI: PTN + ProDesign Logic (up to size 40; PDL) + CI; Group 40UAI: PTN + PDL + UAI; and Group 40XPF: PTN + PDL + XPF. The total volume of irrigating solutions used per root canal in all the experimental groups was 33 mL of 2.5% sodium hypochlorite (NaOCl) and 6 mL of 17% ethylenediaminetetraacetic acid (EDTA). After specimen processing and histological analysis under a digital microscope (100x), the percentages of untouched canal walls (UCW) and remaining debris (RD) were assessed using Image J software. A descriptive and exploratory analysis was conducted, indicating that the data failed to meet the assumptions of an analysis of variance. Therefore, generalized linear models were used to assess the effects of the different instrumentation and irrigation protocols, as well as the interaction among them, on the percentage of UCW and RD. No significant difference was found among the irrigation protocols regarding the percentage of UCW, irrespective of apical preparation size (p>0.05). However, UCW and RD were significantly lower in groups 40CI, 40UAI and 40XPF than in groups 30CI, 30UAI and 30XPF (p<0.05). The percentage of RD was significantly lower in the UAI and XPF groups than in the CI groups, irrespective of apical preparation size (p<0.05). The difference between preparation sizes 30 and 40, with respect to RD, was higher when CI was used (p<0.05). In conclusion, instrumentation up to apical preparation size 40 resulted in lower percentages of UCW and RD than up to apical preparation size 30. Use of UAI or XPF resulted in lower percentages of RD than CI.

Apical pressures generated by several canal irrigation methods: A laboratory study in a maxillary central incisor with an open apex.

AimA laboratory study to determine the apical pressure generated by seven canal irrigation methods in an anterior tooth with an open apex.MethodologyCanal irrigation was performed on a 3D‐printed central maxillary incisor with an open apex (maximum diameter of 2.1 mm). Ultrasonically activated irrigation (UAI), sonic activation (EDDY), negative pressure irrigation (EndoVac), the self‐adjusting file (SAF) and the XP‐endo Finisher were employed at tooth length (TL), TL—1 mm, TL—2 mm and TL—3 mm. UAI was tested at three intensity levels additionally. Hydrodynamic irrigation with RinsEndo was performed in the pulp chamber, at the canal orifice, the coronal third, the middle of the canal and at TL. Er:YAG laser activation, at four frequency settings, was performed in the pulp chamber and at the orifice of the canal. The pressure of the fluid towards the canal terminus generated by activation was directly transferred to a pressure sensor with a range of 0 to 120 mmHg and a response time of ≤0.5 ms. The critical threshold for apical extrusion of the irrigant was set at 5.73 mmHg (lower limit of the central venous pressure: 5.88 ± 0.15 mmHg). Each experiment was repeated ten times. The tests were followed by descriptive analyses (maximum, mean, standard deviation, 95% confidence interval).ResultsEndoVac, the SAF, the XP‐endo Finisher, and UAI never exceeded the critical threshold at any insertion depth or intensity level. Er:YAG laser activation exceeded the critical threshold exclusively at frequency settings that varied from the manufacturer's recommendation. EDDY at TL and RinsEndo at any insertion depth exceeded the critical threshold in 100% of the measurements. EDDY at TL—1,—2, and—3 mm crossed the critical threshold in 30%, 10%, and 20% of the measurements, respectively.ConclusionsIn a simulated maxillary central incisor with an open apex, irrigation with EndoVac, Er:YAG laser activation, UAI, the SAF, and the XP‐endo Finisher generated apical pressures below the critical threshold of 5.73 mmHg. By contrast, using EDDY and RinsEndo for irrigation produced higher apical pressures that exceeded the critical threshold.

A novel three-dimensionally printed model to assess biofilm removal by ultrasonically activated irrigation.

To apply an innovative three-dimensionally printed tooth model to investigate the efficacy of three ultrasonically activated irrigation (UAI) systems in removing multispecies biofilms from dentine samples. Three-dimensionally printed teeth with a curved root canal were fabricated with a standardized slot in the apical third of the root to achieve precision fit of human root dentine specimens. Multispecies biofilms including Enterococcus faecalis, Streptococcus mitis and Campylobacter rectus were developed in the root canal for 21days. The canals were allocated to be irrigated with 1% sodium hypochlorite (NaOCl) using a syringe and needle or ultrasonically activated NaOCl with a stainless-steel file (Irrisafe), a conventional nickel-titanium (Ni-Ti) file (CK) or a blue heat-treated Ni-Ti file (Endosonic Blue). Infected root canals irrigated with distilled water served as controls. Bacterial reduction was determined by colony-forming unit (CFU) counting (n=20), whilst biofilms were analysed using confocal laser scanning microscopy (n=7) and field emission scanning electron microscopy. For CFU counting, the independent two-sample t-test (Welch's t-test) was examined to compare overall bacterial reduction amongst groups. For CLSM analysis, the data were analysed using one-way analysis of variance (ANOVA), followed by the Scheffé post hoc test. The p-values <.05 were considered to indicate statistical significance. All groups in which NaOCl was ultrasonically activated had significantly lower CFU values than the syringe-and-needle irrigation and control groups (p<.05). Ultrasonic activation with the stainless-steel file and blue heat-treated Ni-Ti file significantly reduced the biofilm volume compared with other groups (p<.05). Overall, UAI with the blue heat-treated file resulted in the highest antibacterial and biofilm removal efficacy. UAI with different inserts had differential antibiofilm effects. The blue heat-treated Ni-Ti ultrasonic insert resulted in the greatest antibacterial and biofilm removal from dentine in this standardized root canal model.

Efficacy of different irrigation technique in simulated curved root canals.

The aim of this study was to assess the influence of the canal curvature on the efficacy of sonically, ultrasonically, and laser-activated irrigation in removing a biofilm-mimicking hydrogel (BMH) from simulated canal irregularities. Transparent resin blocks containing a curved root canal (40° or 60°) were used as test models. A 4-mm groove at 1 mm from the apex was filled with BMH. Five different irrigation procedures were performed (n=20): needle irrigation (NI), EndoActivator (EA), Eddy, ultrasonically activated irrigation (UAI) (Irrisafe), and laser-activated irrigation (LAI) using a pulsed erbium laser (PIPS approach). All protocols were executed for 3×20s. Images of the groove were taken before and after irrigation, and the percentage BMH removal was calculated using image analysis software. In the 40° canal curvature model, the highest BMH removal was observed for UAI (99.9%), yielding a significantly better removal than that of EA (57.2%) and NI (53.8%), but not of LAI (96.8%) and Eddy (99.4%). In the 60° canal curvature model, UAI removed 99.5%, which resulted in significantly greater hydrogel removal than all other groups (P < 0.05). The difference between LAI (82.5%) and Eddy (78.1%) was not statistically significant, but both were more effective than EA (13.5%) and NI (7.3%). Canal curvature negatively affects the cleaning efficacy of different irrigation methods. The effect was most pronounced for the sonic techniques, while this was not the case for UAI. This could be ascribed to the prebent ultrasonic tip. Despite the position of the laser tip at the orifice level, fluid streaming during LAI resulted in substantial BMH removal beyond the curve.

The comparison of cleaning efficacy and apical extrusion of advanced irrigation activation methods with a novel Er:YAG laser modality: sweeps

Laser-activated irrigation (LAI) is an activation method that is based on transferring pulsed energy to the irrigation solution by using different fiber tips and generating explosive vapor bubbles with a secondary cavitation effect, causing rapid solution movement through the root canal. This study aimed to compare different types of LAI and ultrasonically activated irrigation (UAI) in terms of cleaning efficacy by using scanning electron microscopy (SEM) images. Sixty straight and single-rooted mature mandibular premolars were prepared with ProTaper Ni-Ti rotary instruments up to F4. According to the final irrigation/agitation protocols, four experimental groups (n = 15) were generated as conventional laser–activated irrigation (group 1: C.LAI), photon-induced photoacoustic streaming (group 2: PIPS), shock wave–enhanced emission photoacoustic streaming (group 3: SWEEPS), and passive ultrasonic irrigation (group 4:UAI). The irrigation protocols were performed for 60 s with 2.5% NaOCl and 17% EDTA. Debridement was evaluated using SEM with a scoring system. Apical extrusion was calculated using cube-shaped flower arrangement foam by subtracting the initial weights from the final weights. All data were statistically analyzed. C.LAI and SWEEPS showed significantly lower debris scores than PIPS and UAI (p < 0.001). However, there was no significant difference between C.LAI and SWEEPS. In the PIPS group, significantly more debris residue was found compared with the other groups. Apical extrusion was significantly lower in the PUI groups than in the laser-activated groups (C.LAI, PIPS, SWEEPS). There was no significant difference between laser-activated groups. It can be concluded that the use of the C. LAI and novel laser-activated irrigation modality (SWEEPS) provides greater cleaning efficacy compared to UAI and PIPS. Besides, the observed results should not be generalized to teeth with shorter or longer root length and smaller or larger canal preparation with immature root development and open apices. In teeth with resorption, perforation defects or immature roots with open apex, the higher amount of apical extrusion should also be taken into account.

Comparison of Needle, Ultrasonic, and Laser Irrigation for the Removal of Calcium Hydroxide from Mandibular Molar Root Canals

Objective: This study aimed to compare the efficacy of conventional needle irrigation (CI), ultrasonically activated irrigation (UAI), photon-induced photoacoustic streaming (PIPS), and shock wave-enhanced emission photoacoustic streaming (SWEEPS) in removing calcium hydroxide [Ca(OH)2] from root canals of mandibular molars using microcomputed tomography. Background: Various adjunctive irrigation strategies have been recommended to improve the removal of Ca(OH)2. No reports have evaluated the SWEEPS laser-activated method for the removal of Ca(OH)2 from root canals of mandibular molars. Materials and methods: Forty mandibular molars were instrumented and filled with Ca(OH)2. Four irrigation groups (CI, UAI, PIPS, and SWEEPS) were established. The volume of root canals and Ca(OH)2 and the Ca(OH)2 volume reduction percentage (%Rd) were calculated. Data were analyzed by one-way analysis of variance and Kruskal-Wallis analysis of variance. Results: The residual Ca(OH)2 in the apical third was higher than that in the cervical and middle thirds in all groups (p < 0.05). Comparison of the %Rd of Ca(OH)2 in mesial canals revealed that PIPS and SWEEPS removed more Ca(OH)2 than CI and UAI in the cervical third (p < 0.05). The middle third of the mesial canals and the cervical and middle thirds of the distal canals did not show significant differences among groups (p > 0.05). Significant differences in the %Rd of Ca(OH)2 were noted between CI and other groups in the apical third of mesial and distal canals (p < 0.05). No group demonstrated complete removal of Ca(OH)2. Conclusions: UAI and laser-activated irrigation significantly improved Ca(OH)2 removal in the apical third of mesial and distal canals. No agitation technique could completely remove Ca(OH)2.

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.