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Background: To determine the amount of apical extrusion between various file systems during the retreatment procedure and to determine the effect of taper on the same. Materials and Method: Seventy mandibular extracted premolars were taken, and preparation was performed using a Woodpecker file (Woodpecker Medical Instrument Co., Ltd., Guilin, China) (25/0.06). The gutta‑percha (GP) was removed from each specimen with H file (#40/0.02) to simulate retreatment in seven groups (n = 10) using ProTaper Next (PTN;Dentsply, Maillefer, Ballaigues, Switzerland) (PTN) (30/0.07), Reciproc (25/0.08), Hyflex CM (30/0.06), Mtwo (30/0.05), Neoendo flex (30/0.04), Neoendo hybrid (30/0.04), and Flexicon file (30/0.06). The specimens were held with the help of a rubber stopper and put in the Eppendorf tube of volume 4 mL (pre‑weighed before retreatment). The debris that was on the root surface of the specimen was washed with distilled water with 1 mL volume, kept in the oven, and then again weighed after 7 days. Results: Apical extrusion was found in the following order: HYFLEX CM (LEAST) < FLEXICON < PROTAPER NEXT < RECIPROC < NEOENDO FLEX < NEOENDO HYBRID < MTWO (HIGHEST). Conclusion: W Hyflex CM and Flexicon files showed lesser extrusion of debris than others. [ABSTRACT FROM AUTHOR]

Aim: The aim of the study is to evaluate and compare the quantity of apical debris extrusion from the root canals during biomechanical preparation by various rotary (reciprocating, Protaper Next [PTN] continuous) and manual hand filing system and by means of Crown-Down and Step Back techniques. Materials and Methods: Eighty mature, human mandibular premolars with single canals were randomly divided into four groups of twenty teeth each. Each group was instrumented using one of the four instrumentation systems: Group A: WaveOne, Group B: PTN, Group C: Hand file with Crown Down, Group D: Hand file with Step Back. Extruded debris was collected in preweighed Eppendorf tubes and the extruded irrigant was evaporated. The weight of the dry extruded debris was established by comparing the pre and post-instrumentation weight of Eppendorf tubes for each group. Results: Mean comparison of groups in different instrumentation by ANOVA presented that hand file with Step-Back technique is showed maximum amount of apical extrusion debris and continuous rotary file system showed the minimum amount of extrusion debris (P < 0.001). Conclusions: The current ex vivo study demonstrated reciprocating single file WaveOne and continuous rotary multiple file system lead to significantly less debris extrusion than manual hand file techniques. Reciprocating single file WaveOne extruded more debris than continuous rotary PTN multiple file system. More amount of debris was extruded in the group with Step-Back hand filing than Crown-Down technique. [ABSTRACT FROM AUTHOR]

Background: Prevention of the debris from extruding to the periapical region is an important aspect to be taken care of as its extrusion can result in pain, periapical inflammation, and delayed healing owing to the presence of highly infective components in the debris. Aim: The present trial was aimed to compare and assess the amount of debris extruded apically using the single-file reciprocating system - WaveOne GOLD and single file rotary system - OneShape in root canal preparations in vitro. Materials and Methods: Thirty mandibular premolars were divided into two groups (15 samples each) prepared with a single-file reciprocating system - WaveOne GOLD and single-file rotary system - OneShape. Debris extruded was collected and then stored in an incubator. The final weight was calculated after obtaining the mean of three consecutive weights obtained for each tooth. The data were compared using the ANOVA and Turkey's post hoc analysis. Results: Debris extrusions were recorded in both groups and analysis revealed statistical differences in weight before and after the instrumentation procedures in both groups. When compared, reciprocating single file – WaveOne GOLD extruded more debris than rotary single file system – OneShape with a P < 0.001. Conclusions: The rotary instrumentation systems extrude lesser debris apically than the reciprocating instrumentation system. The difference found was statistically significant. [ABSTRACT FROM AUTHOR]

Background: The success of endodontic treatment depends on the chemomechanical preparation of the tooth. However, the debris produced during canal preparation may extrude through the apical foramen causing postoperative complications. Aim: The aim of this study is to compare the apical debris extrusion during root canal preparation in primary anterior teeth using hand files, rotary ProTaper files, and rotary Kedo-S files. Materials and Methods: Forty-five freshly extracted primary canine with mature apices and a single canal were randomly divided into three groups for instrumentation as follows (n = 15): Group 1: hand files; Group 2: rotary ProTaper files; and Group 3: rotary Kedo-S files. Myers and Montgomery experimental model was used for this study. Apically extruded debris collected in a preweighed Eppendorf tubes was placed in the incubator at 70°C for 5 days. The weight of the debris collected was determined by subtracting the pre- and post-instrumentation weight of the Eppendorf tubes. The data collected were analyzed using the analysis of variance and Tukey's post-hoc tests. Results: Hand files produced more apical debris extrusion than ProTaper and Kedo-S files (P < 0.05) while Kedo-S produced the least (P < 0.05). Conclusion: All instrumentation systems cause apical debris extrusion. Kedo-S produced less apical debris extrusion when compared to the hand files and ProTaper files. [ABSTRACT FROM AUTHOR]

Background: Endodontic instrumentation is liable to cause some postinstrumentation pain (PIP). Rotary endodontic instruments differ in their design, metallurgy, surface treatment, etc. Aim: This randomized clinical trial aimed to assess the incidence of PIP after root canal instrumentation with three different rotary endodontic systems which differ in their design, namely, ProTaper, Mtwo, and K3. Materials and Methods: A total of 150 patients between the ages of 25 and 50 were chosen for the study. Teeth with asymptomatic irreversible pulpitis due to carious exposure were selected. The patients received local anesthesia by inferior alveolar nerve block. After preparing the access cavity, root canal instrumentation was done with one of the three instruments (n = 50) and closed dressing was given. PIP was assessed every 12 h for 5 days, and tenderness to percussion was analyzed at the end of 1, 3, and 7 days. Statistical Analysis: Mann-Whitney U-test to determine significant differences at P < 0.01. Results: The PIP and tenderness were less in Mtwo group when compared to ProTaper and K3 groups up to 84 h and 72 h respectively and statistically significant (P < 0.05). There was no statistically significant difference between ProTaper and K3 both in PIP and tenderness. Conclusion: Rotary endodontic instrumentation causes some degree of PIP and tenderness to percussion. Among the instruments used, Mtwo causes less PIP and tenderness when compared to ProTaper and K3, and there was no difference between ProTaper and K3. Clinical Relevance: PIP is highly subjective and may vary among different subjects. The apical (3 mm) taper of ProTaper was 0.08 followed by a smaller taper, whereas, the other two files were of a constant 0.06 taper, which means there could have been a greater apical extrusion and therefore more PIP. Despite, the mean of the age was similar, there could have been a difference in the size of the canal and therefore a difference in apical extrusion and PIP. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study is to compare the effects of conventional syringe, passive ultrasonic irrigation (PUI), and EndoIrrigator Plus on the amount of apically extruded debris. Materials and Methods: Thirty extracted human mandibular premolars were selected and randomly assigned to three groups (n = 10). The root canals were irrigated with conventional syringe, PUI, and EndoIrrigator Plus. Sodium hypochlorite was used as an irrigant, and debris was collected in a previously described experimental model (Myers and Montgomery 1991). It was then stored in an incubator at 37°C for 10 days to evaporate the irrigant before weighing the dry debris. The mean weight of debris was assessed, one-way analysis of variance was used for comparison of values, and post hoc Tukey's test was used between groups (P = 0.05). Results: The EndoIrrigator Plus group extruded significantly less debris than PUI and conventional syringe groups (P < 0.05). Furthermore, PUI group extruded significantly less debris than conventional syringe irrigation group (P < 0.05). Conclusions: 1. All the three irrigation systems were associated with apical extrusion of debris, 2. EndoIrrigator Plus system extruded significantly less debris than the PUI system and the conventional syringe irrigation system, 3. PUI system extruded significantly less debris than the conventional syringe irrigation system. [ABSTRACT FROM AUTHOR]

Aim: This study was intended to evaluate the amount of apically extruded debris following root canal preparation with three different instrumentation systems. Materials and Methods: Sixty mandibular incisor teeth were selected and randomly divided into three groups (n = 20/group) according to the instrumentation system used: the ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland), the Twisted File Adaptive (TFA; SybronEndo, Orange, CA, USA), and the WaveOne Gold (WOG; Dentsply Maillefer, Ballaigues, Switzerland). All apically extruded debris was collected and dried in preweighed glass vials. The mean weight of the apically extruded debris was obtained using a microbalance. The time for root canal preparation was also recorded. The data were analyzed using a one-way analysis of variance. Results: The mean weights of apically extruded debris were 0.00035 ± 0.00014 g (PTN); 0.00023 ± 0.0001 g (TFA); and 0.00019 ± 0.0001 g (WOG) (P ˂ 0.01). The mean preparation time value was 301,13 ± 62.14 s (PTN); 234.27 ± 34.88 s (TFA); and 239.8 ± 58.6 s (WOG) (P ˂ 0.05). Conclusions: The PTN system extruded more debris than the TFA and WOG systems. The TFA and WOG systems were faster than the PTN system. [ABSTRACT FROM AUTHOR]

Aims and Objectives: Instrumentation techniques may cause extrusion of microorganisms and their products into the periapical region resulting inflammation and treatment failure. The aim of this ex vivo study was comparing the apical bacterial extrusion in canals prepared with single file versus multiple file rotary systems. Materials and Methods: Ninety-two human single-rooted mandibular first premolars were used. Endodontic access cavities were prepared, and root canals were contaminated with an Enterococcus faecalis (E. faecalis) suspension. The samples were incubated at 37°C for 30 days; the contaminated teeth were divided into four groups of 20 specimens each (1: Reciproc, 2: Mtwo, 3: Neoniti A1, 4: Safesider). Six teeth were not infected and each were prepared with one of the above instruments were considered as negative and six teeth which had been previously infected, were used as positive control groups. Extruded bacteria from the apical foramen during instrumentation were collected into vials containing 0.9% NaCl. The microbial samples were taken from the vials and incubated in brain heart agar medium for 24 h. The resulting bacterial titer, in colony-forming units per mL, was determined. The data entered into SPSS 18 software and were analyzed by Kruskal-Wallis and Mann-Whitney U-tests at 0.05 significance level. Results: Mtwo multifile system showed significantly less bacterial extrusion than Safesider (P = 0.015) and Neoniti A1 (P = 0.042) but did not show significant difference with Reciproc system (P = 0.25). Conclusions: All instrumentation systems extruded bacteria beyond the apical foramen. However, this study showed that Mtwo multifile rotary system extruded fewer bacteria. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study was to test the effect of new protocol of glide path preparation by 20/0.04 rotary file on apical extrusion of debris when instrumenting fine curved mesial canals in mandibular molars with Self-adjusting File (SAF) and compare it to a glide path prepared by 20/0.02 hand K-file and rotary OneShape (OS) and reciprocating WaveOne (WO) file instrumentation. Materials and Methods: Sixty mandibular molars with curved mesial roots were selected and randomly divided into three groups (n = 20) for instrumentation. In two groups, glide path was prepared using 20/0.02 K-file for instrumentation by OS (size 25/0.06 taper) and WO (size 25/0.08 taper) files; in the remaining group, 20/0.04 rotary file was used for glide path preparation and instrumented by SAF (1.5 mm). The debris extruded during instrumentation was collected in preweighed Eppendorf tubes and stored in an incubator at 70°C for 5 days. Tubes containing the dry extruded debris were then weighed. One-way analysis of variance (ANOVA) was applied to the weights obtained, followed by Tukey's post hoc test for multiple comparison. Results: The mean debris (g) extruded apically was 0.000651 ± 0.000291, 0.000823 ± 0.000319, and 0.000473 ± 0.000238 for Group 1 (20/0.02 + OS), Group 2 (20/0.02 + WO), and Group 3 (20/0.04 + SAF), respectively. The groups exhibited a significant difference (P < 0.01; ANOVA). Group 3 resulted in least debris extrusion compared to Groups 1 and 2 (P < 0.01; Tukey's post hoc test). Conclusion: Glide path prepared to size 20/0.04 and SAF 1.5 mm instrumentation produce less debris in curved mesial canals of mandibular molars, compared to glide path established by 20/0.02 and instrumentation by OS and WO files. [ABSTRACT FROM AUTHOR]

Background: All endodontic instrumentation systems tested so far, promote apical extrusion of debris, which is one of the main causes of postoperative pain, flare ups, and delayed healing. Objectives: Of this meta-analysis was to collect and analyze in vitro studies quantifying apically extruded debris while using Hand ProTaper (manual), ProTaper Universal (rotary), Wave One (reciprocating), and self-adjusting file (SAF; vibratory) endodontic instrumentation systems and to determine methods which produced lesser extrusion of debris apically. Methodology: An extensive electronic database search was done in PubMed, Scopus, Cochrane, LILACS, and Google Scholar from inception until February 2016 using the key terms "Apical Debris Extrusion, extruded material, and manual/rotary/ reciprocating/SAF systems." A systematic search strategy was followed to extract 12 potential articles from a total of 1352 articles. The overall effect size was calculated from the raw mean difference of weight of apically extruded debris. Results: Statistically significant difference was seen in the following comparisons: SAF < Wave One, SAF < Rotary ProTaper. Conclusions: Apical extrusion of debris was invariably present in all the instrumentation systems analyzed. SAF system seemed to be periapical tissue friendly as it caused reduced apical extrusion compared to Rotary ProTaper and Wave One. [ABSTRACT FROM AUTHOR]

Background: The type of instrument affects the amount of debris extruded. The aim of this study was to compare the effect of retreatment systems and supplementary file application on the amount of apical debris extrusion. Materials and Methods: Forty-eight extracted mandibular premolars with a single canal and similar length were selected. The root canals were prepared with the ProTaper Universal system with a torque-controlled engine. The root canals were dried and were obturated using Gutta-percha and sealer. The specimens were randomly divided into four equal groups according to the retreatment procedures (Group 1, Mtwo retreatment files; Group 2, Mtwo retreatment files + Mtwo rotary file #30 supplementary file; Group 3, ProTaper Universal retreatment (PTUR) files; and Group 4, PTUR files + ProTaper F3 supplementary file). The extruded debris during instrumentation were collected into preweighed Eppendorf tubes. The amount of apically extruded debris was calculated by subtracting the initial weight of the tube from the final weight. Three consecutive weights were obtained for each tube. Results: No statistically significant difference was found in the amount of apically extruded debris between Groups 1 and 3 (P = 0.590). A significant difference was observed between Groups 1 and 2 (P < 0.05), and between Groups 3 and 4 (P < 0.05). Conclusions: The use of supplementary file significantly increased the amount of apically extruded debris. [ABSTRACT FROM AUTHOR]

Background: Postoperative inflammation and endodontic failure occur due to apical extrusion of debris. Aim: To evaluate the amount of apically extruded debris after preparation of straight root canals in extracted human teeth using three rotary systems. Materials and Methods: Sixty single-rooted human teeth with single root canal and apical foramen were selected and randomly divided into three experimental groups (n = 20) according to the rotary system used: Group 1 - ProTaper, Group 2 - Revo-S, Group 3 - WaveOne. Apical enlargement was done up to size 40/0.06 for Groups 1 and 2 and 40/0.08 for Group 3. For debris collection, each tooth was held in a preweighed Eppendorf tube fixed inside a glass vial through rubber plug. After instrumentation, each tooth was separated from the Eppendorf tube and the debris adhering to the root surface was collected by washing the root with 1 mL of bi-distilled water and incubated at 70°C for 5 days. The dry weight of extruded debris was weighed in an electronic balance. Statistical Analysis: The mean weights of extruded debris were statistically analyzed using GraphPad prism version 6 and the intergroup comparison was done using unpaired t-test. Results: There was a statistically significant difference in the mean debris score among all the three groups - ProTaper (0.00065 g), Revo-S (0.00045 g) and WaveOne (0.00089 g). Conclusion: Revo-S system was associated with significantly less debris extrusion compared with ProTaper or WaveOne. [ABSTRACT FROM AUTHOR]

Background/Aim: To compare apically extruded debris using ProTaper Universal (PTU), ProTaper Next (PTN), WaveOne (WO), Twisted File (TF), M-Two (MT), and Revo-S (RS) after determining the working length (WL) with root ZX. Materials and Methods: Seventy-two teeth were selected. The WL determination was performed with root ZX. The teeth were divided into six experimental groups, randomly. In groups, root canals were prepared with PTU to size F4/0.06, with PTN to size X4/0.06, with WO to size 40/0.08, with TF to size 40/0.04, with MT to size 40/0.06, and with RS to size AS40/0.06. After preparations were completed, final irrigation was performed with 2 mL distilled water, and a total of 10 mL of distilled water was used in each tooth. Tubes were stored in an incubator at 68°C for 5 days to evaporate the distilled water before weighing the dry debris. Data were analyzed by the Mann–Whitney U-test. Results: The RS group led to the highest amount of extruded debris, however, WO led to the least amount of extruded debris. There was no statistically difference among the groups (P > 0.05). Conclusions: The authors conclude that the results obtained might depend on the apex locator used to determine the WL. [ABSTRACT FROM AUTHOR]

Aims: The purpose of this ex vivo study was to evaluate and compare the weight of debris and volume of irrigant extruded apically from teeth using different preparation techniques. Subjects and Methods: Thirty extracted human mandibular premolars with single canals and similar lengths were instrumented using hand ProTaper F2 (25, 0.08; Dentsply Maillefer, Ballaigues, Switzerland), M-two (25, 0.06; VDW, Munich, Germany) and WaveOne Primary (25, 0.08; Dentsply Maillefer, Ballaigues, Switzerland). Debris and irrigant extruded during instrumentation were collected into preweighed Eppendorf tubes. The volume of the irrigant was measured, and then the tubes were stored in an incubator at 70°C for 2 days. The Eppendorf tubes were weighed to obtain the final weight when the extruded debris was included. Three consecutive weights were obtained for each tube. Statistical Analysis Used: Data were statistically analyzed by one-way analysis of variance and Student's t-test. Results: There were no statistically significant differences among the groups. The WaveOne reciprocating system showed the maximum amount of apical extrusion of debris and irrigant among all the groups. The least amount of debris and irrigant was observed in ProTaper hand instrument (P > 0.05). Conclusion: All instrumentation techniques were associated with debris and irrigant extrusion. [ABSTRACT FROM AUTHOR]

Aim: The present ex vivo study aimed to evaluate the debris extrusion after instrumenting the root canals by three different files systems. Materials and Methods: Sixty extracted human mandibular premolars with single canals were selected and randomly divided into three groups (n = 20) for instrumentation with three different files. Group 1: Wave One (primary) single reciprocating file (WO; Dentsply Maillefer, Ballaigues, Switzerland) (25/08), Group 2: Self-adjusting file (SAF; ReDent-Nova, Ra'anana, Israel) (1.5 mm), and Group 3: ProTaper NEXT X1 and X2 (PTN; Dentsply Tulsa Dental, Tulsa, OK) (25/06). Debris extruding by instrumentation were collected into pre-weighed Eppendorf tubes. These tubes were then stored in an incubator at 70°C for 5 days. The tubes were then weighed to obtain the final weight, with the extruded debris. Statistical analysis for the debris extruded apically was performed using one-way analysis of variance and post hoc Tukey's test. Results: The statistical analysis showed a significant difference between all the three groups tested (P < 0.01). The following post hoc Tukey's test confirmed that Group 2 (SAF) exhibited significantly least (P < 0.01) debris extrusion between the three groups tested. Conclusions: The SAF resulted in significantly less extrusion of debris when compared to reciprocating WO and rotary PTN. [ABSTRACT FROM AUTHOR]

Background and Aims: Extrusion of any debris during endodontic treatment may potentially cause post-operative complications such as flare-ups. The purpose of this in vitro study was to assess the amount of apically extruded debris during the root canal preparation using rotary and reciprocating nickel-titanium instrumentation systems. Materials and Methods: In this study, 60 human mandibular first premolars were randomly assigned to 3 groups (n = 20 teeth/group). The root canals were instrumented according to the manufacturers' instructions using the Reciprocating singlefile system WaveOne™ (Dentsply Maillefer, Ballaigues, Switzerland) and full-sequence rotary Hyflex CM™ (Coltene Whaledent, Allstetten, Switzerland) and ProTaper™ (Dentsply Maillefer, Ballaigues, Switzerland) instruments. The canals were then irrigated using bidistilled water. The debris that was extruded apically was collected in preweighed eppendorf tubes and assessed with an electronic balance and compared. Statistical Analysis Used: The debris extrusion was compared and statistically analyzed using analysis of variance and the post hoc Student-Newman-Keuls test. Results: The WaveOne™ and ProTaper™ rotary instruments produced significantly more debris compared with Hyflex CM™ rotary instruments (P < 0.05). Conclusions: Under the conditions of this study, all systems that were used resulted in extrusion of apical debris. Full-sequence rotary instrumentation was associated with less debris extrusion compared with the use of reciprocating single-file systems [ABSTRACT FROM AUTHOR]

Aim: This aim of this study was to evaluate the number of bacteria extruded apically during root canal preparation using Four Rotary instrumentation techniques. Materials and Methods: A total of 50 extracted mandibular premolars were selected, access cavities prepared and inserted in to rubber stoppers of 10 mL glass vial. Root canals were contaminated with a suspension of Enterococcus faecalis (E. faecalis) American Type Culture Collection (ATCC)29212 and incubated for 24 h at 37°C. Debris extruded from the apical foramen during instrumentation was collected into vials. The numbers of Colony-forming units were determined for each sample. Statistical Analysis: The data obtained were analyzed using the one-way ANOVA followed by post-hoc tukey's test with a P=0.05 as the level for statistical significance. Results: Results suggested a statistically significant difference in the number of colony forming units between four experimental rotary Nickel-Titanium instrumentation groups (P<0.001). Conclusion: Although, extrusion of bacteria was found in all the experimental groups. There was less bacterial extrusion in K3 Group while more bacterial extrusion was seen in Mtwo Group. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the bacteria extruded apically during root canal preparation using two hand and rotary instrumentation techniques. Materials and Methods: Eighty freshly extracted mandibular premolars were mounted in bacteria collection apparatus. Root canals were contaminated with the pure culture of Enterococcus fecalis (ATCC 29212) and dried at 37°C for 24 h. Bacteria extruded were collected, incubated in brain heart infusion agar for 24 h at 36°C and the colony forming units (CFU) were counted. Statistical Analysis: The mean number of colony forming units were calculated by One-way ANOVA and comparison between the groups made by multiple comparison (Dunnet D) test. Results: The step-back technique extruded highest number of bacteria in comparison to other hand and rotary Ni-Ti systems. Conclusion: Under the limitation of this study all hand and rotary instrumentation techniques extruded bacteria. Among all the instrumentation techniques step-back technique extruded more number of bacteria and K-3 system the least. Further in vivo research in this direction could provide more insight into the biologic factors associated and focus on bacterial species that essentially play a major role in post instrumentation flare-ups. [ABSTRACT FROM AUTHOR]

Aim: To evaluate and compare the amount of debris and irrigant extruded quantitatively by using two hand and rotary nickel–titanium (Ni–Ti) instrumentation techniques. Materials and Methods: Eighty freshly extracted mandibular premolars having similar canal length and curvature were selected and mounted in a debris collection apparatus. After each instrument change, 1 ml of distilled water was used as an irrigant and the amount of irrigant extruded was measured using the Meyers and Montgomery method. After drying, the debris was weighed using an electronic microbalance to determine its weight. Statistical analysis used: The data was analyzed statistically to determine the mean difference between the groups. The mean weight of the dry debris and irrigant within the group and between the groups was calculated by the one-way ANOVA and multiple comparison (Dunnet D) test. Results: The step-back technique extruded a greater quantity of debris and irrigant in comparison to other hand and rotary Ni–Ti systems. Conclusions: All instrumentation techniques extrude debris and irrigant, it is prudent on the part of the clinician to select the instrumentation technique that extrudes the least amount of debris and irrigant, to prevent a flare-up phenomena. [ABSTRACT FROM AUTHOR]

Background: Sodium hypochlorite (NaOCl) is the most widely used endodontic irrigant because of its excellent antimicrobial, organic tissue dissolving, and lubricating properties. However, it is highly cytotoxic to the periapical tissues. Aim: This study evaluated in vitro the extrusion of 5.25% NaOCl through the apical foramina of mesiobuccal (MB) root canals of maxillary first molars in two experimental conditions: Before apical debridement and after apical debridement with different instrument sizes to ensure direct access to the apical foramen (apical patency). Materials and Methods: Coronal accesses were prepared in 17 teeth and the apical foramina of the distobuccal and palatal root canals were sealed. The teeth were held in acrylic receptacles with the roots turned upwards to reproduce their position in the maxillary dental arch. The receptacles were filled with a starch/KI solution (a reagent that changes its color to blue after contacting NaOCl) covering the roots. The experiment had two phases: P1: Irrigation of the MB canals with 5.25% NaOCl without previous establishment of apical patency; P2: Canal irrigation after use of size 10 K-file and size 15 Flexofile as patency files. Only specimens with no NaOCl extrusion in P1 were assigned to P2. NaOCl was delivered pressureless at the canal entrance. The moment that the starch/KI solution contacted NaOCl was captured on digital photographs. Results and Conclusions: There was no NaOCl extrusion in nine specimens in P1, but all of these teeth had irrigant extrusion in P2. The 5.25% NaOCl used as an endodontic irrigant showed great capacity to extrude beyond both intact and small-sized apical foramina of MB root canals of maxillary first molars. [ABSTRACT FROM AUTHOR]

Aim: To comparatively evaluate the amount of apically extruded debris when ProTaper hand, ProTaper rotary and ProFile systems were used for the instrumentation of root canals. Materials and Methods: Thirty minimally curved, mature, human mandibular premolars with single canals were randomly divided into three groups of ten teeth each. Each group was instrumented using one of the three instrumentation systems: ProTaper hand, ProTaper rotary and ProFile. Five milliliters of sterile water were used as an irrigant. Debris extruded was collected in preweighed polyethylene vials and the extruded irrigant was evaporated. The weight of the dry extruded debris was established by comparing the pre- and postinstrumentation weight of polyethylene vials for each group. Statistical Analysis: The Kruskal-Wallis nonparametric test and Mann-Whitney U test were applied to determine if significant differences existed among the groups (P < 0.05). Results: All instruments tested produced a measurable amount of debris. No statistically significant difference was observed between ProTaper hand and ProFile system (P > 0.05). Although ProTaper rotary extruded a relatively higher amount of debris, no statistically significant difference was observed between this type and the ProTaper hand instruments (P > 0.05). The ProTaper rotary extruded significantly more amount of debris compared to the ProFile system (P < 0.05). Conclusion: Within the limitations of this study, it can be concluded that all instruments tested produced apical extrusion of debris. The ProTaper rotary extruded a significantly higher amount of debris than the ProFile. [ABSTRACT FROM AUTHOR]