Comparison of two negative pressure systems and syringe irrigation for root canal irrigation: anex vivostudy

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.

Evaluation of irrigant extrusion following the use of different root canal irrigation techniques: A systematic review and meta-analysis

This systematic review investigates whether different irrigation techniques have different effects on irrigant extrusion from mature tooth apices. Articles published between January 2000 and January 2022 were searched in six electronic databases (MEDLINE, Embase, Google Scholar, Web of Science, Scopus and Cochrane) using appropriate keywords. Overall, 2265 articles were screened by their titles and abstracts. Fifty-six full-text articles were selected based on the inclusion criteria. Of them, 17 in vitro studies were included in the systematic review and meta-analysis. The meta-analysis was conducted using the random-effects inverse variance method. The results showed that the negative pressure technique caused a lesser amount (p = 0.00) and frequency (p = 0.00) of extrusion than the open-ended needle irrigation. Sonic and ultrasonic activation caused less amount of extrusion than both open-ended (p = 0.00 or p = 0.01) and closed-ended needle (p = 0.00) irrigation.

Comparative Study Assessing the Canal Cleanliness Using Automated Device and Conventional Syringe Needle for Root Canal Irrigation-An Ex-Vivo Study

The success of endodontic treatment relies on both apical and coronal sealing. To achieve a good three-dimensional seal, the removal of the smear layer becomes mandatory. This study aims to assess the difference in debris accumulation and smear layer formation while using automated root canal irrigation and conventional syringe needle irrigation. Single-rooted human mandibular premolar teeth (n = 30) which were indicated for orthodontic extractions were selected. An endodontic access cavity was prepared, and a glide path was created. Based on the irrigation protocol decided upon for the study, the teeth were randomly allocated into three study groups, namely Group 1, where the manual syringe needle irrigation method was adopted; Group 2, in which automated root canal irrigation was undertaken; and Group 3, in which teeth remained un-instrumented as it was considered the Control group. The teeth were decoronated at the cement-enamel junction (CEJ) and were subjected for scanning electron microscopy (SEM) examination. Debris and smear layers were viewed in 1000× magnification and scored. A statistically significant (p < 0.05) lower mean debris and smear layer score (p < 0.05) was observed in both study groups when compared with the control group. However, no significant difference (p > 0.05) in the debris and smear layer was observed between the manual syringe needle irrigation and automated irrigation, although automated irrigation devices can be a potential alternative. The present study concluded that the efficacy of smear layer removal remained the same with both automated irrigation and manual syringe irrigation.

A critical analysis of research methods and experimental models to study irrigants and irrigation systems

Irrigation plays an essential role in root canal treatment. The purpose of this narrative review was to critically appraise the experimental methods and models used to study irrigants and irrigation systems and to provide directions for future research. Studies on the antimicrobial effect of irrigants should use mature multispecies biofilms grown on dentine or inside root canals and should combine at least two complementary evaluation methods. Dissolution of pulp tissue remnants should be examined in the presence of dentine and, preferably, inside human root canals. Micro-computed tomography is currently the method of choice for the assessment of accumulated dentine debris and their removal. A combination of experiments in transparent root canals and numerical modeling is needed to address irrigant penetration. Finally, models to evaluate irrigant extrusion through the apical foramen should simulate the periapical tissues and provide quantitative data on the amount of extruded irrigant. Mimicking the in vivo conditions as close as possible and standardization of the specimens and experimental protocols are universal requirements irrespective of the surrogate endpoint studied. Obsolete and unrealistic models must be abandoned in favour of more appropriate and valid ones that have more direct application and translation to clinical Endodontics.

Present status and future directions - irrigants and irrigation methods

Irrigation is considered the primary means of cleaning and disinfection of the root canal system. The purpose of this review was to set the framework for the obstacles that irrigation needs to overcome, to critically appraise currently used irrigants and irrigation methods, to highlight knowledge gaps and methodological limitations in the available studies and to provide directions for future developments. Organization of bacteria in biofilms located in anatomic intricacies of the root canal system and the difficulty to eliminate them is the main challenge for irrigants. Sodium hypochlorite remains the primary irrigant of choice, but it needs to be supplemented by a chelator. Delivery of the irrigants using a syringe and needle and activation by an ultrasonic file are the most popular irrigation methods. There is no evidence that any adjunct irrigation method, including ultrasonic activation, can improve the long‐term outcome of root canal treatment beyond what can be achieved by instrumentation and syringe irrigation. It is necessary to redefine the research priorities in this field and investigate in greater depth the penetration of the irrigants, their effect on the biofilm and the long‐term treatment outcome. New studies must also focus on clinically relevant comparisons, avoid methodological flaws and have sufficiently large sample sizes to reach reliable conclusions. Future multidisciplinary efforts combining the knowledge from basic sciences such as Chemistry, Microbiology and Fluid Dynamics may lead to more effective antimicrobials and improved activation methods to bring them closer to the residual biofilm in the root canal system.

Efficacy of Different Endodontic Irrigant Activation Systems on Smear Layer Removal and Canal Cleanliness: Comparative Scanning Electron Microscopic Study

AIM: This study assessed the effectiveness of 5 different irrigant activation systems on canal cleanliness and removal of smear layer from root canals. METHODS: A total of 110 mandibular premolars with straight root canal were assigned to five groups (n = 20): conventional needle irrigation, passive ultrasonic activation, sonic activation with EndoActivator, negative apical pressure EndoVac (EV), or EDDY system, besides a control group (n = 10). All teeth were prepared to size 40, and irrigated with NaOCl (5.25%) according to the respective technique. Roots were split longitudinally and subjected to scanning electron microscopic analysis. The presence of smear layer and debris was evaluated using 5-grade scoring systems with ×1000 and ×400 magnification, respectively. Data were analyzed at 5%. RESULTS: Regarding the smear layer, activation with EV and ED was significantly more effective than other activation groups (p < 0.05). Activation of the irrigant significantly improved removal of debris (p < 0.05). CONCLUSION: No activation technique was able to eliminate smear layer and debris completely from root canals, nevertheless, EDDY is significantly better in removing debris and smear layer from the apical third of the canal.

Removal of the root canal smear layer using Carisolv III and sodium hypochlorite

The present study investigated the effectiveness of a Carisolv III + 0.5% sodium hypochlorite (NaOCl)-based root canal irrigant for smear layer removal.Forty maxillary incisors were randomly divided into 4 groups (n = 10 per group). The canals in group A (experimental) were prepared with 0.5% NaOCl, and Carisolv III and 0.5% NaOCl was used for the final washing; groups B and C (positive controls) used 2% and 5.25% NaOCl, respectively; and group D (negative control) used phosphate-buffered saline (PBS). Ethylenediaminetetraacetic acid (EDTA) was used for all of the groups. A 5-point scoring scale and scanning electron microscopy were used to evaluate the effectiveness of the irrigants. The canals were consistently cleaner in the coronal and middle thirds than in the apical thirds (P < .05).For cleaning the root canals, 5.25% NaOCl was more effective than 2% NaOCl, 0.5% NaOCl + Carisolv III, and phosphate-buffered saline , respectively (P < .05). The 2% NaOCl solution showed similar results to 0.5% NaOCl + Carisolv III (P > .05). The combination of 5.25% NaOCl and 17% EDTA remains the most effective irrigant for removal of the root canal smear layer.A combination of Carisolv III + 0.5% NaOCl (with 17% EDTA) showed a cleaning ability similar to that of 2% NaOCl (with 17% EDTA).

Comparison of the Volume of Root Canal Irrigant Collected by 2 Negative Pressure Needles at Different Flow Rates of Delivery

INTRODUCTION

A greater irrigant volume improves the effectiveness of root canal irrigation. The purpose of this study was to compare 2 negative pressure systems regarding the volume of irrigant collected from the apical area in moderately curved canals at 3 different flow rates of delivery in vitro.

METHODS

The mesiobuccal canals of 30 molars with a curvature between 20° and 40° were prepared to size #40.04 taper. A closed system was created. The canals were irrigated at 3, 6, and 12 mL/min for 30 seconds using EndoVac (SybronEndo, Orange, CA) and the INP needle (Mixnus Fine Engineering Co Ltd, Nagano, Japan) (both independent variables). A recovery trap was used to collect the irrigant aspirated by the negative pressure needles. Irrigant volume (dependent variable) was measured in milliliters. Data were analyzed using mixed analysis of variance.

RESULTS

There was a statistically significant interaction between the negative pressure system and the irrigant volume collected (P < .0005). The mean irrigant volume collected by the different negative pressure systems was greater for INP at 3 (P < .001), 6 (P < .001), and 12 mL/min (P < .001) flow rate. Both negative pressure needles showed statistically significant differences (P < .001) between mean irrigant volume collected at different flow rates.

CONCLUSIONS

A greater volume was collected by increasing the flow rate of irrigant delivery for both EndoVac and INP. The INP needle could collect a greater volume of irrigant from the apical third compared with EndoVac at all 3 different flow rates.

Apical Negative Pressure irrigation presents tissue compatibility in immature teeth

Aim:

To compare the apical negative pressure irrigation (ANP) with conventional irrigation in the teeth of immature dogs with apical periodontitis.

Methods:

Fifty-two immature pre-molar root canals were randomly assigned into 4 groups: ANP (n=15); conventional irrigation (n=17); healthy teeth (control) (n = 10); and teeth with untreated apical periodontitis (control) (n=10). After induction of apical periodontitis, teeth were instrumented using EndoVac^® (apical negative pressure irrigation) or conventional irrigation. The animals were euthanized after 90 days. The sections were stained by HE and analyzed under conventional and fluorescence microscopy. TRAP histoenzymology was also performed. Statistical analyses were performed with the significance level set at 5%.

Results:

There was difference in the histopathological parameters between ANP and conventional groups (p<0.05). The ANP group showed a predominance of low magnitude inflammatory infiltrate, a smaller periodontal ligament, and lower mineralized tissue resorption. There were no differences in the periapical lesion extensions between the ANP and conventional groups (p>0.05). However, a lower number of osteoclasts was observed in the ANP group (p<0.05).

Conclusion:

The EndoVac^® irrigation system presented better biological results and more advanced repair process in immature teeth with apical periodontitis than the conventional irrigation system, confirming the hypothesis.

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.