title: Postoperative pain after the application of two different irrigation devices in a prospective randomized clinical trial. Effect of apical preparation size and preparation taper on irrigant volume delivered by using negative pressure irrigation system. Comparison of the effectiveness of three irrigation techniques in reducing intracanal Enterococcus faecalis populations: an in vitro study. Statistics notes: Absence of evidence is not evidence of absence Preparation of oval-shaped root canals in mandibular molars using nickel-titanium rotary instruments: a micro-computed tomography study. Microbiological evaluation of different irrigation protocols on root canal disinfection in teeth with apical periodontitis: an in vivo study. Tissue response to root canal irrigation systems in dogs’ teeth with apical periodontitis Comparative evaluation of canal isthmus debridement efficacy of modified EndoVac technique with different irrigation systems. A bio-molecular film ex-vivo model to evaluate the influence of canal dimensions and irrigation variables on the efficacy of irrigation. In Vivo Intracanal Temperature Evolution during Endodontic Treatment after the Injection of Room Temperature or Preheated Sodium Hypochlorite. In vivo efficacy of three different endodontic irrigation systems for irrigant delivery to working length of mesial canals of mandibular molars. In vitro comparisons of debris removal of the EndoActivator system, the F file, ultrasonic irrigation, and NaOCl irrigation alone after hand-rotary instrumentation in human mandibular molars. Ex vivo antimicrobial efficacy of the EndoVac system plus photodynamic therapy associated with calcium hydroxide against intracanal Enterococcus faecalis. Pulp Revascularization of Immature Dog Teeth with Apical Periodontitis Using Triantibiotic Paste and Platelet-rich Plasma: A Radiographic Study. Comparison of irrigant penetration up to working length and into simulated lateral canals using various irrigating techniques. Antimicrobial efficacy of two irrigation techniques in tapered and nontapered canal preparations: an in vitro study.
abstract: INTRODUCTION The extrusion of irrigation solutions beyond the apical constriction may result in postoperative pain .  Sodium hypochlorite can cause severe tissue irritation and necrosis outside the root canal system if extruded into the periodontal ligament ( PDL ) space . Different delivery techniques were discussed to reduce this potential risk . The aim of this study was to compare the postoperative level of pain after root canal therapy using either endodontic needle irrigation or a negative apical pressure device . MATERIAL AND METHODS In a prospect i ve r and omized clinical trial , 110 asymptomatic single-rooted anterior and premolar teeth were treated endodontically with two different irrigation techniques . The teeth were r and omly assigned to two groups . In the MP group ( n = 55 ) , procedures were performed using an endodontic irrigating syringe ( Max-i-Probe ; Dentsply Rinn , Elgin , IL ) . The EV group ( n = 55 ) used an irrigation device based on negative apical pressure ( EndoVac ; Discus Dental , Culver City , CA ) . Postoperatively , the patients were prescribed ibuprofen 200 mg to take every 8 hours if required . Pain levels were assessed by an analog scale question naire after 4 , 24 , and 48 hours . The amount of ibuprofen taken was recorded at the same time intervals . RESULTS During the 0- to 4- , 4- to 24- , and 24- to 48-hour intervals after treatment , the pain experience with the negative apical pressure device was significantly lower than when using the needle irrigation ( p < 0.0001 [ 4 , 24 , 48 hours ] ) . Between 0 and 4 and 4 and 24 hours , the intake of analgesics was significantly lower in the group treated by the negative apical pressure device ( p < 0.0001 [ 0 - 4 hours ] , p = 0.001 [ 4 - 24 hours ] ) . The difference for the 24- to 48-hour period was not statistically different ( p = 0.08 ) . The Pearson correlation coefficient revealed a strongly positive and significant relationship for the MP group ( r = 0.851 , p < 0.001 ) and the EV group ( r = 0.596 , p < 0.0001 ) between pain intensity and the amount of analgesics . CONCLUSION The outcome of this investigation indicates that the use of a negative apical pressure irrigation device can result in a significant reduction of postoperative pain levels in comparison to conventional needle irrigation INTRODUCTION The purpose of this investigation was to determine the effect that apical preparation size and preparation taper had on the volume of irrigant delivered to the working length of a root canal preparation in a clinical ly relevant amount of time . METHODS Forty intact human single-rooted teeth were r and omly distributed into 2 separate phases . The first phase aim ed to determine the smaller apical size that will allow more volume of irrigant at working length . All sample s had the same taper and were sequentially instrumented to sizes of 30.06 , 35.06 , 40.06 , and 45.06 . The second phase aim ed to determine the taper that will allow more volume of irrigant at working length . Teeth were sequentially instrumented to 40.02 , 40.04 , 40.06 , and 40.08 . All sample s were irrigated by using the micro-cannula , and the volume of sodium hypochlorite suctioned at working length under negative pressure was measured during a period of 30 seconds by using a custom recovery device . RESULTS An increase in size from ISO # 35 to ISO # 40 result ed in a percentage gain of approximately 44 % in mean irrigant volume , whereas an increase in size from ISO # 40 to ISO # 45 result ed in a percentage gain of approximately 4 % . An increase in taper from 0.02 through 0.08 result ed in percentage gains of approximately 74 % , 5.4 % , and 2.4 % increase , respectively . CONCLUSIONS The data demonstrated that an increase in apical preparation size and taper result ed in a statistically significant increase in the volume of irrigant . In addition , an apical enlargement to ISO # 40 with a 0.04 taper will allow for tooth structure preservation and maximum volume of irrigation at the apical third when using the apical negative pressure irrigation system INTRODUCTION Several irrigation techniques have been recently introduced with the main objective of improving root canal disinfection . This in vitro study aim ed at comparing the intracanal bacterial reduction promoted by chemomechanical preparation with 3 different irrigation techniques . METHODS Root canals from extracted teeth were contaminated with Enterococcus faecalis ATCC 29212 for 7 days and then r and omly distributed into 3 experimental groups of 20 teeth each : group 1 , conventional irrigation with NaviTip needles inserted up to 3 mm short of the working length ; group 2 , same as group 1 , but supplemented with final irrigant activation by the EndoActivator system ; and group 3 , irrigation with the EndoVac system . NaOCl and ethylenediaminetetraacetic acid ( EDTA ) were the irrigants used in all experimental groups . The overall preparation time was kept constant for the groups , but the total volume ranged from 20 mL ( groups 1 and 2 ) to 43 mL ( group 3 ) . The control group was irrigated with saline solution ( total volume , 43 mL ) . Sample s taken before and after chemomechanical procedures were cultured , and the colony-forming units ( CFUs ) were counted . RESULTS Reduction in the bacterial population s was highly significant for all groups . The 3 experimental groups with NaOCl and EDTA as irrigants were significantly more effective than the control group with saline in reducing CFU counts . There were no significant differences between the 3 techniques tested . CONCLUSIONS There was no evident antibacterial superiority of any of the irrigation techniques evaluated in the present in vitro model R and omized controlled clinical trials are conducted to determine whether differences of clinical importance exist between selected treatment regimens . When statistical analysis of the study data finds a P value greater than 5 % , it is convention to deem the assessed difference nonsignificant . Just because convention dictates that such study findings be termed nonsignificant , or negative , however , it does not necessarily follow that the study found nothing of clinical importance . Subject sample s used in controlled trials tend to be too small . The studies therefore lack the necessary power to detect real , and clinical ly worthwhile , differences in treatment . Freiman et al. found that only 30 % of a sample of 71 trials published in the New Engl and Journal of Medicine in 1978 - 79 with a P value greater than 10 % were large enough to have a 90 % chance of detecting even a 50 % difference in the effectiveness of the treatments being compared , and they found no improvement in a similar sample of trials published in 1988 . It is therefore wrong and unwise to interpret so many negative trials as providing evidence of the ineffectiveness of new treatments . One must instead seriously question whether the absence of evidence is a valid justification for inaction . Efforts must be made to look for quantification of an association rather than just a P value , especially when the risks under investigation are small . The authors cite a recent trial comparing octreotide and sclerotherapy in patients with variceal bleeding  , as well as the overview of clinical trials evaluating fibrinolytic treatment for preventing reinfa rct ion after acute myocardial infa rct ion as examples INTRODUCTION This study evaluated the prepared surface areas of oval-shaped canals in distal roots of m and ibular molars using four different instrumentation techniques . METHODS Teeth were prescanned and reconstructed using micro-computed tomography ( MCT ) scans at low resolution ( 68 microm ) . Forty-eight molars with ribbon-shaped/oval distal root canals were selected and r and omly assigned to four groups . Distal canals ( n = 12 each ) were prepared by circumferential filing using Hedström files to apical size # 40 ( group H/CF ) ; with ProTaper nickel-titanium rotaries to finishing file 4 ( F4 ) considering the distal canal as 1 canal ( group PT/1 ) ; ProTaper to F4 considering buccal and oral aspects of the distal canal as 2 individual canals ( group PT/2 ) ; ProTaper to F4 in a circumferential filing motion ( PT/CF ) . Before and after shaping , teeth were evaluated using MCT at 34-microm resolution . The percentage of prepared surface was assessed for the full canal length and the apical 4 mm . Statistical analysis was performed using analysis of variance and Bonferroni/Dunn multiple comparisons . RESULTS Preoperatively , canal anatomy was statistically similar among the groups ( p = 0.56 ) . Mean ( + /- st and ard deviation ) untreated areas ranged from 59.6 % ( + /-14.9 , group PT/2 ) to 79.9 % ( + /-10.3 , PT/1 ) for the total canal length and 65.2 % to 74.7 % for the apical canal portion , respectively . Canals in group PT/1 had greater untreated surface areas ( p < 0.01 ) than groups PT/2 and PT/CF . Among all groups , amounts of treated surface areas were statistically similar in the apical 4 mm . CONCLUSIONS Preparations of oval-shaped root canals in m and ibular molars left a variable portion of surface area unprepared regardless of the instrumentation technique used . However , considering oval canals as two separate entities during preparation appeared to be beneficial in increasing overall prepared surface The present in vivo study was design ed to evaluate the efficacy of apical negative pressure irrigation ( ANP ) , passive ultrasonic irrigation ( PUI ) and positive pressure irrigation ( PP ) in the reduction of intracanal bacteria of dogs ' teeth with pulp necrosis and apical periodontitis . Eighty root canals were r and omly distributed into 3 experimental and 2 control groups according to the irrigation delivery system : group ANP ( n=20 ) , group PUI ( n=20 ) , group PP ( n=20 ) , group PC ( positive control - sterile saline irrigation ; n=10 ) and group NC ( negative control - vital pulps not subjected to bacterial inoculation ; n=10 ) . The first sample ( S1 ) was collected at baseline , and the second sample ( S2 ) was collected after the disinfection protocol s. All sample s were seeded in culture media for anaerobic bacteria . CFU counts were analyzed statistically by the Kruskal-Wallis , Dwass-Steel-Critchlow-Fligner post-hoc and Chi-square followed by Tukey like multiple comparisons for proportions ( α=0.05 ) . All experimental groups were effective in reducing Gram-positive bacteria compared with PC ( p<0.05 ) . Regarding the reduction of Gram-negative bacteria , group ANP was significantly better than PP ( p<0.05 ) . No statistically significant difference could be found between PP and PUI ( p>0.05 ) . In dog 's teeth with apical periodontitis , the use of ANP and PUI can be considered promising disinfection protocol s as both delivery systems promoted a significant bacterial reduction Objectives The aim of this study was to compare the efficacy of apical negative pressure irrigation ( ANP ) and passive ultrasonic irrigation ( PUI ) with apical positive pressure irrigation ( PP — conventional irrigation ) in the periapical repair of dogs ’ teeth with apical periodontitis . Methods Forty-nine mesial and distal root canals of premolars of three dogs with experimentally induced periapical lesions were subjected to a single-session root canal treatment . The teeth were r and omly assigned to three groups : ANP , PUI , and PP ( control ) . After 180 days , the animals were euthanized , and the anatomic pieces were removed and subjected to histotechnical processing for morphological and morphometric histological analyses of hematoxylin and eosin (HE)-stained sections under conventional and fluorescence microscopy . Periapical lesion size before and 180 days after root canal treatment was measured by periapical radiographic examination . Tartrate-resistant acid phosphatase ( TRAP ) histoenzymology was performed for osteoclast counting and Brown and Brenn staining to assess bacteria . Data were analyzed statistically by the Kruskal-Wallis test ( α = 5 % ) . Result There were no statistically significant differences among the groups regarding periapical lesion size in the radiographic evaluation ( p = 0.91 ) . In the comparison of histopathological parameters , group ANP presented more homogeneous results . There was a statistically significant difference ( p = 0.02 ) between groups ANP and PP , with better results for group ANP in which milder infiltrate inflammatory was observed . No statistically significant difference ( p > 0.05 ) was found among the groups with respect to periodontal ligament space , presence of mineralized tissue resorption , size of the periapical lesions , and number of osteoclasts . Conclusion Although the three irrigation systems elicited similar periapical tissue response with respect to almost all evaluated parameters , ANP presented the mildest inflammatory infiltrate , suggesting an advantage over PP in the indication for clinical use . Clinical relevance Irrigation of the root canal systems is an extremely important step in root canal treatment . Therefore , it is of relevance to evaluate the efficacy of these systems by in vivo experimental models to provide scientific background for the clinical practice INTRODUCTION The purpose of this study was to evaluate the canal isthmus debridement efficacy of a new modified EndoVac ( Discus Dental , Culver City , CA ) irrigation protocol in comparison with EndoVac , passive ultrasonic irrigation ( PUI ) , and conventional needle irrigation in mesial roots of m and ibular molars . METHODS The mesial roots of 64 extracted m and ibular molars mounted in resin using Kuttler 's endodontic cube , sectioned at 2 and 4 mm from the working length , were r and omly divided into 4 groups ( n = 16 ) : group 1 : Max-I-Probe ( Dentsply Tulsa Dental , York , PA ) , group 2 : EndoVac ( EVI ) , group 3 : modified EndoVac , and group 4 : PUI . The specimens were reassembled and instrumented . A st and ard irrigation protocol was used during cleaning and shaping and final irrigation with the 4 irrigation/agitation techniques . Images of the isthmus region were taken before and after cleaning and shaping and after final irrigation . The percentage reduction of debris in the isthmus region was calculated by using the software program Image J ( v1.43 ; National Institutes of Health , Bethesda , MD ) . Intergroup analysis was performed using the Kruskal Wallis and Mann-Whitney U tests . Intragroup analysis was performed using Friedman and Wilcoxon signed rank tests . The level of significance was set at P < .05 . RESULTS Intragroup analysis revealed a statistically significant difference in the percentage reduction of debris after cleaning and shaping and after final irrigation protocol in all the groups ( P < .001 ) . The final irrigation protocol produced significantly cleaner canal isthmuses in all the groups ( P < .001 ) . On intergroup analysis , the modified EVI group performed significantly better than the other groups . The EVI and PUI groups performed better than the Max-I-Probe group . There was no statistical significance between the EVI and PUI groups . CONCLUSIONS Canal isthmuses were significantly cleaner with the modified EndoVac irrigation technique when compared with the cleanliness seen with the other irrigation systems AIMS To devise an ex vivo model to test the efficacy of irrigation ( static/dynamic ) in removing a bio-molecular film from root canal walls . METHODOLOGY Forty human teeth with single straight canals were r and omly allocated to two groups for static ( n = 20 ) or dynamic ( n = 20 ) irrigation . The root canals were prepared to different apical sizes ( 20 , 40 ) and tapers ( 0.04 , 0.08 ) . The teeth were split longitudinally into two , stained collagen was applied to the canal surfaces and the tooth reassembled in a silicone matrix for dynamic or static irrigation . Digital images of the canal surface were taken before and after irrigation with 9 , 18 , 27 and 36 mL solution . The percentage of canal surface covered with stained collagen was quantified ( ipWin4 ) . The data were analysed using paired t-tests and linear regression models . RESULTS All the five explanatory variables : ' volume of irrigant used ' , ' mode of irrigation ' , ' orientation of open port of needle ' , ' corono-apical level of canal ' and ' root canal dimension ' had a significant ( P < 0.001 ) influence on outcome of irrigation . The corono-apical level of canal was the most dominating factor . After irrigation , the apical third had 19.9 % and 33.8 % less area covered with the bio-molecular film than the middle and coronal thirds respectively . CONCLUSIONS The stained collagen bio-molecular film could not be removed completely by either static or dynamic irrigation . Factors influencing removal , in rank order of decreasing priority , were : corono-apical level , apical size and taper of canal preparation , and dynamic/static irrigation INTRODUCTION Heating a sodium hypochlorite solution improves its effectiveness . The aim of this study was to measure the in vivo temperature changes of sodium hypochlorite solutions that were initially preheated to 66 ° C or at room temperature inside root canals during routine irrigation . METHODS Thirty-five root canals were prepared to ISO size 40 with 4 % taper . A type K ( nickel-chromium-nickel ) thermocouple microprobe ( Testo NV , Ternat , Belgium ) was positioned within 3 mm of the working length to measure the temperature at 1-second intervals . In each canal , 2 test protocol s were evaluated in a r and omized order with 3 % sodium hypochlorite solutions : ( 1 ) preheated to 66 ° C and ( 2 ) at room temperature . The temperature measurements began 5 seconds before the 25 seconds of irrigant injections and continued for 240 seconds . This result ed in 270 data points for each protocol . RESULTS The temperature of the irrigant at room temperature increased from the initial intracanal temperature after injection of 20.7 ° C ( ±1.2 ° C ) to 30.9 ° C ( ±1.3 ° C ) in 10 seconds and to 35 ° C ( ±0.9 ° C ) after 240 seconds . The temperature of the preheated to 66 ° C solution decreased from 56.4 ° C ( ±2.7 ° C ) to 45.4 ° C ( ±3.0 ° C ) after 5 seconds , reached 37 ° C ( ±0.9 ° C ) after 60 seconds , and reached 35.7 ° C ( ±0.8 ° C ) after 240 seconds . CONCLUSIONS The original temperatures of the sodium hypochlorite solutions were buffered inside the root canal and tended to rapidly evolve to equilibrium . The findings of this study contribute to an improved underst and ing of the thermodynamic behaviors of irrigant solutions inside root canals in vivo INTRODUCTION Many in vitro studies have debated over the ability of different irrigant delivery and /or agitation systems to reach the apical third of curved root canals ; however , little is known about irrigant penetration in vivo . Therefore , the purpose of this study was to compare the efficacy of the conventional endodontic irrigation needle , passive ultrasonic irrigation ( PUI ) , and a negative pressure system for irrigant delivery to working length ( WL ) of mesial canals of m and ibular molars . METHODS Thirty mesial canals of 30 vital m and ibular first or second molars were r and omly assigned into 3 groups ( n = 10 ) : ( 1 ) Monoject syringe with 27-gauge needle ; ( 2 ) PUI with IrriSafe tip ; and ( 3 ) EndoVac system . All canals were treated following the same preparation protocol to size 35/0.04 by using 5.25 % NaOCl as irrigant during preparation procedure . Before obturation , canals were irrigated with 1 mL of a radiopaque solution by using the assigned irrigation system , and a digital radiograph was taken by using a parallel technique . With the aid of image editing software the distance between WL and maximum irrigant penetration was measured . RESULTS Mean distances for Monoject , PUI , and EndoVac groups were 1.51 mm , 0.21 mm , and 0.42 mm , respectively . Analysis of variance test showed statistically significant differences between groups ( P < .001 ) . Tukey honestly significant difference test showed statistically significant differences between the Monoject group and the other 2 groups ( P < .001 ) but no significant differences between PUI and EndoVac groups ( P = .06 ) . CONCLUSIONS PUI and EndoVac are more effective than the conventional endodontic needle in delivering irrigant to WL of root canals INTRODUCTION The purpose of this in vitro study was to compare the debris removal efficacy of the EndoActivator system , the F file , ultrasonic irrigation , or 6 % NaOCl irrigation alone in human m and ibular molars after h and -rotary instrumentation . METHODS A custom brass cube ( K-Kube ) was used to create a sealed canal system , allowing each tooth to serve as its own control . Forty extracted m and ibular molars were r and omly divided into 4 equal experimental groups . Each tooth was mounted , sectioned at 1 , 3 , and 5 mm from the working length , and then reassembled into the K-Kube , and the mesial roots were similarly prepared by using h and -rotary instrumentation . For final debridement , group 1 used F file for 30 seconds , group 2 used EndoActivator system for 30 seconds , group 3 used ultrasonic irrigation for 30 seconds , and group 4 used irrigation with 6 % NaOCl within 1 mm of working length . All groups received a final irrigation with 6 % NaOCl in each canal . Specimens were evaluated at 1 , 3 , and 5 mm from the working length for cleanliness by capturing a digital image with a stereomicroscope . All specimens had the percent cleanliness for each canal and isthmus calculated both before and after final debridement . Statistical analysis was completed by using a repeated- measures analysis of variance with Tukey post hoc tests . RESULTS AND CONCLUSIONS The results showed no statistically significant difference in canal or isthmus cleanliness among the 4 groups , but there was a statistically significant difference ( P < .001 ) in canal cleanliness between the 1-mm level versus the 3-mm and 5-mm levels for all of the groups AIM To evaluate the ex vivo efficacy of the EndoVac system and photodynamic treatment ( PDT ) as adjuncts to chemomechanical debridement associated with calcium hydroxide ( CaOH2 ) in reducing the levels of intracanal Enterococcus faecalis . METHODOLOGY One hundred and twenty-five sterile premolar teeth were conventionally accessed , prepared and then contaminated with E. faecalis ( ATCC 29212 ) for 30 days . Teeth were r and omly divided into 4 groups : Control ( chemomechanical debridement with conventional irrigation ) ; Endovac ( chemomechanical debridement with EndoVac system ) ; PDT ( chemomechanical debridement with conventional irrigation and PDT ) and Endovac+PDT ( chemomechanical debridement with EndoVac and PDT ) . The irrigants used in all groups were 5.25 % sodium hypochlorite and 17 % EDTA . After treatment , an intracanal dressing ( CaOH2 ) was applied in all canals for 7 days . Sample s were obtained before ( T1 ) and after the therapeutic procedures ( T2 ) and , after intracanal medication ( T3 ) , plated onto BHI media and incubated ( 37 ° C , 48 h ) to determine the colony-forming units ( CFU mL(-1 ) ) . RESULTS The overall mean cell counts ( CFU mL(-1 ) ) of E. faecalis were high at the initial contamination ( T1 ) . A significant reduction ( P < 0.05 ) of E. faecalis mean counts was observed in all groups from baseline ( T1 ) to both post-therapy samplings ( T2 and T3 ) ; no differences amongst the groups were detected . No significant change in bacterial counts from T2 to T3 was detected . CONCLUSION The adjunctive use of the EndoVac system and the photodynamic treatment , in combination or not , was as effective as the conventional chemomechanical debridement associated with CaOH2 on reducing the counts of intracanal E. faecalis INTRODUCTION This study evaluates radiographically the efficacy of 4 revascularization protocol s in necrotic-infected immature dog teeth with apical periodontitis ( AP ) . METHODS Forty double-rooted immature premolar teeth from 4 female beagle dogs aged 5 months were used . Four teeth were left untouched as negative controls ; the other 36 teeth were infected to develop pulp necrosis and AP following different treatment protocol s. Four teeth were left untreated and assigned to the positive control group , and the last 28 teeth were r and omly assigned into 4 experimental groups of 8 teeth : A1 , sodium hypochlorite ( NaOCl ) + a blood clot ; A2 , NaOCl + platelet-rich plasma ( PRP ) ; B1 , NaOCl + modified triantibiotic paste ( mTAP ) + a blood clot ; and B2 , NaOCl + mTAP + PRP . Teeth were monitored radiographically for 6 months regarding healing of periapical radiolucencies , thickening of the dentinal walls , and apical closure of roots . RESULTS Significant differences ( P < .05 ) between the 4 groups were evident in the percentage of teeth showing improvement of periapical radiolucencies ( 62.5 % ) , continued radiographic thickening of radicular walls ( 53.1 % ) , radiographic apical closure ( 43.8 % ) , and deposition of hard tissue on radicular dentin walls ( 53.1 % ) . Group B2 showed maximal improvement in the 3 variables assessed ( P < .05 ) . Group A1 showed the minimum percentages in the 3 parameters assessed ( P < .05 ) . CONCLUSIONS These results suggest that an intracanal dressing of mTAP and the use of PRP as scaffold improves the success rate of the revascularization procedure AIM To evaluate the effect of an apical negative pressure system , a passive ultrasonic irrigation system and a combination of both apical negative pressure and passive ultrasonic irrigation on the penetration of the  irrigating contrast solution ( ICS ) up to working length and into simulated lateral canals . METHODOLOGY The root canals of 64 single-rooted teeth were instrumented using the ProTaper rotary system . In each sample , three simulated lateral canals were created at 2 , 4 and 6 mm levels from the root apex using a 06-size C+ file ( Dentsply Maillefer , Ballaigues , Switzerl and ) . Sample s were r and omly assigned into 4 experimental groups ( n = 16 ) : group I - conventional needle irrigation , group II - passive ultrasonic irrigation , group III - apical negative irrigation system and group IV - combination of passive ultrasonic irrigation and apical negative pressure irrigation system . To examine irrigating solution penetration , Indian ink was mixed with 5.25 % NaOCl and delivered into the root canals . Sample s were then assessed by direct observation of the images taken using Canon EOS rebel T3 . The depth of penetration of ICS up to the working length and into the simulated lateral canals was analysed using chi-squared tests . RESULTS The combination ( ANP and PUI ) and ANP group had significantly deeper ICS penetration up to the working length ( P < 0.001 ) . The combination ( ANP and PUI ) and the PUI group exhibited significantly greater ICS penetration into lateral canals at the 6 mm level ( P < 0.001 ) . At the 4 and 2 mm levels , the combination of ANP and PUI had significantly greater ICS penetration into the lateral canals than the other groups ( P < 0.001 ) . CONCLUSIONS The combination of ANP and PUI was the only group able to achieve irrigating contrast solution penetration both up to the working length and into lateral canals The aim of this in vitro study was to determine whether irrigation with apical negative pressure was more effective than traditional positive-pressure irrigation in eradicating Enterococcus faecalis from preshaped root canals . Fifty-four extracted m and ibular molars were instrumented to produce either a non-tapered or tapered preparation , sterilized , inoculated with E. faecalis for 30 days , and then r and omly assigned into the following groups : group 1 - -non-tapered preparation and negative-pressure irrigation , group 2 - -non-tapered preparation and positive-pressure irrigation , group 3 - -tapered preparation and positive-pressure irrigation , and group 4 - -tapered preparation and negative-pressure irrigation .  Mesial canals were sample d before and after final irrigation and sample s incubated aerobically for 48 hours at 37 degrees C. Scanning electron microscopic analysis confirmed dense bacterial colonies in the positive control , consistent with biofilm formation . A statistically significant difference was evident when comparing apical negative-pressure irrigation to positive-pressure irrigation ( p=0.004 ) . There was no statistically significant difference in colony-forming units ( CFUs ) between sizes # 35 and # 45 , nor between tapered and non-tapered preparation . The results of this in vitro study showed that apical negative-pressure irrigation has the potential to achieve better microbial control than traditional irrigation delivery systems
target: Inconclusive results were reported about the cleaning and disinfection accomplished by the two irrigation methods .
  There is insufficient evidence to cl aim general superiority of any one of these methods .
background: The aim of this study was to systematic ally review and critically analyse the published data on the treatment outcome ( primary outcome ) and on the  cleaning and disinfection of root canals  ( secondary outcomes ) achieved by negative pressure irrigation as compared to syringe irrigation .