Search

The purpose of this study was to compare the impact of different irrigation protocols on debris extrusion. Single‐rooted teeth were distributed into groups based on the irrigation protocols (n = 40): 2.5% NaOCl (biomechanical preparation: 20 mL and final irrigation: 5 mL); 2.5% NaOCl (biomechanical preparation: 20 mL) + 17% EDTA (final irrigation: 2 mL) + 2.5% NaOCl (final irrigation: 3 mL); and a mixture of 5% NaOCl +18% HEDP (biomechanical preparation: 20 mL and final irrigation: 5 mL). The canals were prepared using a reciprocating instrument size 40/0.06. For final irrigation, the groups were reassigned based on the agitation methods (n = 10): (a) no agitation; (b) ultrasonic; (c) sonic; and (d) continuous rotation. The control group (n = 10) received saline solution without agitation. The amount of debris extruded was measured by weight and analysed using One‐way ANOVA (α < 0.05). The subgroups treated with NaOCl + HEDP mixture showed a significantly higher amount of extruded debris (p < 0.05), while there was no difference among agitation methods in all groups (p > 0.05). [ABSTRACT FROM AUTHOR]

This study compared standard needle irrigation, passive ultrasonic irrigation, XP‐Endo Finisher and Easy Clean in the apical extrusion of sodium hypochlorite (NaOCl) in a model simulating immature teeth. Ten bovine teeth were maintained in suspension in a container with the apical portion in contact with 0.2% agarose gel containing 0.1% metacresol purple. The canals were irrigated with 2.5% NaOCl, according to each irrigation protocol. After 3 min, apical extrusion of NaOCl was observed by the colour gel change when in contact with NaOCl. The containers were photographed, and the NaOCl extrusion area was measured. All protocols showed NaOCl extrusion, providing similar area (P > 0.05). Considering the similarity among the studied protocols, all of them can be considered during the endodontic treatment of immature teeth. Further studies on the particularities of immature teeth should be performed to evaluate cell viability, cleaning efficiency, disinfection capacity and dentin removal promoted by the irrigation protocols. [ABSTRACT FROM AUTHOR]

Aim: A laboratory study to determine the apical pressure generated by seven canal irrigation methods in an anterior tooth with an open apex. Methodology: Canal 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). Results: EndoVac, 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. Conclusions: In 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. [ABSTRACT FROM AUTHOR]

This study compared the amount of apically extruded debris associated with different heat‐treated Ni‐Ti rotary systems during the preparation of curved root canals of mandibular molars. Sixty extracted human mandibular molars were selected. EdgeFile, K3XF, OneCurve (OC) and ROTATE files were used to prepare both mesial canals of teeth. The initial weight of each Eppendorf tube to be used was calculated using an analytical balance prior to instrumentation. After instrumentation, the tubes were then stored for 5 days in an incubator at 70°C. Each tube was reweighed, and the weight of the dry extruded debris was established by subtracting the pre‐instrumentation and post‐instrumentation weight of the Eppendorf tubes for each group. All files caused apical extrusion of debris. There was no statistical difference between the ROTATE, EdgeFile, OC and K3XF systems (P > 0.05). All the heat‐treated Ni‐Ti rotary systems led to similar apical debris extrusion during the canal preparation. [ABSTRACT FROM AUTHOR]

The present study aimed to compare the apically extruded debris produced during glide path preparation using R‐Pilot (RP), WaveOne Gold Glider (WGG) and ProGlider (PG) with the subsequent preparation using Reciproc Blue in curved root canals. Mesial roots of mandibular molars with angle of curvature between 25° and 35° were selected (n = 20). The Myers and Montgomery method was used to collect and assess apically extruded debris. The glide path was prepared either manually with K‐file, ProGlider, R‐Pilot or WaveOne Gold Glider. Manual preparation group produced the highest amount of apically extruded debris (P < 0.05), while all groups caused debris extrusion. There were no significant differences among the extruded debris caused by RP, PG and WGG groups (P > 0.05). Apically extruded debris produced by engine‐driven reciprocational or continuous rotational single file glide path instruments was similar, whereas manual glide path preparation was associated with the greatest amount of extruded debris. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate if apical negative pressure ( ANP) irrigation prevents the apical extrusion of debris and irrigant compared with conventional needle irrigation through a systematic review and meta-analysis. A computer search of dental literature was performed using four different databases. A combination of the terms 'apical negative pressure', 'endovac', 'apical extrusion', 'extrusion' and 'endodontics' was used. Studies that used extracted human teeth with a mature apex and that evaluated the apical extrusion of debris and/or irrigating solution were included. After an evaluation of the full studies according to the eligibility criteria, eight studies were critically analysed and subjected to quality assessment and risk of bias. Only four studies that evaluated extrusion of irrigant were considered as having high methodological quality and were subjected to a meta-analysis. Studies evaluating extrusion of debris did not have sufficient methodological quality to be subjected to the meta-analysis. The forest plot indicated that ANP irrigation prevents the risk of irrigant extrusion compared with conventional irrigation ( OR 0.07 [95% CI 0.02-0.20]; P < 0.00001). This systematic review and meta-analysis showed that ANP prevents the apical extrusion of irrigant. There is no evidence if this type of irrigation prevents the extrusion of debris. [ABSTRACT FROM AUTHOR]

Aim To compare the amount of apically extruded debris and of remaining filling material during the removal of root canal filling material using three rotary NiTi retreatment instruments or Hedström files. Methodology Ninety-six severely curved human molars of both jaws were selected. The root canals were prepared to size X2 (tip size 25, .06 taper) using the ProTaper Next system (Dentsply Sirona, Ballaigues, Switzerland), filled with gutta-percha and AH Plus sealer (Dentsply De Trey, Konstanz, Germany) and then randomly divided into four experimental groups ( n = 24 each) with two subgroups of maxillary and mandibular teeth each. An experimental model was used as a phantom head to simulate the upper and lower jaws. The root filling materials were removed with one of the following files using a crown-down preparation technique: I. Hedström files (H-files) ( VDW, Munich, Germany), II. R-Endo (Micro-Mega, Besançon, France), III. Reciproc ( VDW) and IV. ProTaper Universal Retreatment system ( PTU-R) (Dentsply Maillefer). Apically extruded material was collected in vials, which were weighed with a microbalance (10−5 g) before and after the retreatment. The area of residual filling material in the coronal, middle and apical root level was assessed using digital analysis. These data were analysed statistically using ANOVA and the Kruskal-Wallis test. Results Reciproc was associated with significantly less extruded debris than the H-files ( P = 0.009). No significant differences were detected amongst the four retreatment techniques concerning residual filling material ( P = 0.082). The amount of extruded debris and areas of remaining filling material were not correlated ( P = 0.901). Location of teeth in the maxilla or mandible had no impact on the amount of extruded debris within each instrument group ( P = 0.609). However, when teeth were evaluated in general irrespective of the instruments, significantly more debris was extruded in the mandibular location ( P < 0.001). Conclusions All retreatment systems were associated with apical extrusion of debris, but H-files extruded significantly more material than Reciproc. Remnants of filling material were observed in all samples with no significant differences between the four techniques. [ABSTRACT FROM AUTHOR]

Aim To compare the degree of fibre shedding by six brands of endodontic paper point when used for the paper point technique ( PPT) of working length confirmation. Methodology An in vitro model simulating the clinical use of paper points in PPT was used to assess the degree of fibre shedding of six brands of size 20, .02 taper paper point. Whilst observing the artificial terminal foramen with polarized light microscopy, the number of fibres shed directly (point inserted 1 mm beyond the terminal foramen) and indirectly (point inserted to length then a gutta-percha point inserted) was assessed. The degree of direct fibre shedding as a function of brand was analysed with Fisher's exact test and multiple pairwise comparisons. Indirect fibre shedding was analysed with Kruskal-Wallis and Wilcoxon rank-sum tests. Results All brands shed fibres both directly and indirectly, with a significant influence of brand on the proportion of fibres shed directly ( P < 0.0306) and on the mean number of fibres shed indirectly ( P < 0.0001). Post hoc analysis demonstrated a similar hierarchy of point integrity for both tests with Classic (UnoDent, Witham, UK) shedding significantly more than other brands and SS White (Gloucester, UK) and Antæos® ( VDW, Munich, Germany) shedding the least. Conclusion All brands of paper point may shed cellulose fibres both directly and indirectly with a significant influence of brand on the degree of fibre shedding. Further work should be undertaken to develop biocompatible absorbent dental points. [ABSTRACT FROM AUTHOR]

Aim To compare the amount of debris extruded apically during root canal retreatment using ProTaper, Mtwo and Reciproc instruments with hand H-files. Methodology In total, 60 freshly extracted human mandibular incisor teeth were used. All root canals were prepared with a Reciproc R25 file than filled with Gutta-percha and AH Plus sealer using cold lateral condensation before being assigned randomly to four groups ( n = 15 each). In group 1, root fillings were removed with the Protaper Universal retreatment system; ProTaper Universal F3 and F4 instruments were used for the final preparation. In group 2, root fillings were removed with the Mtwo retreatment system; Mtwo size 30, .06 taper, size 35, .06 taper and size 40, .06 taper files were used for the final preparation. In group 3, root fillings were removed with Reciproc R25 instruments; Reciproc R40 instruments were used for the final preparation. In group 4, the root fillings were removed with Gates Glidden burs and sizes 35, 30 and 25 H-files; for final preparation, a size 40 H-file was used. Glass vials were used for debris collection. The vials were weighed before and after Gutta-percha removal. Additionally, the times required for the retreatment procedures were recorded. Data were analysed statistically using one-way analysis of variance. Results The Reciproc system produced significantly smaller amounts of apical extruded debris than the other groups ( P < 0.05). There was no significant difference between the Mtwo, H-file and ProTaper groups. The ProTaper and Reciproc groups required significantly less time than the Mtwo and H-file groups ( P < 0.001). Conclusions Use of the reciprocating single file system resulted in the extrusion of significantly less debris compared with the full-sequence rotary NiTi instruments and hand filing. Use of the ProTaper and Reciproc instruments required less time for retreatment procedures than use of the Mtwo or H-file. [ABSTRACT FROM AUTHOR]

Aim The purpose of this study was to determine the effect of root canal dimensions, type of needle, and injection rate on the apical extrusion of an irrigant in a simulated root canal. Methods Ten students used two types of 28-gauge needles, to deliver 3 m L irrigant solution into artificial canals prepared in acrylic blocks to a standard size of ISO 25, 30, or 40 (0.06 taper; n = 10). Each block was preweighed to the nearest microgram before and after irrigation once the canal was dried with paper points. This was repeated with a syringe pump at a flow rate of 50, 100, 200 or 300 μ L/s with the needle inserted to a standard depth. Results Significant differences were observed between the side-vented and notched-end needles when the rate of irrigation was higher than 100 μ L/s, and when the apical size was below ISO 40 ( P < 0.001). The amount of extrusion was more variable and significantly higher when irrigation was performed manually, compared with the syringe pump groups. Conclusions Injection rates above 100 μ L/s increased the risk of extrusion, whereas increasing the apical canal size to ISO 40 reduced the amount of extrusion in all groups. The use of a side-vented needle negates the injection-rate effects. [ABSTRACT FROM AUTHOR]

Aim To compare apical extrusion of debris in canals prepared with two reciprocating file systems and two different irrigation systems. Methodology Forty single straight root canals in human mandibular pre-molars were prepared using Reciproc R40 ( REC) and WaveOne Large ( WO) instruments. Before preparation, the dimensions of a size 40 instrument from each system were measured under scanning electron microscopy ( SEM) at 80X. The teeth were randomly divided into four different groups of 10: REC and VPro EndoSafe ( REC/ VPro); WO/VPro; REC and conventional irrigation ( REC/CI); and WO/CI Eppendorf tubes containing a single tooth were weighed on an analytical balance to the nearest 0.1 mg before instrumentation. Irrigation was performed with a total volume of 8 mL of 2.5% sodium hypochlorite. After instrumentation, the teeth were removed from the Eppendorf tube and incubated at 37 °C for 15 days to evaporate the liquid. The tubes were weighed again, and the difference between the initial and final debris weights was calculated and statistically evaluated using analysis of variance (two-way anova) with a significance level of 0.05. Results No significant difference was observed between the VPro and CI irrigation systems ( P > 0.05). Apical extrusion of debris was confirmed in all samples, and extrusion was greater in the REC groups than in the WO groups ( P < 0.05). The WO file had a 20% smaller diameter at the tip (D0) than the measurement provided by the manufacturer. Conclusions All systems were associated with apical extrusion of debris. The WO system was associated with less extrusion than the REC system. The amount of extruded debris was independent of the irrigation system used and was related to the instrumentation technique. Morphological analysis of instruments using SEM revealed no correlation between the diameter provided by the manufacturer and the measured diameter for the WO Large file. [ABSTRACT FROM AUTHOR]

Aim To evaluate the apical extrusion of debris associated with several root canal preparation systems in vitro. Methodology Forty-five extracted human mandibular premolars with single canals and similar lengths were used. The root canals were instrumented using ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland), Twisted File (SybronEndo, Orange, CA, USA) or WaveOne (Dentsply Maillefer, Ballaigues, Switzerland). Debris extruded apically during instrumentation was collected into pre-weighed Eppendorf tubes. The Eppendorf tubes were then stored in an incubator at 70 °C for 5 days. The Eppendorf tubes were weighed to obtain the final weight of the Eppendorf tubes plus extruded debris. Three consecutive weights were obtained for each tube. The groups were compared using the Kruskal-Wallis one-way analysis of variance on Ranks and Tukey's test. Results The ProTaper Next group produced the highest mean extrusion value whilst WaveOne produced less debris compared with all the other instruments ( P > 0.05). There was a significant difference between the ProTaper Next and WaveOne group ( P < 0.05). Conclusions Apically extruded debris was associated with all instrumentation techniques. The WaveOne system extruded less debris compared with the Twisted File and ProTaper Next. [ABSTRACT FROM AUTHOR]

Aim To evaluate the influence of reciprocating single-file instrumentation with different working lengths ( WL) and apical preparation sizes on apical bacterial extrusion. Methodology Sixty-eight human single-rooted pre-molars were used. Conventional access cavities were prepared, and the root canals were contaminated with an Enterococcus faecalis suspension and incubated at 37°C for 30 days. Teeth were then divided into four groups of 15 specimens each (Reciproc size 25, .08 taper and Reciproc size 40, .06 taper instruments were used at the foramen; Reciproc size 25, .08 taper and Reciproc size 40, .06 taper instruments were used 1 mm short of the foramen). Positive and negative controls consisted of four infected and four uninfected pre-molars that were instrumented according to each experimental group. Bacteria extruded from the apical foramen during instrumentation were collected into vials containing 0.9% NaCl. The microbiological samples were then incubated in a brain-heart agar medium for 24 h. The resulting bacterial titre, in colony-forming units ( CFU) per mL, was determined, and these data were analysed using a Wilcoxon matched-pairs signed rank test and a Kruskal-Wallis H-test. The level of significance was set at α = 0.05. Results No growth was observed in the negative control group. All positive controls demonstrated bacterial growth after the experimental time interval. No significant difference was found in the number of CFU amongst all experimental groups ( P = 0.95). Conclusions This study showed that the WL and the apical preparation size did not have a significant effect on bacterial extrusion when performing reciprocating instrumentation. [ABSTRACT FROM AUTHOR]

Aim To assess and compare the amount of extruded debris after canal preparation using ProTaper Universal and ProTaper Next files. Methodology Forty extracted mandibular premolars with single canals and of similar lengths were instrumented using the ProTaper Universal F3 or the ProTaper Next X3. The extruded debris during instrumentation was collected into pre-weighed Eppendorf tubes. The tubes were stored in an incubator for 5 days. The tubes were weighed to obtain the final dry weight of the extruded debris. The amount of apically extruded debris was calculated by subtracting the initial weight of the tube from the final weight. The distribution of the data was examined using the Shapiro-Wilks test. Continuous variables were compared with an independent-samples t-test for two groups. Results All specimens were associated with apical debris extrusion. The ProTaper Universal group produced a significantly greater amount of debris extrusion ( P < 0.001). The lowest and highest amounts of debris for PTU and PTN groups were recorded as 0.00117-0.00165 g and 0.00017-0.00067 g, respectively. Conclusion ProTaper Next files was associated with significantly less extruded apical debris when compared to ProTaper Universal files. [ABSTRACT FROM AUTHOR]

Aim To evaluate ex vivo, apical bacterial extrusion associated with two reciprocating single-file systems (WaveOne and Reciproc) compared with a conventional multifile rotary system (BioRace). Methodology Forty-five human single-rooted mandibular incisors were used. Endodontic access cavities were prepared, and root canals were contaminated with an Enterococcus faecalis suspension. Following incubation at 37 °C for thirty days, the contaminated teeth were divided into three groups of 15 specimens each (G1 - Reciproc, G2 - WaveOne and G3 - BioRace). Positive and negative controls consisted of 5 infected teeth and 3 uninfected incisors that were instrumented with one of the tested NiTi systems, respectively. Bacteria extruded from the apical foramen during instrumentation were collected into vials containing 0.9% NaCl. The microbiological samples were taken from the vials and incubated in brain heart agar medium for 24 h. The resulting bacterial titre, in colony-forming units ( CFU) per mL, was determined, and these data were analysed by Wilcoxon matched-pairs signed rank test and Kruskal-Wallis H-test. The level of significance was set at α = 0.05. Results No significant difference was found in the number of CFU between the two reciprocating systems ( P = 0.41). The conventional multifile rotary system group was associated with significantly higher CFU than both of the two reciprocating groups ( P = 0.01). Conclusions All instrumentation systems extruded bacteria beyond the foramen. However, both reciprocating single-file systems extruded fewer bacteria apically than the conventional multifile rotary system. [ABSTRACT FROM AUTHOR]

Aim To evaluate (i) the effect of irrigant flow rate, needle type, needle insertion depth and apical constriction diameter and (ii) the effect of ultrasonic, sonic and manual dynamic agitation on irrigant extrusion using a recently introduced method. Methodology Thirty-two human teeth with a straight root canal were prepared to size 35, 0.06 taper and assigned to group A or B. The apical constriction diameter was 0.15-0.25 mm. Specimens were mounted on a plastic vial filled with distilled water to simulate a periapical lesion. A point-conductivity probe was used to determine the volume of irrigant extruded into the vial. Within group A, NaOCl was delivered at 0.14 or 0.26 mL s−1 by an open-ended or a closed-ended needle at 1 or 3 mm short of working length (WL). In group B, NaOCl was agitated at high or low power either by an ultrasonically or sonically oscillating instrument inserted at 1 or 3 mm short of WL or by manual push-pull strokes of a gutta-percha cone. Results were analysed by repeated-measures anovas, at 0.05 significance. Results An increase in the flow rate resulted in increased extrusion ( P < 0.001). The open-ended needle extruded significantly more irrigant than the closed-ended ( P < 0.001). Extrusion decreased as needles moved away from WL ( P < 0.001). The effect of apical constriction diameter was not significant ( P > 0.454). Manual dynamic agitation extruded significantly more irrigant than sonic and ultrasonic agitation ( P < 0.001). Conclusions Irrigant flow rate, needle type and insertion depth and agitation technique had a significant effect on extrusion. [ABSTRACT FROM AUTHOR]

Extrusion of intracanal debris as well as irrigants is a common occurrence during root canal treatment, and no instrument or technique has thoroughly solved this problem. Because flare-ups may arise with any irritation directed towards periapical tissues, a shaping or irrigation technique should minimize the risk of apical extrusion, even though it may not be prevented. There has been a rapid evolution of root canal instruments and irrigation systems through the last decade, and many have been assessed for their debris extrusion potential. The purpose of this review was to identify publications regarding the evaluation of debris, bacteria and irrigant extrusion during root canal treatment. A Pub Med, Ovid and MEDLINE search was conducted using the keywords 'apical extrusion', 'debris extrusion' and 'endodontic treatment'. The literature search extended over a period of more than 30 years up to 2012. Content of the review was limited to apical extrusion of debris and irrigants, extrusion of liquid by irrigation methods and bacterial extrusion. Issues relevant to apical extrusion were obtained by further search in the reference sections of the retrieved articles. The review provides an update on the current status of apical extrusion. [ABSTRACT FROM AUTHOR]

Aim To compare the weight of apically extruded debris associated with canal shaping using K-files, and the Revo- S system using two different needle tips, open-ended and side-vented. Methodology Forty freshly extracted mandibular premolar teeth were divided into four groups as follows; Group 1a: Hand instrumentation of root canal with open-ended needle used to provide irrigation, Group 1b: Hand instrumentation with a two side-port needle, Group 2a: Revo- S preparation with open-ended needle, Group 2b: Revo- S preparation with a two side-port needle. One Eppendorf tube for each tooth was weighed with a 0.0001 electronic weighing machine before instrumentation procedures. During instrumentation, irrigation was performed after every instrument with 1 mL distilled water. On completion of the preparation, teeth were removed from the Eppendorf tubes. All of the tubes were incubated at 37 °C for 15 days, to evaporate the irrigant. After the incubation period, tubes were weighed again. The difference between pre-and post-debris weights was calculated, and statistical evaluation was performed using analysis of variance at 0.05 level of significance. Results No statistically significant difference was observed between K-files and the Revo S system. A significant difference was observed between needles ( P < 0.05). Open-ended needles were associated with significantly more debris than side-vented needles ( P < 0.05). Conclusions Both hand and rotary canal instrumentation resulted in extrusion of debris beyond the apical foramen. No significant difference was observed between K-files and Revo- S system. Open-ended needles were associated with significantly more extruded debris than two side-port needles. [ABSTRACT FROM AUTHOR]

The aim of the present study was to conduct a systematic review and critical analysis of published data on irrigant extrusion to identify factors causing, affecting or predisposing to irrigant extrusion during root canal irrigation of human mature permanent teeth. An electronic search was conducted in Cochrane Library, LILACS, PubMed, Sci ELO, Scopus and Web of Knowledge using a combination of the terms 'irrigant', 'rinse', 'extrusion', 'injection', 'complication', 'accident', 'iatrogenic', 'root canal', 'tooth' and 'endodontic'. Additional studies were identified by hand-searching of six endodontic journals and the relevant chapters of four endodontic textbooks, resulting in a total of 460 titles. No language restriction was imposed. After applying screening and strict eligibility criteria by two independent reviewers, 40 case reports and 10 ex vivo studies were included in the review. A lack of clinical studies focusing on irrigant extrusion during root canal irrigation was evident. The reviewed case reports focused mainly on the clinical manifestations and management of the accidents and did not provide adequate details on the possible factors that may influence irrigant extrusion. The data from the included e x vivo studies were inconclusive due to major methodological limitations, such as not simulating the presence of periapical tissues and not assessing the validity of irrigant detection methods. The extensive variability in the protocols employed hindered quantitative synthesis. The choice of factors investigated in ex vivo studies seems not to have been driven by the available clinical evidence. These issues need to be addressed in future studies. [ABSTRACT FROM AUTHOR]

Aim (i) To introduce a new method of quantifying extruded irrigant during root canal irrigation ex vivo. (ii) to evaluate the effect of periapical tissue simulation and pressure equalization and (iii) to determine the effect of needle type, apical preparation size and apical constriction diameter on irrigant extrusion. Methodology Sixteen human single-rooted teeth were sequentially prepared to sizes 25-45, 0.06 taper and mounted on a plastic vial simulating a periapical lesion. The apical constriction diameter was standardized to 0.15-0.35 mm. The vial was filled with distilled water or air and was either open to the environment or closed. A point-conductivity probe was used to determine the volume of extruded irrigant into the vial. Na OCl was delivered by an open-ended or a closed-ended needle at 3 mm short of working length. Results were analysed by two 3-way repeated-measures ANOVAs Results The open-ended needle extruded significantly more irrigant than the closed-ended in the majority of cases ( P < 0.002). An increase in the apical size was related to decreased irrigant extrusion ( P < 0.024). The effect of constriction diameter was not significant. The water-closed and water-open methods were related to less extrusion than the air-closed and air-open methods, respectively ( P < 0.005). Open systems (water-open, air-open) allowed extrusion of larger amounts of irrigant than corresponding closed systems (water-closed, air-closed) ( P < 0.005). Conclusions The conductivity probe is a reliable method for real-time quantification of irrigant extrusion ex vivo. Not simulating tissue resistance in ex vivo experiments may lead to significant overestimation of irrigant extrusion. [ABSTRACT FROM AUTHOR]

Aim To evaluate the number of bacteria extruded apically from extracted teeth ex vivo after canal instrumentation using a manual technique and three engine-driven techniques utilizing nickel–titanium instruments (K3, RaCe, and FlexMaster). Methodology Seventy extracted human mandibular premolar teeth with similar dimensions were used. Access cavities were prepared and root canals were then contaminated with a suspension of Enterococcus faecalis and then dried. The contaminated roots were divided into four experimental groups of 15 teeth each and one control group of 10 teeth. G1. RaCe group: the root canals were instrumented using RaCe instruments. G2. K3 group: the root canals were instrumented using K3 instruments. G3. FlexMaster group: the root canals were instrumented using FlexMaster instruments. G4. Manual technique group: the root canals were instrumented using K-type stainless steel instruments. G5. Control group: no instrumentation was attempted. Bacteria extruded from the apical foramen during instrumentation were collected into vials. The resultant microbiological samples were removed from the vials and then incubated in culture media for 24 h. The number of colony-forming units (CFU) was determined for each sample. The data obtained were analysed using the Kruskal–Wallis one-way analysis of variance and Mann–Whitney U-tests, with α = 0.05 as the level for statistical significance. Results There was a significant difference between experimental-control and engine-driven-manual technique groups ( P < 0.05). The manual technique was associated with the greatest extrusion of microorganism. Conclusions All instrumentation techniques extruded intracanal bacteria apically. No significant difference was found in the number of CFU among the engine-driven techniques; manual techniques extruded significantly more microorganisms. [ABSTRACT FROM AUTHOR]

Aim To investigate the efficiency of a hydrodynamic irrigation system compared with conventional cleansing techniques in root canals. Methodology Forty-five freshly extracted single-rooted teeth were de-coronated and their root canals were enlarged to size 30 at the apex. The teeth were randomly divided into three groups ( n = 15) for the final rinsing sequence using 2% NaOCl plus acid fuchsin: group I: static application of irrigant, 3 min; group II: flushing with a syringe; 5-mL NaOCl, 1 min; group III: RinsEndo®-system; 5-mL NaOCl, 50 s. Apical extrusion was documented photographically. The roots were sectioned at 2, 4, 6 and 8 mm from their apices and the penetration depths of dye into dentine measured, using a stereomicroscope. Wilcoxon's test and Pearson's chi-squared test were employed to prove statistic relevance. Results Greater dye penetration depth into the dentinal tubules was achieved when employing hydrodynamic rinsing procedures. Using this technique, 23% of the specimens were penetrated for more than 50% of their dentine thickness, whereas the results for flushing with a syringe were 12% (static application, 7%). No penetration of dentine occurred in 63% of specimens with static application, 39% flushing with a syringe and 15% using the hydrodynamic system ( P < 0.05 Pearson's chi-squared test). Apical extrusion occurred more frequently after hydrodynamic rinsing (extruded specimens: RinsEndo® = 80%; static application/flushing with a syringe = 13%; P < 0.05 Pearson's chi-squared test). Conclusions Hydrodynamic rinsing demonstrated an improvement over conventional methods in terms of dentine penetration of a dye marker. A higher risk of apical extrusion with the RinsEndo®-system was evident. [ABSTRACT FROM AUTHOR]

Aim To investigate the efficiency of a hydrodynamic irrigation system compared with conventional cleansing techniques in root canals. Methodology Forty-five freshly extracted single-rooted teeth were de-coronated and their root canals were enlarged to size 30 at the apex. The teeth were randomly divided into three groups ( n = 15) for the final rinsing sequence using 2% NaOCl plus acid fuchsin: group I: static application of irrigant, 3 min; group II: flushing with a syringe; 5-mL NaOCl, 1 min; group III: RinsEndo®-system; 5-mL NaOCl, 50 s. Apical extrusion was documented photographically. The roots were sectioned at 2, 4, 6 and 8 mm from their apices and the penetration depths of dye into dentine measured, using a stereomicroscope. Wilcoxon's test and Pearson's chi-squared test were employed to prove statistic relevance. Results Greater dye penetration depth into the dentinal tubules was achieved when employing hydrodynamic rinsing procedures. Using this technique, 23% of the specimens were penetrated for more than 50% of their dentine thickness, whereas the results for flushing with a syringe were 12% (static application, 7%). No penetration of dentine occurred in 63% of specimens with static application, 39% flushing with a syringe and 15% using the hydrodynamic system ( P < 0.05 Pearson's chi-squared test). Apical extrusion occurred more frequently after hydrodynamic rinsing (extruded specimens: RinsEndo® = 80%; static application/flushing with a syringe = 13%; P < 0.05 Pearson's chi-squared test). Conclusions Hydrodynamic rinsing demonstrated an improvement over conventional methods in terms of dentine penetration of a dye marker. A higher risk of apical extrusion with the RinsEndo®-system was evident. [ABSTRACT FROM AUTHOR]

Aim To evaluate the number of bacteria extruded apically from extracted teeth ex vivo after canal instrumentation using the two engine-driven techniques utilizing nickel-titanium instruments (ProTaper and System GT). Methodology Forty extracted single-rooted human mandibular premolar teeth were used. Access cavities were prepared and root canals were then contaminated with a suspension of Enterococcus faecalis and dried. The contaminated roots were divided into two experimental groups of 15 teeth each and one control group of 10 teeth. Group 1, ProTaper group: the root canals were instrumented using ProTaper instruments. Group 2, System GT group: the root canals were instrumented using System GT instruments. Group 3, control group: no instrumentation was attempted. Bacteria extruded from the apical foramen during instrumentation were collected into vials. The microbiological samples from the vials were incubated in culture media for 24 h. Colonies of bacteria were counted and the results were given as number of colony-forming units. The data obtained were analysed using the Kruskal–Wallis one-way analysis of variance and Mann–Whitney U-tests, with α = 0.05 as the level for statistical significance. Results There was no significant difference as to the number of extruded bacteria between the ProTaper and System GT engine-driven systems ( P > 0.05). Conclusions Both engine-driven nickel-titanium systems extruded bacteria through the apical foramen. [ABSTRACT FROM AUTHOR]

Abstract Aim To evaluate the weight of debris and irrigant volume extruded apically from extracted teeth in vitro after endodontic instrumentation using the balanced force technique, a hybrid hand instrumentation technique, and three engine-driven techniques utilizing nickel–titanium instruments (ProFile .04, Quantec 2000 and Pow-R). Methodology Five groups of 20 extracted human teeth with single canals were instrumented using one or other of five techniques: balanced force, hybrid, Quantec 2000, ProFile .04, or Pow-R. Debris extruded from the apical foramen during instrumentation were collected into preweighed 1.5 mL tubes. Following instrumentation, the volume of extruded irrigant fluid was determined by visual comparison to control centrifuge tubes filled with 0.25 mL increments of distilled water. The weight of dry extruded dentine debris was also established. Results Overall, the engine-driven techniques extruded less debris than the manual ones. However, there was no statistical difference between the balanced force technique and the engine-driven methods. The volume of irrigant extruded through the apex was directly associated with the weight of extruded debris, except within the ProFile group. The hybrid technique was associated with the greatest extrusion of both debris and irrigant. Conclusions Overall, the engine-driven nickel–titanium systems were associated with less apical extrusion. [ABSTRACT FROM AUTHOR]

The aim of this in vitro study was to assess the sealability of a recently introduced thermoplasticized gutta-percha technique (Trifecta, Hygenic Corp., OH, USA) in the presence or absence of a smear layer. A total of 100 teeth with single straight root canals were included in the study. The teeth were decoronated and the canals prepared with a modified double-flared technique under constant irrigation with 2.5% sodium hypochlorite solution. The apical matrix was prepared to size 40 and apical patency subsequently confirmed with a size 10 file. Four teeth were discarded for technical reasons and the remaining 96 allocated randomly into two groups of 44 teeth and a group of eight teeth which acted as controls. Canals in group 1 were obturated randomly with either cold lateral condensation of gutta-percha or with the Trifecta technique. Canals in Group 2 were rinsed with 17% REDTA to remove the smear layer and then obturated with latera, condensation or the Trifecta technique. All teeth were suspended in India ink for 9 days, demineralized, and rendered transparent prior to the assessment of apical linear dye penetration. Apical extrusion of sealer and gutta-percha occurred commonly but there was no significant difference between the four obturation groups. However, overall, there was significantly more extrusion of sealer with the Trifecta technique compared with lateral condensation (P<0.05). The majority of canals (79 out of 88) had no evidence of apical leakage and there was no significant difference between the groups. The prevalence of sealer and gutta-percha penetration into the dentinal tubules was significantly different between the four obturation techniques (P<0.01) and significantly more common in the absence of the smear layer (P<0.001). Under the conditions of this study, the Trifecta technique proved a satisfactory alternative to lateral condensation. Removal of the smear layer did not enhance sealability despite increasing the proportion of specimens with dentinal penetration of sealer and gutta-percha. [ABSTRACT FROM AUTHOR]