Histologic Assessment of Debridement of the Root Canal Isthmus of Mandibular Molars by Irrigant Activation Techniques Ex Vivo

Treatment outcomes and prognostic factors of the apical barrier technique with premixed calcium silicate-based putty in necrotic permanent teeth with open apices: a retrospective cohort study with up to six years follow-up

OBJECTIVES

To evaluate treatment outcomes of the apical barrier technique with premixed calcium silicate-based putty for treating necrotic permanent teeth with open apices and to identify prognostic factors.

MATERIALS AND METHODS

Permanent teeth with necrotic pulps and open apices treated by the apical barrier technique with premixed calcium silicate-based putty, with a minimum follow-up of 12 months, were included. Treatment outcomes were based on clinical signs, symptoms, and radiographic evaluation. The treatment outcome was dichotomized into success or failure according to strict and loose criteria. The chi-square test (or Fisher's exact test) and multiple logistic regression analysis were used to evaluate possible prognostic factors associated with treatment outcomes.

RESULTS

Seventy-four teeth with a follow-up time of 12-72 months (mean, 25.74 ± 14.36 months) were included in the final evaluation. The success rate was 97.30% using the loose criteria and 66.22% using the strict criteria. Multiple logistic regression analysis indicated that the size of pre-operative periapical lesion (≥ 5 mm) (odds ratio [OR]: 18.96; P = 0.0153) and root canal underfilling (OR: 8.341; P = 0.0448) were significant predictors for treatment failure under the strict criteria.

CONCLUSION

The apical barrier technique with premixed calcium silicate-based putty is a highly successful procedure for treating necrotic permanent teeth with open apices after an observation period of up to 6 years. Treatment success under the strict criteria is primarily affected by the size of the pre-operative periapical lesion and the apical extent of root-filling.

CLINICAL RELEVANCE

Careful case selection and ensuring adequate root filling quality are essential to the successful outcome of the apical barrier technique with premixed calcium silicate-based putty.

Evaluation of pulp tissue dissolution capacity through different sodium hypochlorite agitation protocols

Aims

This ex vivo study aimed to assess the dissolving capacity of 2.5% sodium hypochlorite using eight agitation protocols within swine pulp tissue.

Subjects and Methods

Twelve lower first premolars were prepared and split into the fragments with a groove housing porcine dental pulp. Groups were assigned based on agitation systems: manual, passive ultrasonic, Easy Clean and XP-Endo Finisher. Two agitation time protocols were applied: One min (3 s × 20 s cycles) and 2 min (6 s × 20 s cycles). Wilcoxon Mann-Whitney U test was used to compare the groups.

Results

Both time frames demonstrated superior results compared to manual group (P > 0.5). However, in the two min groups, no significant differences were observed among the other protocols (P < 0.5). Intriguingly, increasing cycle numbers significantly improved results within each group (P > 0.5).

Conclusion

Extending the chemical agitation time during final irrigation enhances tissue removal, regardless of the irrigation protocol employed.

Expert consensus on difficulty assessment of endodontic therapy

Endodontic diseases are a kind of chronic infectious oral disease. Common endodontic treatment concepts are based on the removal of inflamed or necrotic pulp tissue and the replacement by gutta-percha. However, it is very essential for endodontic treatment to debride the root canal system and prevent the root canal system from bacterial reinfection after root canal therapy (RCT). Recent research, encompassing bacterial etiology and advanced imaging techniques, contributes to our understanding of the root canal system's anatomy intricacies and the technique sensitivity of RCT. Success in RCT hinges on factors like patients, infection severity, root canal anatomy, and treatment techniques. Therefore, improving disease management is a key issue to combat endodontic diseases and cure periapical lesions. The clinical difficulty assessment system of RCT is established based on patient conditions, tooth conditions, root canal configuration, and root canal needing retreatment, and emphasizes pre-treatment risk assessment for optimal outcomes. The findings suggest that the presence of risk factors may correlate with the challenge of achieving the high standard required for RCT. These insights contribute not only to improve education but also aid practitioners in treatment planning and referral decision-making within the field of endodontics.

The efficiency of different irrigation activation techniques in the removal of calcium silicate-based endodontic sealer from artificially created groove

This study evaluated the removal of a calcium silicate-based sealer (EndoSeal MTA) with needle irrigation (NI), passive ultrasonic irrigation (PUI), XP-endo Finisher (XPF) and EDDY. A total of 56 human mandibular premolars were instrumented up to size 40.04 taper. The roots were separated longitudinally, and grooves were prepared with an ultrasonic tip at one-half of each root canal. The grooves were covered with EndoSeal MTA and re-attached roots were investigated based on the activation techniques applied. The results showed that significantly more material (p < 0.05) was removed in the EDDY group compared to the NI, PUI and XPF groups in the apical region. In the coronal region, no significant difference was observed between EDDY, XPF and PUI (p > 0.05), whereas all the latter were significantly more effective than NI (p < 0.05). These findings show that the removal of EndoSeal MTA can be more effective with EDDY compared to XPF, PUI and NI in the apical region.

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

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

Histological evaluation of the debris removal efficiency of activation of sodium hypochlorite solution at different concentrations

BACKGROUND

This study aims to histologically evaluate the efficiency of debris removal through activation of 2.5% and 5.25% NaOCI using laser, ultrasonic, and intracanal heating methods.

METHODS

Sixty-four maxillary central incisor teeth were randomly divided into two groups according to the irrigation solution (n = 32); 2.5% NaOCI and 5.25% NaOCI. Subsequently, the samples were further divided into four subgroups according to the final irrigation activation technique (n = 8); SubgroupA: Er,Cs:YSGG laser, SubgroupB: Ultrasonic, Subgroup C: Intracanal heating, Subgroup D: no activation. Generalized Linear Models and Bonferroni tests were used for statistical analysis (p < 0.05).

RESULTS

The effect of NaOCI concentration was statistically significant (p < 0.001). Furthermore, the activation of NaOCI by laser exhibited a statistically significant difference compared to the ultrasonic and intracanal heating methods (p < 0.001).

CONCLUSION

The efficiency of root canal cleaning increases with higher NaOCI concentration. Activation of NaOCI also significantly enhances its effectiveness.

Isthmus morphology influences debridement efficacy of activated irrigation: A laboratory study involving biofilm mimicking hydrogel removal and high-speed imaging

AIM

Little is known about the influence of isthmus morphology on the debridement efficacy of activated irrigation. The aim of this study was to investigate the influence of isthmus morphology on the debridement efficacy of laser-activated irrigation (LAI), EDDY and needle irrigation (NI), and to explain the methods of isthmus cleaning by LAI and EDDY.

METHODOLOGY

Four root canal models (apical diameter: 0.30 mm, taper: 0.06, curvature: 23°, length: 20 mm) were produced by CAD-CAM with different isthmus morphologies: long-wide (4 mm; 0.4 mm), long-narrow (4 mm; 0.15 mm), short-wide (2 mm; 0.4 mm) and short-narrow (2 mm; 0.15 mm). The isthmuses were filled with a hydrogel containing dentine debris. The canals were filled with irrigant and models were assigned to the following irrigation protocols (n = 240): needle irrigation (NI) with a 30G needle, Eddy, and LAI (2940 nm Er:YAG-laser, 15 Hz, 40 mJ, SWEEPS, tip at the canal entrance). Standardized images of the isthmuses were taken before and after irrigation, and the amount of removed hydrogel was determined using image analysis software and compared across groups using Kruskal-Wallis test followed by Dunn's multiple comparison. Visualization of the isthmus during activation was achieved using a high-speed camera. The pattern and speed of the flow in the isthmus as well as transient and stable cavitation were analysed using imaging software.

RESULTS

Laser-activated irrigation, EDDY and NI removed more hydrogel in short-wide isthmuses than in narrow isthmuses (p < .001). LAI and EDDY removed more hydrogel than NI in every isthmus configuration (p < .001). EDDY showed eddies and stable cavitation, and LAI showed transient cavitation at each pulse, and pulsed horizontal flow with the highest particle speed in closed short isthmuses.

CONCLUSIONS

Isthmus morphology influences debridement in all irrigation groups. Short-wide isthmuses were the easiest to clean while narrow isthmuses were the most challenging to clean. Width seems to be a more critical anatomical parameter than length. LAI and EDDY resulted in the greatest biofilm removal and performed better than NI. EDDY produced eddies and stable cavitation in the isthmus, and LAI showed transient cavitation and pulsed horizontal flow.

Comparative evaluation of efficacy of different irrigation devices in removal of calcium hydroxide in teeth with simulated internal resorption cavities - An in vitro study

Aim

The aim of this in vitro study was to compare the efficacy of newly developed irrigation systems, i.e., XP-endo Finisher file (XP-endo), EndoActivator (EA), and Endo-Irrigator Plus (EI) with gold standard passive ultrasonic irrigation (PUI) tip and in removal of calcium hydroxide (CH) from single-rooted teeth with artificial simulated internal resorption cavities.

Materials and Methods

One hundred and twenty single-rooted mandibular premolars were decoronated and prepared using the ProTaper Gold system up to F5. Samples were buccolingually sectioned and resorption cavities were prepared. Twenty specimens were served as Group 1 - negative control. In the remaining specimens, CH was delivered and root halves were brought together. Twenty specimens were served as Group 2 - positive control. The remaining specimens were randomly divided into four experimental groups (n = 20), where NaOCl and EDTA were activated using PUI, XP-endo, EA, and EI for 1 min. The remnants of CH were scored and analyzed by employing Kruskal-Wallis H- and Mann-Whitney U-tests.

Results

PUI and XP-endo removed more CH than other devices (P < 0.05), showing no significant difference between them.

Conclusion

None of the tested systems were able to remove CH completely from resorption cavities. PUI and XP-endo were superior to other tested devices.

Irrigant flow characteristics in the root canal with internal root resorption: a computational fluid dynamics evaluation

Irrigation dynamics of syringe irrigation with different needle designs (side-vented, double side-vented, notched) and ultrasonic irrigation in the root canal with internal root resorption were evaluated using a computational fluid dynamics model. A micro-CT scanned mandibular premolar was used for modeling internal root resorption. The needles and the ultrasonic tip were positioned at 2, 4, and 5 mm from the working length. The insertion depth and the irrigation model were found influential on the shear stress and the irrigant extension. The extension of the irrigant increased toward 2-5 mm from the working length. Ultrasonic irrigation revealed the highest shear stress values regardless of the insertion depth. The shear stress distribution on the resorption cavity walls gradually increased when the needles were positioned coronally. The residence time of the irrigant in the canal was affected by the needle position relative to the internal root resorption cavity and the needle type.

Presence of voids after three obturation techniques in band-shaped isthmuses: a micro-computed tomography study

Background

The objective of the present micro-computed tomography (micro-CT) study was to assess the presence of voids in band-shaped isthmuses obturated using three different filling techniques.

Methods

Twenty-four artificial molar teeth with a band-shaped isthmus were allocated to three groups (n = 8) for obturation, according to the filling technique: single-cone (SC), continuous wave of condensation (CWC) or lateral condensation (LC). Obturation was performed with gutta-percha (GP) cones and iRoot SP (Innovative Bioceramix, Vancouver, Canada). Post-filling micro-CT scanning was performed. The percentage of filling materials and void volumes were calculated in the isthmus areas and data were analyzed using one-way ANOVA and Tukey tests.

Results

The mean percentage of void volumes and corresponding filling percentages in the isthmus areas after obturation in the SC groups was 22.98 % ± 1.19 %, 77.02 % ± 1.19 %; in the CWC groups 10.46 % ± 2.28 %, 89.54 % ± 2.28 %; and in the LC groups was 13.14 % ± 1.85 %, 86.86 % ± 1.85 %, respectively.

Conclusions

In band-shaped isthmus area, the obturation quality of CWC was superior to SC and LC techniques.

Effect of different final irrigation protocols on pulp tissue dissolution from an isthmus model

This study assessed the pulp tissue dissolution from isthmus of a two-rooted maxillary premolar using different final irrigation protocols. After root canal preparation, the surface of the tooth was reduced to an extent that the isthmus could be observed, and 1 mg of pulp tissue was introduced into the isthmus which was covered with a glass slide. Following six groups were tested: syringe and needle; subsonic activation; sonic activation; ultrasonic activation; heating followed by sonic activation; and heating followed by ultrasonic activation. Before and after each experiment a photograph of the isthmus was taken at 30× to register the area of the pulp tissue. Statistical analysis was performed with Kruskal-Wallis and Mann-Whitney tests (P < 0.05). Syringe and needle group showed the lower value of pulp tissue dissolution followed by subsonic irrigation procedures. Pulp tissue dissolution was significantly higher when heating was followed by sonic or ultrasonic activation.

Root canal debridement efficacy of heated sodium hypochlorite in conjunction with passive ultrasonic agitation: An ex vivo study

Background. This study aimed to investigate the endodontic debridement efficacy of different sodium hypochlorite (NaOCl) irrigation regimens with and without ultrasonic agitation, followed by ethylenediaminetetraacetic acid (EDTA) via scanning electron microscopy (SEM) after using a rotary instrumentation system.

Methods. Mandibular premolars (n=50) were randomly divided into five experimental groups (n=10) for root canal instrumentation with ProTaper Universal rotary system up to F3. The root canal system was treated with intracanal-heated NaOCl (100°C) or preheated NaOCl (55°C), followed by ultrasonic agitation and EDTA treatment. Samples irrigated with conventional needle irrigation (CNI) using normal saline solution were used as controls. Debridement efficacy was analyzed by SEM. A five-point scale was used to estimate the presence/absence of debris for each canal segment (coronal, middle, and apical). The results were analyzed using one-way ANOVA and post hoc Tukey tests (P<0.05).

Results. The experimental groups exhibited less debris compared to CNI with saline (P<0.05). The amount of debris decreased significantly for the group with NaOCl intracanal heating compared to extraoral heating. Ultrasonic agitation further enhanced the root canal debridement efficacy of NaOCl.

Conclusion. In summary, intracanal heating of NaOCl with and without ultrasonic agitation followed by EDTA appears to be a promising method to flush debris from the root canal system.

Clinical efficacy of activated irrigation in endodontics: a focused review

Root canal debridement, which includes the removal of infected tissues and microbial biofilms, is considered the corner stone of root canal treatment. Chemical adjuncts play a multitude of functions in this regard, as tissue solvents, antimicrobial agents and for removing the smear layer. These adjuncts (irrigants) are usually delivered using a syringe and needle. With increasing knowledge of the complexity of root canal anatomy and tenacity of microbial biofilms, the need for strategies that potentiate the action of these irrigants within the root canal system cannot be overemphasized. Several such activated irrigation strategies exist. The aim of this review is to comprehensively discuss the different irrigant activation methods from the context of clinical studies.

A laboratory study of root canal and isthmus disinfection in extracted teeth using various activation methods with a mixture of sodium hypochlorite and etidronic acid

AIM

To evaluate in a laboratory setting the antibiofilm activity of several irrigating protocols including conventional irrigation, ultrasonic activation and XP-endo Finisher, with a mixture of sodium hypochlorite and etidronic acid in infected isthmuses and root canals of extracted human mandibular molar teeth.

METHODOLOGY

Fifty-six mesial roots of mandibular molars, half of them with a continuous isthmus from the cervical to the apical third between the two root canals (type 1), and the other half with a continuous isthmus from the cervical to the middle third and one canal in the apical third (type 2), were included. The root canals were contaminated for 7 days with an Enterococcus faecalis suspension. There were three experimental groups plus a control group (n = 7 per type of root canal anatomy). All the root canals, except for the control group that was not treated, were chemomechanically prepared and then assigned to one of the experimental groups according to the final adjunctive procedure: conventional irrigation, ultrasonic activation or XP-endo Finisher activation. The irrigating solution used was a combination of 2.5% sodium hypochlorite and 9% etidronic acid, and the final protocols were applied for three cycles of 30 s with a 3 mL volume. The antibiofilm activity was evaluated at each location (root canal and isthmus) and third (cervical, middle and apical) using confocal laser scanning microscopy and the live/dead technique. Statistical analysis was performed using SPSS (descriptive statistics) and SUDAAN (P-value calculations).

RESULTS

Root canals had significantly lower biovolume values than the isthmuses (P < 0.05). The biovolume in the root canals was significantly reduced in all the experimental groups in all the thirds except for conventional irrigation in the apical third (P > 0.05). In the cervical and middle thirds, ultrasonic activation was associated with the lowest biovolumes (P < 0.05), followed by XP-endo Finisher. In the isthmus, disinfection was similar in all the thirds for all the protocols. Conventional irrigation was associated with intermediate values with no significant differences from the control group or from the activated protocols (P > 0.05), although the latter were significantly different from the control group (P < 0.05). No differences were found between ultrasonic activation and XP-endo Finisher in the middle and apical thirds (P > 0.05) in the isthmuses.

CONCLUSIONS

In this laboratory study on extracted teeth, the isthmus was more difficult to disinfect than root canals. In the root canals, ultrasonic activation and XP-endo Finisher had a greater effectiveness than conventional irrigation. In the isthmuses, no differences were observed between the two activation techniques and conventional irrigation.

Debris extrusion during root canal preparation with nickel-titanium instruments using liquid and gel formulations of sodium hypochlorite in vitro

This study compared the amount of apically extruded debris during root canal preparation with three single-file systems using liquid and gel-based formulations of sodium hypochlorite (NaOCl) or distilled water. Seventy-two single-canalled roots were divided into three groups: HyFlex EDM (Coltene-Whaledent); Reciproc Blue (VDW); and F-One Blue (Shanghai Fanta) and then divided into three subgroups: NaOCl liquid (Imicrly), NaOCl gel (Cerkamed Medical) and distilled water. The amount of extruded debris was calculated by determining the dry weight of the debris collected. Data were analysed using Kruskal-Wallis test with Bonferroni correction. Debris extrusion occurred in all subgroups. Both the instrument and the irrigant had an impact. The F-One Blue tended to extrude the least debris, though no significant difference was observed in the pairwise comparisons between instruments. NaOCl liquid resulted in significantly more extruded debris than NaOCl gel or distilled water. The results lead us to conclude that the NaOCl gel reduced debris extrusion compared to NaOCl liquid.

Measurement of Simulated Debris Removal Rates in an Artificial Root Canal to Optimize Laser-Activated Irrigation Parameters

BACKGROUND AND OBJECTIVES

To compare temporal rates of debris removal from an artificial root canal for three laser-assisted irrigation modalities single-pulse super short pulse (SSP), and two dual-pulse X-SWEEPS and AutoSWEEPS, and for two fiber-tip (FT) geometries flat and radial, and to evaluate the dependence of the debris flushing rate on the delay between the SWEEPS laser pulse pair.

STUDY DESIGN/MATERIALS AND METHODS

Laser-assisted irrigation was performed with a pulsed Er:YAG laser operating in single-pulse SSP and dual-pulse SWEEPS laser modalities. The laser energy was delivered to the water-filled model access cavity through a FT with either a flat or radial ending. The X-SWEEPS modality delivered pairs of laser pulses separated by a fixed adjustable delay, while with the AutoSWEEPS modality the delay was automatically and repeatedly swept between 200 and 600 microseconds. The debris removal rate was determined with the use of a digital camera by measuring the rate at which a simulated debris was being flushed out of the artificial root canal.

RESULTS

The simulated debris removal rate of the AutoSWEEPS modality is almost three times higher compared with that of the SSP modality. Further, the flat FT outperforms the radial FT by a factor of more than five in the case of SSP, and by more than 10 with AutoSWEEPS. The X-SWEEPS flushing rate exhibits strong dependence on the delay between the SWEEPS pulse pair, with the highest removal rate measured to be more than seven times higher in comparison with SSP.

CONCLUSION

Dual-pulse laser irrigation modalities (AutoSWEEPS and X-SWEEPS) exhibit significantly higher simulated debris removal rates in comparison with the standard single-pulse SSP laser-assisted irrigation. As opposed to the previously reported dependence of pressure generation on FT geometry, the flat FT's simulated debris removal rate significantly outperforms the radial FT. © 2020 The Authors. Lasers in Surgery and Medicine published by Wiley Periodicals LLC.

Ultrasonic Irrigant Activation during Root Canal Treatment: A Systematic Review

INTRODUCTION

The aim of this study was to systematically review the evidence on the cleaning and disinfection of root canals and the healing of apical periodontitis when ultrasonic irrigant activation is applied during primary root canal treatment of mature permanent teeth compared with syringe irrigation.

METHODS

An electronic search was conducted of the Cochrane Library, Embase, LILACS, PubMed, SciELO, and Scopus databases using both free-text key words and controlled vocabulary. Additional studies were sought through hand searching of endodontic journals and textbooks. The retrieved studies were screened by 2 reviewers according to predefined criteria. The included studies were critically appraised, and the extracted data were arranged in tables.

RESULTS

The electronic and hand search retrieved 1966 titles. Three clinical studies and 45 in vitro studies were included in this review. Ultrasonic activation did not improve the healing rate of apical periodontitis compared with syringe irrigation after primary root canal treatment of teeth with a single root canal. Conflicting results were reported by the in vitro microbiological studies. Ultrasonic activation was more effective than syringe irrigation in the removal of pulp tissue remnants and hard tissue debris based on both clinical and in vitro studies. Ultrasonic activation groups were possibly favored in 13 studies, whereas syringe irrigation groups may have been favored in 3 studies.

CONCLUSIONS

The level of the available evidence was low, so no strong clinical recommendations could be formulated. Future studies should focus on the antimicrobial effect and healing of apical periodontitis in teeth with multiple root canals.

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

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

Effectiveness of supplementary irrigant agitation with the Finisher GF Brush on the debridement of oval root canals instrumented with the Gentlefile or nickel titanium rotary instruments

AIM

To examine the efficacy of a novel supplementary irrigant agitating brush (Finisher GF Brush, MedicNRG, Kibbutz Afikim, Israel) on the debridement of root canals prepared with a novel stainless steel rotary instrumentation system (Gentlefile; MedicNRG), or nickel titanium rotary instruments in oval root canals.

METHODOLOGY

Mandibular premolars (n = 72) were selected and divided randomly into three experimental groups (n = 24) after microCT scanning: group 1, canal preparation to rotary NiTi size 20, .04 taper (R20); group 2, rotary NiTi to size 25, .04 taper (R25) and group 3, Gentlefile size 23, .04 taper (GF). Specimens were subdivided into two subgroups: subgroup A, syringe-and-needle irrigation (SNI); subgroup B, Finisher GF Brush (GB). Ten untreated canals served as controls. Specimens were processed for histological evaluation, and the remaining pulp tissue (RPT) was measured. Data were analysed using Mann-Whitney and Kruskal-Wallis tests (P = 0.05).

RESULTS

All experimental groups had significantly less RPT than the control (P < 0.05). Group 3B (GF-GB) had significantly less RPT than groups 1B (R20-GB) and 2B (R25-GF; P < 0.05). When irrigated with SNI, there was no significant difference in the RPT between the three groups (P > 0.05). When instrumented with R20, there was no significant difference between SNI and GF (P < 0.05) whilst GB had significantly less RPT than SNI for R25 (P < 0.05).

CONCLUSIONS

Supplementary irrigant agitation with the Finisher GF Brush improved the debridement of canals prepared with Gentlefile and size 25, .04 taper rotary NiTi. Root canal debridement did not significantly differ between the instruments when syringe irrigation was used.

Comparative evaluation of the amount of debris extruded apically using conventional syringe, passive ultrasonic irrigation and EndoIrrigator Plus system: An in vitro study

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.

Biofilms in Endodontics-Current Status and Future Directions

Microbiota are found in highly organized and complex entities, known as biofilms, the characteristics of which are fundamentally different from microbes in planktonic suspensions. Root canal infections are biofilm mediated. The complexity and variability of the root canal system, together with the multi-species nature of biofilms, make disinfection of this system extremely challenging. Microbial persistence appears to be the most important factor for failure of root canal treatment and this could further have an impact on pain and quality of life. Biofilm removal is accomplished by a chemo-mechanical process, using specific instruments and disinfecting chemicals in the form of irrigants and/or intracanal medicaments. Endodontic research has focused on the characterization of root canal biofilms and the clinical methods to disrupt the biofilms in addition to achieving microbial killing. In this narrative review, we discuss the role of microbial biofilms in endodontics and review the literature on the role of root canal disinfectants and disinfectant-activating methods on biofilm removal.

Apical negative pressure irrigation versus syringe irrigation: a systematic review of cleaning and disinfection of the root canal system

The aim of this study was to systematically 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. An electronic search was conducted in EMBASE, LILACS, PubMed, SciELO, Scopus and Web of Knowledge using both free-text keywords and controlled vocabulary. Additional studies were sought through hand searching of endodontic journals and of the relevant chapters of endodontic textbooks. No language restriction was imposed. The retrieved studies were screened by two reviewers according to predefined criteria. Included studies were critically appraised and the extracted data were arranged in tables. The electronic search and hand search retrieved 489 titles. One clinical study and 14 in vitro studies were finally included in the review; none of these studies assessed treatment outcome, four studies assessed the antimicrobial effect, seven studies evaluated the removal of pulp tissue remnants, and four studies investigated the removal of hard tissue debris or both hard tissue debris and pulp tissue remnants. Poor standardization and description of the protocols was evident. Inconclusive results were reported about the cleaning and disinfection accomplished by the two irrigation methods. Negative pressure irrigation was more effective under certain conditions when compared to suboptimal syringe irrigation; however, the variability of the protocols hindered quantitative synthesis. There is insufficient evidence to claim general superiority of any one of these methods. The level of the available evidence is low, and the conclusions should be interpreted with caution.