Comparison of two methods of irrigant agitation in the removal of residual filling material in retreatment

Analysis of the penetration of NaOCl 5.25% into dentinal tubules using different irrigation protocols: An ex vivo study

The objective of the study was to investigate the 5.25% sodium hypochlorite (NaOCl) penetration into the dentinal tubules after different irrigation methods. Seventy canines were stained with 1% crystal violet and divided into groups (n = 20): GEC-EasyClean; GPUI-E1 Irrisonic ultrasonic insert; GXP-XP-Endo finisher; GPC-conventional irrigation and GNC-stained tooth without irrigation. Axial sections (16×) were assessed and irrigant penetration was quantified as a bleaching halo on the surface of the apical, middle and coronal third. In the apical third, GPUI promoted greater NaOCl penetration (p < 0.05). GXP was better than GEC (p < 0.05), as was GPC (p > 0.05). The GPUI and GXP groups were similar in the middle and coronal third (p > 0.05). GPUI and GXP showed better results than GEC (p < 0.05). GPUI was more effective in the apical third and like GXP in the cervical and middle third.

Root canal dentin wear during final irrigation in endodontic retreatment with passive ultrasonic irrigation and easy clean instruments

Context

Complementary procedures have been proposed to improve the endodontic retreatments.

Aim

The aim of this study was to evaluate, by microcomputed tomography (micro-CT), the dentin wear caused by passive ultrasonic irrigation (PUI) and easy clean (EC) instruments, when used for the final removal of filling material during endodontic retreatment.

Methods

Thirty-six mesial roots of the lower first molars were divided into four groups (n = 9), according to the final irrigation and sealer: PUI/AH Plus, EC/AH Plus, PUI/Total Fill (TF), and EC/TF. Canal volume was evaluated, both before and after the final irrigation, by micro-CT analysis. The Kruskal-Wallis test was used to compare the volumes among groups and the paired Wilcoxon test was used to compare the volume values before and after the final irrigation within each group.

Results

Both complementary cleaning procedures promoted dentin wear that was observed only when the volume was analyzed for each third of the root canal. In the apical third, both instruments showed significant wear, where the use of the EC instrument resulted in greater wear than the PUI, in teeth filled with both AH Plus and TF BC Sealers (P < 0.05).

Conclusion

Both complementary cleaning procedures promoted dentin wear and must be used cautiously.

Effectiveness of different supplementary protocols for remaining filling material removal in endodontic reintervention: an integrative review

The aim of this study was to perform an integrative review to identify the most effective supplementary protocols used after filling material (FM) removal and root canal reinstrumentation, during endodontic reintervention. The literature search was performed on the electronic databases PubMed and Latin American and Caribbean Health Sciences Literature (LILACS), using a combination of specific scientific descriptors. Selection criteria accepted articles published in English, Spanish and Portuguese languages, up to August 2021, involving in vitro and ex vivo studies. After applying the eligibility criteria, 46 articles were included for qualitative analysis. The tool for qualitative analysis of quasi-experimental studies of the Joanna Briggs Institute was used to determine the risk of bias of the included articles. The selected articles provided important data regarding the following supplementary protocols: sonic and ultrasonic activation of the irrigating solution; the use of ultrasonic inserts, XP-endo system instruments, and photon-induced photoacoustic streaming for mechanical debridement; and new devices as GentleWave system, and the self-adjusting file. Overall, all supplementary protocols demonstrated efficacy in removing the remaining FM. The implementation of various supplementary protocols can effectively remove the remaining FM from the root canal walls, although complete removal is not always achieved. However, it was not possible to determine the most effective protocol. Conversely, their association can enhance remaining FM removal. Remaining FM attached to root canal walls hinders proper chemical-mechanical preparation during endodontic reintervention. Supplementary protocols optimize the remaining FM removal, enhancing cleaning and disinfection of root canal.

Assessment of the root surface temperature during the use of intracanal agitation systems: In vitro study

This study aimed to evaluate the temperature changes that the different methods of agitation of irrigants promote on the external dental root surface. Nine extracted human lower premolars were standardized by cone-beam computed tomography and used. The root canal was instrumented with a Reciproc 40.06 file. Temperature measurement was performed using K-type thermocouple sensors attached to the middle, cervical, and apical thirds of the teeth. The teeth had their roots immersed in distilled water at 37ºC, which were distributed into 3 experimental groups according to the mechanical agitation methods to be studied. US Group (n=3), Irrisonic Ultrasonic Tip activated through ultrasound; EC Group (n=3), Easyclean Tip coupled to a contra-angle low-speed handpiece; XP Group (n=3), XP-endo Finisher file coupled to an endodontic electrical motor. Temperature measurements were performed simultaneously with agitation and irrigation of intracanal irrigants. Statistical analysis was performed using SPSS software with a significance level of 5%. For multiple comparisons, the Tukey test was used. The association between mechanical agitation methods and root third was statistically significant. Regarding the temperatures recorded on the external surface of the roots, the ultrasonic tip was significantly higher than the XP-endo Finisher file and the Easyclean tip, which did not differ from each other. Regarding the ultrasonic tip, the external temperature in the middle third (39.46ºC) of the root was significantly lower than in the cervical (40.41ºC) and apical third (40.53ºC). None of the agitation methods of irrigants studied presented heating above 47ºC, and their use is safe for periodontal tissues.

Postoperative pain after using passive ultrasonic irrigation and EasyClean device, irrigation activation techniques: a randomized clinical trial

INTRODUCTION

This randomized clinical trial aimed to compare postoperative pain after the use of two different irrigation activation techniques, passive ultrasonic irrigation and the EasyClean device.

METHODS

Sixty-six single-rooted teeth diagnosed with asymptomatic pulp necrosis and apical periodontitis were randomly assigned to two experimental groups (n=33), which differed in the irrigation activation technique. Postoperative pain levels were assessed after 24, 48, and 72 hours using a verbal rating scale; the ibuprofen intake amount was recorded at the same time intervals. Data were analyzed using Student's t-test, Mann-Whitney U and Fisher's exact tests, with a significance level of 5%.

RESULTS

Postoperative pain levels and analgesic intake frequency were not significantly different across the two irrigation activation techniques (P > .05). The frequencies obtained in relation to the prevalence of postoperative pain were 3.1-25.8% for all participants of the two studied groups.

CONCLUSION

The irrigation activation techniques of passive ultrasonic irrigation and the EasyClean device were found to be equivalent in terms of postoperative pain and analgesic intake.

Apical extrusion of sodium hypochlorite in immature teeth: comparison of three different cleaning protocols

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.

Effectiveness of the REvision System and Sonic Irrigation in the Removal of Root Canal Filling Material from Oval Canals: An In Vitro Study

This study aimed to evaluate the effectiveness of the Endostar REvision system (Poldent, Warsaw, Poland) in the removal of filling materials from oval root canals using sonic irrigation as an additional cleaning method. Thirty human-extracted mandibular premolars with oval canals were prepared using the ProTaper Universal system (Dentsply Maillefer, Ballaigues, Switzerland) up to instrument F1 (20/.07), and then filled by the continuous wave vertical compaction technique using pulp canal sealer EWT (Sybron Dental Specialties, Orange, CA, USA). The teeth were randomly divided into two groups (n = 15) according to the instrumentation system and the additional cleaning method, as follows: REvision (30/.08, 25/.06) with EQ-S sonic activation (Meta Biomed, Chungcheongbuk-do, Korea), REvision (30/.08, 25/.06) without additional activation. All specimens were sectioned longitudinally at 3 and 7 mm from the apex, and analyzed using digital microscopy (KEYENCE, Osaka, Japan) to measure the total area of the residual obturation materials, followed by SEM analysis. The data on the percentage of remaining filling material were analyzed by Kruskal−Wallis one-way Analysis of Variance on ranks. None of the retreatment protocols completely removed the filling material from the root canals (p > 0.05); the retreatment technique using sonic activation showed statistically less residual filling materials than the retreatment technique using irrigants without activation at the coronal third (p < 0.05), whilst no significant difference was found between both tested groups at the apical and middle thirds (p > 0.05). The REvision system showed promising results in the removal of filling materials from oval canals.

Effect of irrigation protocols on root canal wall after post preparation: a micro-CT and microhardness study

The aim of this study was to investigate the effects of different post space irrigation protocols for removing residual filling material from dentin walls, by using microcomputed tomography (micro-CT), and the influence of these protocols on dentin microhardness. Bovine incisors (n = 35) were filled with the single-cone technique and MTA Fillapex (Angelus, Londrina, PR, Brazil). Post space preparation (PSP) was performed 7 days after filling, using the Odous Touch electrical system (Odous De Deus Ind. e Com., Belo Horizonte, MG, Brazil), followed by post space irrigation using manual irrigation, passive ultrasonic irrigation, or Easy Clean, together with 2.5% sodium hypochlorite (NaOCl), or with 2.5% NaOCl and 17% EDTA (NaOCl/EDTA). Micro-CT scans were performed at three time points. The residual filling material was evaluated at three levels: cervical, middle and apical. The Knoop test was measured with four indentations around the canal lumen at three dentin depths: X (100 μm), Y (200 μm) and Z (400 μm). Statistical analysis was performed using ANOVA (p < 0.05). The effects of the activation method (p < 0.001), and the root level (p = 0.013), as well as the interaction between the irrigant and the activation method (p = 0.041), led to different percentages of residual filling material. Lower amounts of residual filling material were observed at the cervical versus the middle and apical levels (p < 0.05). No significant differences were observed in dentin microhardness (p > 0.05). The best removal of the residual filling material was performed using the Easy Clean tip and NaOCl/EDTA, regardless of the activation methods.

Critical analysis of research methods and experimental models to study removal of root filling materials

Despite enjoying high favourable outcome rates, root canal treatment is not always successful. Root canal retreatment is a widely practised option for managing a non-healing root treated tooth. A basic distinction between retreatment and initial treatment is the requirement to remove the existing root filling material occupying the root canal space. Only then, can the technical deficiencies and possible causes of failure be addressed. Hence, the successful removal of the root filling material is critical to achieving the objectives of retreatment. Many different materials and techniques have been used for root canal filling, which have been documented in a plethora of studies; these are mainly laboratory studies investigating the removal of root filling materials. To help guide future research, which may then better inform clinical practice in relation to retreatment procedures, the focus of this narrative review is on the research methods and experimental models employed to study the removal of root filling materials. The current available literature demonstrates great variation in the research methodologies used to study the removal of root filling material, including direct visualization by splitting tooth samples or clearing, three-dimensional radiographic imaging including using microcomputed tomography or cone-beam computed tomography, and a combination of these techniques. Depending on the research method employed, variation also exists in quantification of root filling material removal; these include measurements of surface area, volume or weight, and criteria-based (semi-quantitative) assessment. Experimental models, using human teeth or resin models, differ with respect to standardization techniques and replication of the clinical scenario including initial sample preparation, canal filling, allocation and technical aspects of retreatment procedures. Future models should replicate, as closely as possible, the clinical scenario. Currently, microcomputed tomography provides a highly detailed, non-invasive and non-destructive method of objectively assessing and quantifying root filling removal.

The effectiveness of passive ultrasonic irrigation and the easy-clean instrument for removing remnants of filling material

Objective

This study aimed to evaluate the efficacy of passive ultrasonic irrigation (PUI) and the easy clean instrument by micro-computed tomography (CT) for removing remnant filling materials during endodontic retreatment.

Materials and Methods

Forty mesial roots of mandibular molars were divided into four groups (n = 10) according to the agitation system and sealer used: Group 1: PUI/AH Plus; Group 2: PUI/TotalFill; Group 3: Easy Clean/AH Plus; and Group 4: Easy Clean/TotalFill. The groups were compared by micro-CT analysis according to the volumes of the obturation and the remaining material before and after the agitation systems were used.

Results

There was no difference between the groups for total filling volume and initial and final remaining filling volume (P > 0.05).

Conclusions

Both the PUI and easy-clean instrument are effective for removing remnants of filling material with no difference between the groups.

Effect of Irrigating Agitation after Root End Preparation on the Wall Cleaning and Bond Strength of Calcium Silicate Material in Retrograde Obturation

Objective This study aimed to evaluate the cleaning efficacy of irrigant activation with a new ultrasonic tip in root-end preparations and to determine its influence on the bond strength of calcium silicate-based material.

Materials and Methods Maxillary canines were prepared and filled, and their root ends resected. Root-end cavities were ultrasonically prepared and randomly distributed into four groups according to the final irrigation protocols: G1 (ultrasonic irrigation [UI] + saline solution [SS]), G2 (syringe irrigation [SI] + SS), G3 (UI + ethylenediaminetetraacetic acid [EDTA]), and G4 (SI + EDTA). Cleaning efficacy analysis employed 72 specimens ( n = 18) split longitudinally for imaging of the same areas by scanning electron microscopy (SEM). The percentage of dentinal tubules opened before and after irrigation was used as evaluation parameter. Push-out testing employed 40 specimens ( n = 10) sectioned apical region perpendicularly, which slice was placed on a testing machine for the bond strength measurement and failure mode was assessed by SEM. The data were statistically analyzed (α ≤ 0.05).

Results G3 (UI + EDTA) removed the smear layer more effectively, showed the best tubule opening ( p < 0.05), and presented the highest mean bond strength values ( p < 0.05). Failure modes were predominantly adhesive, except for the G3 (UI + EDTA) group, in which they were mainly mixed (80%).

Conclusion The results of this study suggest that EDTA 17% agitation promoted better cleaning and smear layer removal, improving the push-out bond strength of calcium silicate material in retrograde obturation.

Effect of Sonic Agitation of a Binary Mixture of Solvents on Filling Remnants Removal as an Alternative to Apical Enlargement-A Micro-CT Study

BACKGROUND

This work aimed to evaluate the efficacy of sonic agitation of a binary mixture of solvents (methyl ethyl ketone/tetrachloroethylene) on filling remnants removal and compare the effects of solvent agitation with the enlargement to the next instrument size.

METHODS

Twenty-four mandibular incisors were prepared with ProTaper Next (X1, X2) and obturated with the single-cone technique and AH Plus sealer. The teeth were retreated with ProTaper Universal Retreatment and ProTaper Next and divided into two groups (n = 12) according to the final instrument (X3 or X4). All canals were submitted to a supplementary procedure consisting of a mixture of solvents-methyl ethyl ketone/tetrachloroethylene, agitated with EndoActivator. The volume of filling remnants was assessed through micro-computed tomography in the apical 5 mm. Statistical analysis was performed with a significance level of 5%.

RESULTS

The supplementary procedure of agitation of the solvent mixture was beneficial in both groups (p < 0.05). There were no statistically significant differences between canals re-prepared until X4 and canals re-prepared until X3 plus solvent (p > 0.05).

CONCLUSIONS

An additional step with a two-solvent solution potentiated by EndoActivator showed to be very effective for the removal of gutta-percha and resinous sealer remnants from apical root canals of mandibular incisors, avoiding further enlargement.

Effect of ultrasonic and Nd: Yag laser activation on irrigants on the push-out bond strength of fiber post to the root canal

OBJECTIVE

This in vitro study aimed to compare the efficacy of irrigants using various irrigation activation methods to the push-out bond strengths of fiber post to root canal luted with self-adhesive resin cement (SARC).

METHODOLOGY

Forty-eight decoronated human canines were used. The specimens were divided into four groups corresponding with the post-space irrigation process and were treated as follows: distilled water (DW) (Control) group received 15 mL of DW; sodium hypochlorite (NaOCl)+ethylenediaminetetraacetic acid (EDTA) group was treated with 5 mL of 5.25% NaOCl, 5 mL of 17% EDTA, and 5 mL of DW; passive ultrasonic irrigation (PUI) group was treated with 5 mL of 5.25% NaOCl, 5 mL of 17% EDTA, and 5 mL of DW, and each irrigant was agitated with an ultrasonic file; and laser activated irrigation (LAI) group was treated with 5 mL of 5.25% NaOCl, 5 mL of 17% EDTA, and 5 mL of DW, and each irrigant was irradiated with Nd: YAG laser. Fiber posts were luted with SARC, and a push-out test was performed. Data was analyzed using one-way analysis of variance and Tukey HSD test.

RESULTS

The bond strength values for the groups obtained were as follows: Control (10.04 MPa), NaOCl+EDTA (11.07 MPa), PUI (11.85 MPa), and LAI (11.63 MPa). No statistically significant differences were found among all experimental groups (p>0.05). The coronal (12.66 MPa) and middle (11.63 MPa) root regions indicated a significantly higher bond strength compared with the apical (9.16 MPa) region (p<0.05).

CONCLUSIONS

Irrigant activation methods did not increase the bond strength of fiber post to canal.