Do smear-layer removal agents affect the push-out bond strength of calcium silicate-based endodontic sealers?

Influence of initial root canal treatment on intratubular penetrability and bond strength of nonsurgical retreatment: an in vitro study

AIM

To assess the effect of combinations of two different endodontic sealers used in initial and endodontic retreatment on the bond strength of the secondary obturation and the penetrability of the sealers.

METHODS

Forty-eight mandibular premolars were used, receiving standardized endodontic access and biomechanical preparation. Twenty-four teeth received AH Plus sealer (AHP) in primary obturation, and the others received Bio-C® Sealer (BCS) sealer. Retreatment protocol was performed with an R50 instrument. The samples were further subdivided into four groups (n=12) based on the combination of primary/secondary obturation sealers: AHP/AHP; AHP/BCS; BCS/AHP; BCS/BCS. Four samples from each subgroup received the addition of fluorophores to the sealer for penetrability analysis using laser scanning confocal fluorescence microscopy (LSCFM). The root portion on the 8 push-out samples was sectioned into 6 slices of 1.0 mm. Bond strength (BS) was assessed using a universal testing machine until displacement of the filling mass. Failure pattern was evaluated under a stereomicroscope (20x magnification). BS data were analyzed using two-way ANOVA followed by Tukey's test (p<0.05), and the association between the failure pattern and BS value was assessed using the chi-square test (p<0.05). Penetrability was qualitatively evaluated.

RESULTS

The highest BS values were observed in the AHP/AHP (4.54±1.5 MPa) and BCS/AHP (5.00±1.0 MPa) groups (p<0.05), with a higher percentage of adhesive failures to the filling material for all groups. LSCFM images indicated greater penetrability of AHP compared to BCS, both in initial treatment and retreatment.

CONCLUSION

AHP sealer exhibited higher BS and greater penetrability compared to BCS sealer.

Does the Mixing Method of AH Plus Jet Affect its Physicochemical and Mechanical Properties?

INTRODUCTION

The purpose of this study was to evaluate whether the mixing method of AH Plus Jet sealer affects its physicochemical and mechanical properties.

METHODS

The properties of AH Plus Jet sealer were analyzed when mixed using either the Auto Mix Tip or manual mixing. The evaluated properties included radiopacity (n = 5), initial and final setting times (n = 5), flow (n = 5), and solubility (n = 3), following specifications outlined in ISO 6876/2012 and ADA Nº 57/2000. pH levels were measured at intervals of 3, 24, 72, and 168 hours (n = 10). The push-out bond strength test was conducted using a universal testing machine and using bovine teeth (n = 30). Failure modes were analyzed with stereomicroscopy. Porosity was evaluated under micro-CT (n = 5), and scanning electron microscopy was also performed (n = 5). One-way analysis of variance and Tukey, unpaired t-tests, or Mann-Whitney tests were used with a significance level of 5%.

RESULTS

The Auto Mix exhibited a radiopacity value of 12.11 mmAl, whereas manual mixing resulted in 12.55 mmAl (P > .05). For initial and final setting times, Auto Mix showed 901 minutes and 1779 minutes, respectively, while manual mixing recorded values of 631 minutes and 1504 minutes (P < .05). In terms of flow, Auto Mix demonstrated higher values (25.26 mm) than manual mixing (21.71 mm) (P < .05). No statistical differences were observed between the two methods for solubility and pH (P > .05). Manual mixing presented a higher bond strength value (14.52 MPa) than Auto Mix (9.81 MPa) (P < .05). The mixed failure mode was the most frequent outcome for both methods. The highest porosity was observed for Auto Mix (P < .05). Scanning electron microscopy analysis revealed that manual mixing resulted in a smoother surface with fewer pores and smaller, more evenly distributed agglomerates compared to automatic mixing.

CONCLUSION

The mixing method employed for AH Plus Jet sealer influences some physicochemical and mechanical properties of the material.

Effects of ethylenediaminetetraacetic acid, citric acid, and etidronic acid on root dentin mineral content and bond strength of a bioceramic-based sealer: A scanning electron microscopy-energy dispersive spectroscopy study

Background

This study assessed the impact of chelating agents, 17% ethylenediaminetetraacetic acid (EDTA), 10% citric acid (CA), and 18% etidronic acid (HEDP), on root dentin mineral content. Scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) was applied to analyze changes, and the push-out bond strength test was used to measure dentin adhesion of Well-Root ST, a bioceramic root canal sealer.

Methods

A total of 80 extracted single-rooted lower premolar teeth were included in this study and randomly divided into four groups (n=20): group 1 (17% EDTA), group 2 (10% CA), group 3 (18% HEDP), and group 4 (distilled water, control). After irrigation and drying, SEM-EDS was applied to analyze eight samples from each group at coronal, middle, and apical root regions for mineral content and SEM images. The remaining 12 samples underwent a push-out bond strength test using Well-Root ST sealer and gutta-percha. Kruskal-Wallis and Dunn's tests were used for statistical analyses.

Results

Statistically significant differences were found between groups (P<0.05). SEM-EDS showed significant differences in C, O, Ca, P, and Ca/P content, with no significant differences in Na and Mg. Push-out bond strength was significantly higher in the 17% EDTA, 10% CA, and 18% HEDP groups compared to the control group, with no significant differences between chelating agents.

Conclusion

Chelating agents altered root dentin mineral content and improved the adhesive properties of the bioceramic sealer. These findings highlight the importance of considering the selection and use of chelating agents in the clinical practice for root canal treatment.

Physicochemical properties of calcium silicate cement based endodontic sealers

AIM

To mensure the physicochemical properties of three ceramic cement endodontic sealers AH Plus Bioceramic, Bio-C Sealer and Bio-C Sealer Ion+ with an epoxy resin sealer, AH Plus.

MATERIAL AND METHODS

These properties were measured: hardening time (HT), dimensional change (DC), solubility (SL), flow (FL) and radiopacity (RD). The distilled water obtained from the SL test was analyzed with atomic absorption spectrometry. A sample calculation was made considering n = 5 repetitions for each experimental sealer evaluated. Statistical analysis was performed using one-way ANOVA and post hoc Tukey tests (p < 0.05).

RESULTS

For the HT, AH Plus (484 ± 2.76 min) and AH Plus Bioceramic (424 ± 1.23 min) set more slowly than of Bio-C Sealer (370 ± 4.50 min) and Bio-C Sealer Ion+ (380 ± 1.42 min) (p < 0.05). AH Plus Bioceramic (12.56 ± 2.71 %) was more soluble than Bio-C Sealer (6.69 ± 1.67 %), Bio-C Sealer Ion+ (5.67 ± 2.16 %) and AH Plus (0.15 ± 0.01 %) (p < 0.05). AH Plus (0.03 ± 0.01 %) had slight expansion while the cement-based sealers had shrinkage: AH Plus Bioceramic (-1.60 ± 0.63 %) and Bio-C Sealer (-1.38 ± 0.69 %), Bio-C Sealer Ion+ (-5.19 ± 1.23 %) (p < 0.05). Bio-C Sealer Ion+ (59.80 ± 0.86 mm) and Bio-C Sealer (58.60 ± 0.98 mm) had the highest flow compared with AH Plus (56.90 ± 0.56 mm) and AH Plus Bioceramic (49.50 ± 0.63 mm) (p < 0.05). AH Plus (9.17 ± 0.06 mmAl) and AH Plus Bioceramic (8.27 ± 0.84 mmAl) showed radiopacity values when compared with those of Bio-C Sealer (4.90 ± 0.08 mmAl) and Bio-C Sealer Ion+ (4.14 ± 0.05 mmAl) (p > 0.05).

CONCLUSION

Ion release is inhered to these cement-based sealers and this result in calcium ion release.

Dislodgement resistance and structural changes of tricalcium silicate-based cements after exposure to different chelating agents

This study aimed to evaluate the dislodgement resistance and structural changes of different mineral trioxide aggregate cements (MTA) like Pro-Root MTA, Ortho MTA, and Retro MTA after exposure to sodium hypochlorite (NaOCl), NaOCl-Ethylenediaminetetraacetic acid (EDTA), 1-hydroxyethylidene-1, 1-bisphosphonate (Dual Rinse HEDP), and NaOCl-Maleic acid (MA). The root canal spaces of 150 dentine slices were obturated using tricalcium silicate cements and divided into 3 groups (n = 50): Group1: ProRoot MTA, Group2: Retro MTA, and Group3: Ortho MTA. The samples in each group were further subdivided into four experimental (n = 10) and one control groups (n = 10): 2.5% NaOCl-17% EDTA, Dual Rinse HEDP, 2.5% NaOCl-7% Maleic acid, 2.5% NaOCl, distilled water (control). The dislodgement resistance and structural changes of cements were measured. Use of DR HEDP resulted in higher dislodgement resistance compared to17% EDTA and 7% MA in the samples obturated with Ortho MTA and Pro-Root MTA (p<0.001). In Retro MTA group, samples treated with DR HEDP and 17% EDTA had higher dislodgment resistance compared to 7% MA (p<0.001). On microstructural and elemental analysis of all the three MTA cements, samples treated with 17% EDTA and 7% MA were more amorphous and granular when compared to DR HEDP, which was pettle shaped. Calcium level was decreased more in samples treated with 17% EDTA and 7% MA when compared to DR HEDP.

The solubility, pH value, chemical structure, radiopacity, and cytotoxicity of four different root canal sealers: an in vitro study

OBJECTIVE

The aim of this study was to investigate solubility, pH value, chemical structure, radiopacity, and cytotoxicity of AH Plus BC, TotalFill BC, AH Plus, and AH Plus Jet sealers.

MATERIALS AND METHODS

Cytotoxicity analysis with direct and extraction tests at 3 different concentrations (1:1, 1:2, 1:4 v/v%) and time (24 h, 48 h, and 72 h) on Saos-2, PdLF, and THP-1 cell lines, chemical structure with scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analysis, solubility, pH, and radiopacity values of AH Plus BC, TotalFill BC, AH Plus, and AH Plus Jet were evaluated. For statistical analyses of the groups, repeated measures, factorial, and one-way ANOVA tests were used. The statistical significance level was set at p < .05.

RESULTS

Resin-based sealers showed higher cytotoxicity values than the bioceramic-based sealers (p < 0.05). Time and concentrations were effective on the cell viabilities for cell lines. Higher peaks of calcium were detected bioceramic-based sealers and higher amount of zirconium was detected in AH Plus BC (p < 0.05). AH Plus BC showed similar radiopacity value with AH Plus, AH Plus Jet, whereas TotalFill BC showed the lowest radiopacity (p < 0.05). Bioceramic-based sealers had higher pH values in all experiment periods, and the difference between resin- and bioceramic-based sealer groups was significant (p < 0.05). However, the solubility values of the tested root canal sealers revealed no differences (p > 0.05).

CONCLUSIONS

The newly produced AH Plus BC Sealer showed similar properties with TotalFill BC, and their biological properties were better than AH Plus and AH Plus Jet.

CLINICAL RELEVANCE

AH Plus BC could be a possible alternative to other bioceramic- or resin-based sealers.

Retreatment of oval-shaped root canals filled with TotalFill bioceramic or AH plus sealer

This study investigated retreatment of oval canals filled with gutta-percha and different sealers using WaveOne Gold (WOG). Single oval canals were prepared to size 30, 0.04 and obturated with gutta percha and AH Plus (AHP) or TotalFill bioceramic (TFBC) sealer. After 6-month incubation, the canals were retreated with WOG Primary (25, 0.07) under simulated body temperature, and the developed load and torque were simultaneously measured. The time and regaining the apical patency were checked. Micro-computed tomography scanning was performed to calculate the remaining obturating materials. An independent t-test and chi-square test were performed at a 95% confidence level. A shorter retreatment time was needed in TFBC than in AHP (P = 0.003). However, a higher maximum apical load was reported with AHP (P = 0.000). Meanwhile, comparable maximum coronal load and maximum torque values were observed. Apical patency was regained in all TFBC roots and only 75% of the AHP samples (P = 0.217). The remaining obturating materials were comparable in TFBC (13.02 ± 8.12%) and AHP (10.11 ± 8.46%) (P = 0.398). WOG was able to remove 89.89% and 86.98% of obturating materials in TFBC and AHP, respectively. The TFBC presented lower apical loads and faster retreatment compared to AHP.

Impact of Final Irrigation Protocol on the Push-Out Bond Strength of Two Types of Endodontic Sealers

Aim: The aim of this study was to assess the impact of the final irrigation protocol on the push-out bond strength of calcium silicate-based sealers when compared to an epoxy resin-based sealer. Materials and Methods: Eighty-four single-rooted mandibular human premolars were shaped using the R25^® instrument (Reciproc, VDW, Munich, Germany) and then divided into three subgroups of 28 roots each depending on the final irrigation protocol: EDTA (ethylene diamine tetra acetic acid) and NaOCl activation, Dual Rinse^® HEDP (1-hydroxyethane 1,1-diphosphonate) activation or sodium hypochlorite (NaOCl) activation. Then, each subgroup was divided into two groups (14 each) according to the sealer used (AH Plus Jet^® or Total Fill BC Sealer^®) for single-cone obturation. Dislodgement resistance using a universal testing machine, samples' push-out bond strength and failure mode under magnification were determined. Results: EDTA/Total Fill BC Sealer^® showed significantly greater values of push-out bond strength compared with HEDP/Total Fill BC Sealer^® and NaOCl/AH Plus Jet^®, with no statistical difference with EDTA/AH Plus Jet^®, HEDP/AH Plus Jet^® and NaOCl/Total Fill BC Sealer^®, whereas HEDP/Total Fill BC Sealer^® showed significantly lower values of push-out bond strength. The apical third demonstrated higher means of push-out bond strength compared with middle and apical thirds. The most common failure mode was cohesive but showed no statistical difference compared to other types. Conclusions: Irrigation solution and final irrigation protocol affect the adhesion of calcium silicate-based sealers.

Update on citric acid use in endodontic treatment: a systematic review

This systematic review aims to analyse the available evidence concerning the use of citric acid (CA) in endodontics treatment and to assess its results in terms of different considerations: effect on smear layer removal, influence on sealer bond strength, activation effect by means of sonic or ultrasonic devices, effects on dentine surface, antibacterial activity, and effectiveness boost for regenerative procedures, releasing growth factors from dentin. To evaluate the results of CA as a final irrigant and compare them to other chelating agents. This review followed the PRISMA checklist. An electronic search was conducted in MEDLINE (OVID), Scopus (Elsevier) and the Web of Science (Thomson Reuters) databases. Risk of bias of included studies was evaluated using the modified CONSORT checklist and the PRIRATE checklist 2020 guidelines. 39 studies fulfilled the eligibility criteria to be included in this review: 27 in vitro studies using extracted human teeth, 10 in vitro studies using human dentin disks, and 2 RCT. Citric acid has proven to be effective in smear layer removal, showing better results in coronal and middle root thirds, improving its effect when combined with manual dynamic activation. There is no agreement regarding citric acid effect on sealer adhesion and adaptation to root canal walls due to heterogeneity within studies. Citric acid irrigation can decrease dentine microhardness and cause decalcification and erosion, especially when used before NaOCl. Citric acid has proven to be beneficial in regenerative endodontic procedures due to higher TGF-β1 release.Trial registration: Prospero database CRD42021267055.

An Updated Review on Properties and Indications of Calcium Silicate-Based Cements in Endodontic Therapy

Regarding the common use of calcium silicate cements (CSCs) in root canal therapy, their position in the context of past and present dentistry agents can provide a better understanding of these materials for their further improvement. In this context, the present review article addresses a wide range of recent investigations in the field of CSC-based products and describes details of their composition, properties, and clinical applications. The need for maintaining or reconstructing tooth structure has increased in contemporary endodontic treatment approaches. This research thus discusses the attempts to create comprehensive data collection regarding calcium ion release, bond strength, alkalinizing activity and bioactivity, and the ability to stimulate the formation of hydroxyapatite as a bioactive feature of CSCs. Sealing ability is also highlighted as a predictor for apical and coronal microleakage which is crucial for the long-term prognosis of root canal treatment integrity. Other claimed properties such as radiopacity, porosity, and solubility are also investigated. Extended setting time is also mentioned as a well-known drawback of CSCs. Then, clinical applications of CSCs in vital pulp therapies such as pulpotomy, apexification, and direct pulp capping are reviewed. CSCs have shown their benefits in root perforation treatments and also as root canal sealers and end-filling materials. Nowadays, conventional endodontic treatments are replaced by regenerative therapies to save more dynamic and reliable hard and soft tissues. CSCs play a crucial role in this modern approach. This review article is an attempt to summarize the latest studies on the clinical properties of CSCs to shed light on the future generation of treatments.

The Effect of Irrigation with Citric Acid on Biodentine Tricalcium Silicate-Based Cement: SEM-EDS In Vitro Study

There are various factors that may interfere with the activity of biomaterials during endodontic therapy. One of them is the canal system irrigation procedure with different rinsing solutions performed after the placement of bioactive cements. The authors investigate the influence of citric acid, a chelating agent, on the surface and the chemical composition of Biodentine tricalcium silicate-based cement using a multimethod approach. Twenty samples were divided into two groups based on the material setting time. They were subjected to citric acid irrigation with or without ultrasonic activation for 5 and 20 min. The chemical analysis was made with energy dispersive spectroscopy (EDS). The visual assessment of Biodentine surface was carried out in scanning electron microscope (SEM). The volume of material loss during the procedure was measured with Keyence optic microscope and dedicated digital software. Statistical analysis was performed. The results of the study show that the irrigation with citric acid influenced the surface appearance of the material and changed its chemical composition in both investigated groups. The ultrasonic activation (US) of the liquid has also aggravated its impact. Further research is needed to assess if that fact may change the sealing properties of the material influencing the long-term clinical outcome.

Assessment of Bioceramic Sealer Retreatability and Its Influence on Force and Torque Generation

This study assesses the retreatability of TotalFill bioceramic (TFBC) and AH Plus (AHP) sealers and their impact on retreatment force and torque. Twenty-six premolar teeth with single oval canals were instrumented, obturated using the matched gutta-percha cone technique with one of the tested sealers, and then temporized. After a 6-month incubation at 37 °C and 100% humidity, the canals were retreated with the XP Shaper system. During retreatment, the generated force and torque were measured. Micro-CT scanning was run before and after the retreatment procedure to analyze the remaining obturating materials in the canals. The apically directed maximum force in AHP was higher than that in TFBC. The coronally directed maximum force and the maximum torque were comparable between the groups. A higher amount of remaining obturating materials was found in the AHP compared to that in the TFBC. Based on these findings, endodontic sealer had an influence on retreatability, and the TFBC showed less remaining obturating materials and lower retreatment forces in the apical direction compared to the AHP in extracted teeth with oval canals.

Long-term porosity and retreatability of oval-shaped canals obturated using two different methods with a novel tricalcium silicate sealer

OBJECTIVE

To evaluate the percentage volume of voids and gaps in oval-shaped canals obturated using two different methods with a tricalcium silicate-based sealer after short- or long-term storage. The long-term effect of storage on the efficiency of removing filling material was also investigated.

MATERIALS AND METHODS

Forty premolar teeth with oval-shaped canals were instrumented to Reciproc R25 and obturated using single cone obturation (SCO) or warm vertical compaction (WVC) techniques with gutta-percha and HiFlow sealer. The specimens were stored at 100% humidity and 37°C for 2 weeks or 6 months and scanned using micro-computed tomography. Initial retreatment was performed up to a Reciproc R40, and the operating time was recorded. The residual material in the canal received a supplementary procedure using XP-endo Finisher R (XPFR) files. After each retreatment procedure, the specimens were rescanned.

RESULTS

The percentage volume of voids and gaps in the SCO group was higher than that of the WVC group at both 2 weeks and 6 months (P < 0.05). The percentage volume of the filling material removed after initial retreatment and XPFR cleaning was significantly higher in the 6-month group than in the 2-week groups (P < 0.05). The proportion of the residual material decreased significantly when XPFR files were used, compared to the initial retreatment group (P < 0.05) in both storage times.

CONCLUSION

The efficiency of retreatment in the oval-shaped canal was closely related to the storage time rather than the filling technique using a tricalcium silicate sealer. The XPFR instrument proved effective in the removal of the remaining materials from the oval-shaped canal.

CLINICAL RELEVANCE

Obturation of the oval-shaped canal with TSBS using the SCO technique in the coronal area needs to be optimized. The retreatment was less efficacious in freshly filled canals than aged filled canals.

Calcium Silicate-Based Root Canal Sealers: A Narrative Review and Clinical Perspectives

Over the last two decades, calcium silicate-based materials have grown in popularity. As root canal sealers, these formulations have been extensively investigated and compared with conventional sealers, such as zinc oxide-eugenol and epoxy resin-based sealers, in in vitro studies that showed their promising properties, especially their biocompatibility, antimicrobial properties, and certain bioactivity. However, the consequence of their higher solubility is a matter of debate and still needs to be clarified, because it may affect their long-term sealing ability. Unlike conventional sealers, those sealers are hydraulic, and their setting is conditioned by the presence of humidity. Current evidence reveals that the properties of calcium silicate-based sealers vary depending on their formulation. To date, only a few short-term investigations addressed the clinical outcome of calcium silicate-based root canal sealers. Their use has been showed to be mainly based on practitioners' clinical habits rather than manufacturers' recommendations or available evidence. However, their particular behavior implies modifications of the clinical protocol used for conventional sealers. This narrative review aimed to discuss the properties of calcium silicate-based sealers and their clinical implications, and to propose rational indications for these sealers based on the current knowledge.

Effect of exposure to root canal irrigants on the push-out bond strength of calcium silicate-based cements

OBJECTIVES

The aim of this study was to compare the push-out bond strength (POBS) of three calcium silicate-based cements (CSBC) after exposure to saline, sodium hypochlorite (NaOCl), ethylenediaminetetraacetic acid (EDTA), and a mixture of NaOCl and etidronic acid (NaOCl+HEBP) in simulated perforation.

MATERIALS AND METHODS

A total of 180 dentin slices were perforated and then filled with either Biodentine (BD), ProRoot MTA (PMTA), or Total Fill (TF). After 1 week, specimens in each group were divided into 4 subgroups (n = 15) according to the root canal irrigant (RCI) that their coronal surface was exposed to: saline, 5.25% NaOCl, 17% EDTA, or a mixture of 5.25% NaOCl and 9% HEBP (NaOCl+HEBP). A push-out test was performed, and the failure pattern was assessed. POBS data were analyzed with ANOVA and Tukey post hoc tests and the failure patterns with chi-square test.

RESULTS

No differences were found when comparing the effect of RCI on the POBS of PMTA. BD showed significantly higher POBS values after exposure to NaOCl+HEBP (p < .05), and those of TF were significantly lower after exposure to EDTA (p < .05). No differences in the failure patterns were found among groups.

CONCLUSION

NaOCl+HEBP had no detrimental effect on the POBS of CSBC.

CLINICAL RELEVANCE

The mixture of sodium hypochlorite and etidronic acid may be considered as an alternative irrigant when treating root perforations.

Custom and prefabricated PolyEtherKetoneKetone (PEKK) post-core systems bond strength: Scanning electron microscopy evaluation

The present study evaluated the bond strengths of prefabricated PolyEtherKetoneKetone (PEKK) posts, PEKK posts custom-configured according to root-canal size, and conventional fiber posts. A total of 30 maxillary incisors were randomly divided into three groups, as follows: Group 1: fiber posts; Group 2: prefabricated PEKK posts; Group 3; custom-made PEKK posts. Following endodontic treatment, post spaces were prepared, and posts were cemented with resin cement. Push-out bond strength testing was performed using a universal testing machine, and fractures modes were examined under a scanning electron microscope. Data were analyzed using One-way ANOVA and Tukey's HSD tests, with the level of significance set at .05. The highest bond-strength values in the cervical section were observed with the custom-made PEKK post (17.3470 MPa), whereas the highest bond-strength values in the middle and apical sections were observed with the conventional fiber posts (11.5375 MPa and 6.8625 MPa, respectively). Bond-strength values for all posts systems decreased in a cervical to apical direction. PEKK posts are a suitable alternative to fiber posts. Although custom-made PEKK posts demonstrated better bond strength than prefabricated PEKK posts, further studies are needed to evaluate their clinical performance.

Dentin Microhardness and Sealer Bond Strength to Root Dentin are Affected by Using Bioactive Glasses as Intracanal Medication

This study investigated the human dentin microhardness (MH) and the MTA Fillapex^® (Fillapex) and AH Plus^®(AH) bond strength (BS) to dentin after using calcium hydroxide (Ca(OH)₂) and bioactive glasses (45S5 and an experimental niobium phosphate bioactive glass (NbG)) as intracanal medications. For the MH test dentin slices were filled with medications and were submitted to Knoop MH (KHN) test (at day-0 (baseline data/without medication) and at day-15 (after using medication)). For the BS test, after medications had remained for 15 days in the roots, dentin slices were obtained and filled with the sealers. Seven days later, sealer BS to dentin was measured by push-out test (MPa). Data were statistically analyzed. Failure mode was visually assessed. The use of NbG, 45S5 for 15 days, increased the dentin MH and reduced the BS between AH sealer and dentin, but did not interfere with the Fillapex BS.

Peracetic acid as a single endodontic irrigant: effects on microhardness, roughness and erosion of root canal dentin

The aim was to assess the effects of 1% peracetic acid (PAA) as a single endodontic irrigant on microhardness, roughness, and erosion of root canal dentin, compared with 2.5% sodium hypochlorite (NaOCl) and with 2.5% NaOCl combined with 17% EDTA. Forty human, single-rooted tooth hemisections were submitted to Knoop microhardness test, before and after the following irrigation protocols: PAA = 1% PAA; NaOCl = 2.5% NaOCl; NaOCl-EDTA-NaOCl = 2.5% NaOCl +17% EDTA +2.5% NaOCl; and SS = saline. Another 40 roots were instrumented, irrigated with the same protocols, and sectioned longitudinally. The roughness analysis was performed on the mesial section using a confocal laser scanning microscope, whereas erosion was analyzed on each third of the distal section, using a scanning electron microscope. The data were analyzed using ANOVA and Tukey post-tests, and Kruskal-Wallis and Dunn post-tests (α = .05). The PAA and NaOCl-EDTA-NaOCl groups showed no significant differences (p > .05); both promoted reduction in microhardness and increase in roughness, compared with the NaOCl and SS groups (p < .05). NaOCl-EDTA-NaOCl promoted higher erosion in the cervical and middle thirds than the other groups (p < .05); there was no difference among PAA, NaOCl, and SS (p > .05). There was also no difference among the groups regarding the apical third (p > .05). PAA used as a single endodontic irrigant caused reduction in root canal dentin microhardness and increase in roughness in a similar way to NaOCl-EDTA-NaOCl; however, PAA caused less erosion than NaOCl-EDTA-NaOCl.

Correlation between Bond Strength to Dentin and Sealers Penetration by Push-Out Test and CLSM Analysis

This study correlated the bond strength (BS) and dentin penetration of different sealers by push-out test and Confocal Laser Scanning Microscopy (CLSM) analysis. Forty-five root canals were prepared according to the crown-down technique and filled with gutta-percha associated to the following sealers (n=15): Endofill, AH Plus and MTA Fillapex. Five canals of each group were filled with the sealers added with 0.1% Rhodamine B dye. Next, the specimens were transversely sectioned and submitted to the push-out test (n=10) and CLSM analysis (n=5). The BS data showed the following means (MPa) and standard deviation: AH Plus (4.17±1.86); MTA Fillapex (3.13±1.96) and Endofill (2.10±1.03). Statistical analysis (two-way ANOVA, α=0.05) showed significant difference among sealers (p<0.001) and root canal thirds (p<0.001). The BS results of Endofill and MTA Fillapex were statistically similar (p>0.05), however, they were statistically different from AH Plus (p<0.001). The regional analysis of BS showed similarity between middle and apical thirds (p>0.05), and both were different from coronal portion (p<0.001). CLSM analysis verified tags formation in all groups and higher penetration of the specimens filled with AH Plus (p<0.05). The Kendall test (correlation between BS to dentin and sealer penetration into dentinal tubules) and the Pearson test (between failures pattern and sealer penetration into dentinal tubules) did not show correlation between the variables evaluated for all the tested sealers (p>0.05). AH Plus group had higher BS to dentin, and deeper tags formation than the other sealers. There was no significant correlation between BS and intratubular penetration of the tested sealers.

Shear bond strengths of calcium silicate-based sealer to dentin and calcium silicate-impregnated gutta-percha

AIM

To compare the shear bond strengths of a calcium silicate-based root canal sealer (CSS), to dentin or calcium silicate-impregnated gutta-percha (CSGP), with the shear bond strengths of an epoxy resin-based sealer.

METHODS

For sealer/dentin testing, 40 hemisectioned roots were divided into 2 groups. Coronal root dentin discs were bonded with CSS or epoxy resin-based sealer. For sealer/core material testing, CSGP and conventional gutta-percha discs were bonded with a matching sealer (N = 20 per group). The shear bond strengths were tested using a universal testing machine. The failed modes were analyzed using stereomicroscopy and scanning electron microscopy.

RESULTS

The CSS sealer had significantly higher shear bond strength to dentin than did epoxy resin-based sealer (P < .01). However, shear bond strengths of the 2 sealers to core materials did not significantly differ (P = .74). The remnants of the CSS sealer adhering to dentin or calcium silicate gutta-percha disc were observed.

CONCLUSIONS

The CSS sealer had better adhesion to dentin than did epoxy resin-based sealer. However, the bond of the CSS sealer to impregnated gutta-percha was not superior to the epoxy resin-based sealer bonded to conventional gutta-percha.

An in vitro comparative evaluation of the effect of three endodontic chelating agents (17% ethylenediamine tetraacetic acid, 1% peracetic acid, 0.2% chitosan) on the push out bond strength of gutta percha with a new bioceramic sealer (BioRoot RCS)

Aim:

This study aims to evaluate the effect of three endodontic chelating agents (17% ethylenediamine tetra-acetic acid [EDTA], 1% peracetic acid [PAA], 0.2% Chitosan) on the push out bond strength of gutta percha with a new bioceramic sealer (BioRoot RCS).

Materials and Methods:

Forty-eight single-rooted mandibular premolars were selected and decoronated to obtain standardized root length of 15 mm. The root canals were prepared up to #30 files (Hyflex CM) and copious irrigation was done with 3 ml of 5.25% of NaOCl. According to the final irrigation, specimens were divided into three groups: Group 1 (n = 16) 0.2% chitosan, Group 2 (n = 16) 17% EDTA, and Group 3 (n = 16) 1% PAA for 1 min. Samples from each group were obturated with bioceramic sealer and gutta percha and sealed with temporary filling material. Two horizontal slices of 2 mm was obtained from the middle third of each sample (n = 32). Push out bond strength and failure modes were assessed. Kruskal–Wallis test followed by Mann–Whitney post hoc analysis was used for push out analysis. Chi square test was used to compare the modes of failure. The statistical significance level was set at P = 0.05.

Results:

The highest push out bond strength was obtained with Group 1 (0.2% chitosan) followed by Group 3 (1% PAA). Group 2 (17% EDTA) showed least push out bond strength when compared to Group 1 (0.2% chitosan) and Group 3 (1% PAA). The mode of failure was mainly cohesive for all groups.

Conclusions:

The highest push-out bond strength of BioRoot RCS was seen after treatment with 0.2% chitosan while the least was after EDTA treatment. 1% PAA treatment also favorably affected push-out bond strength of BioRoot RCS.

The push out bond strength of polydimethylsiloxane endodontic sealers to dentin

Background

The purpose of this experiment was to assess the push out bond strength of Polydimethylsiloxane sealers (GuttaFlow 2 and GuttaFlow Bioseal by Colte’ne/Whaledent, Altstätten, Switzerland). AH Plus (Dentsply, DeTrey, Konstanz, Germany) was used as a reference material for comparison.

Methods

Thirty root slices were prepared from the middle third of 10 mandibular premolars. Each slice was 1 ± 0.1 mm thick. Three holes, 0.8 mm wide each, were drilled on the axial side of each root slice. These holes were subjected to standardized irrigations and then dried using paper points. Finally, for each root slice, each hole was filled with exactly one of the following three root canal sealers: AH Plus, GuttaFlow 2 and GuttaFlow Bioseal. After all the holes were filled in that way, the root slices were stored on top of phosphate-buffered saline solution (pH 7.2) soaked gauze for 7 days at the temperature of 37 degrees Celsius. Then, for each root canal sealer on a root slice, the universal testing machine was used to measure the push out bond strength. The differences in push out bond strengths between the three sealer samples were assessed using the Friedman test, while the paired comparisons were assessed using Wilcoxon signed rank test with Bonferroni correction. All statistical tests were two-tailed and the significance level was set at the 5%.

Results

According to the Friedman test the distributions of push out bond strengths of AH Plus, GuttaFlow 2 and GuttaFlow Bioseal were different (P < 0.05). Paired comparisons indicated that AH Plus had a significantly superior push out bond strength than GuttaFlow 2 and GuttaFlow Bioseal, while the push out bond strength of GuttaFlow Bioseal was significantly stronger than that of GuttaFlow 2 (P < 0.01).

Conclusions

Based on these findings, AH Plus is a better root canal sealer than GuttaFlow 2 and GuttaFlow Bioseal.

Effect of peracetic acid used as single irrigant on the smear layer, adhesion, and penetrability of AH Plus

The aim of this study was to evaluate the effect of peracetic acid (PAA) as a single irrigant on the smear layer, on the intraradicular dentinal bond strength, and on the penetrability of an epoxy-based resin sealer into the dentinal tubules. A total of 120 roots were distributed into 4 groups according to the irrigant used in root canal preparation: 1% PAA (PAA); 2.5% NaOCl followed by final irrigation with 17% EDTA and 2.5% NaOCl (NaOCl-EDTA-NaOCl); 2.5% NaOCl (NaOCl); and saline solution (SS). The smear layer was evaluated using scanning electron microscopy. The bond strength of an epoxy-based resin sealer (AH Plus) to root dentin was evaluated by the push-out test and penetrability of the sealer into dentinal tubules was observed by confocal laser microscopy. The results were analyzed by the Kruskal-Wallis and the Dunn post-test (α = 0.05). The use of 1% PAA as single root canal irrigant provided smear layer removal and improved the penetrability and bond strength of AH Plus to root dentin in a manner similar to that of the NaOCl-EDTA-NaOCl group (p > 0.05). The NaOCl and SS groups had higher values of smear layer and lower values of sealer penetrability and dentin bond strength than the PAA and NaOCl-EDTA-NaOCl groups (p < 0.05). Thus, 1% PAA has the potential to be used as a single irrigant in root canals.

The push-out bond strength of BIOfactor mineral trioxide aggregate, a novel root repair material

Objectives

The aim of this in vitro study was to evaluate the push-out bond strength of a novel calcium silicate-based root repair material-BIOfactor MTA to root canal dentin in comparison with white MTA-Angelus (Angelus) and Biodentine (Septodont).

Materials and Methods

The coronal parts of 12 central incisors were removed and the roots were embedded in acrylic resin blocks. Midroot dentin of each sample was horizontally sectioned into 1.1 mm slices and 3 slices were obtained from each root. Three canal-like standardized holes having 1 mm in diameter were created parallel to the root canal on each dentin slice with a diamond bur. The holes were filled with MTA-Angelus, Biodentine, or BIOfactor MTA. Wet gauze was placed over the specimens and samples were stored in an incubator at 37°C for 7 days to allow complete setting. Then samples were subjected to the push-out test method using a universal test machine with the loading speed of 1 mm/min. Data was statistically analyzed using Friedman test and post hoc Wilcoxon signed rank test with Bonferroni correction.

Results

There were no significant differences among the push-out bond strength values of MTA-Angelus, Biodentine, and BIOfactor MTA (p > 0.017). Most of the specimens exhibited cohesive failure in all groups, with the highest rate found in Biodentine group.

Conclusions

Based on the results of this study, MTA-Angelus, Biodentine, and BIOfactor MTA showed similar resistances to the push-out testing.

The influence of the irrigant QMix on the push-out bond strength of a bioceramic endodontic sealer

Purpose

The aim of this study was to evaluate the effect of a commercially available irrigant, the Qmix 2 in 1, on the push out bond strength of Endosequence BC which is a bioceramic based root canal sealer.

Material and methods

Sixty extracted maxillary central incisors were prepared with Protaper Next rotary instrument up to X4 (# 40). The specimens were randomly divided into four groups of equal sample size (n=15), according to the final irrigation regimen as follows: Group 1: 2.5% sodium hypochloride (NaOCl) (control), Group 2: 17% ethylenediaminetetraacetic acid (EDTA), Group 3: 2% Chlorhexidine (CHX), Group 4: QMix 2 in 1. After rinsing, teeth were obturated using gutta-percha with Endosequence BC sealer. Slices were obtained from coronal, middle, and an apical section of the root canal. Push-out test was performed to evaluate the bond strength between the root canal dentin and the sealer. Data was statistically analyzed.

Results

The push-out bond strength of the root canal sealer was significantly affected by the type of irrigation solution. Highest bond strengths were found in canals irrigated with Qmix solution, and these results were regardless of anatomical section of the root canal (p< 0.05).

Conclusion

Final irrigation of the root canals with QMix had a positive effect on the bond strength of Endosequence BC sealer throughout the root canal.

Push-Out Bond Strength and SEM Evaluation in Roots Filled with Two Different Techniques Using New and Conventional Sealers

The aim of this study was to evaluate the influence of calcium-silicate-based sealer (Endosequence-BC-Sealer) in roots, filled with thermo-plasticized injectable technique aided by Calamus-Flow-Delivery-System, on bond strength to radicular dentin, in comparison with conventional epoxy-resin-based sealer (AH-Plus) along with cold-lateral-compaction technique. Root canals of mandibular-premolar teeth (n = 80) were instrumented using Protaper Universal rotary files and were randomly divided into four experimental groups (n = 20) as follows: (1) AH-Plus + cold-lateral-compaction technique; (2) Endosequence-BC-Sealer + cold-lateral-compaction technique; (3) AH-Plus + thermo-plasticized injectable technique; and (4) Endosequence-BC-Sealer + thermo-plasticized injectable technique. Horizontal disc shaped samples from each group (n = 60/group) were obtained and push-out bond strength testing was performed at a cross-head speed of 0.5 mm/min. Data were analyzed statistically using nonparametric Kruskal-Wallis analysis and Mann-Whitney test (p < 0.001). The statistical analysis revealed a significant difference amongst the groups (p < 0.001). The highest bond strength values were found in group 1 compared with all the other experimental groups (p < 0.001), whereas the lowest bond strength values were found in group 4 (p < 0.001). It was concluded that thermo-plasticized injectable technique with Calamus-Flow-Delivery-System lowered the bond strengths of the sealers, especially Endosequence-BC-Sealer. Therefore, this technique is not recommended to calcium-silicate-based sealers. Further studies are needed to confirm the findings of this study.

The push-out bond strength of calcium silicate-based endodontic sealers

Background

The aim was to compare the dislodgement resistance of calcium silicate-based sealers (Total Fill BC Sealer, Endo CPM Sealer, BioRoot RCS) with an epoxy resin-based sealer (AH Plus).

Methods

The root canals of 80 single-rooted human teeth were instrumented with F360 up to size 45.04. All canals were obturated using matching gutta-percha cones according to the single-cone technique in combination with one of the mentioned sealers (n = 20 per group). After eight weeks of incubation (37 °C, 100% humidity), the roots were embedded in resin. Starting with a distance of 7 mm from the apex, four slices of 1 mm thickness were cut. Dislodgement resistance was measured using a universal testing machine and the push-out bond strength was calculated. Specimens were examined under 4×-magnification to determine the mode of bond failure. Statistical analysis was performed using ANOVA and Student-Newman-Keuls-test.

Results

Regarding the pooled data of all sections, the push-out bond strength of AH Plus was significantly higher than the push-out bond strength of all calcium silicate-containing sealers (P < 0.05). Out of all calcium silicate-based sealers, Total Fill BC Sealer showed the highest push-out bond strength (P < 0.05). BioRoot RCS had significant higher push-out bond strength than Endo CPM Sealer (P < 0.05). Nearly the same results were found for all four sections. BioRoot RCS only differed significantly from Endo CPM Sealer in the third section (P < 0.05).

Conclusions

The push-out bond strength of the investigated calcium silicate-based sealers was lower than of AH Plus. Total Fill BC showed the highest push-out bond strength of the calcium silicate-based sealers.

Effect of root canal irrigation protocols on the dislocation resistance of mineral trioxide aggregate-based materials: A systematic review of laboratory studies

The aim of this systematic review was to address the question: Do different irrigating protocols have an impact on the dislocation resistance of mineral trioxide aggregate (MTA)-based materials? The review was performed using a well-defined search strategy in three databases (PubMed, Scopus, Web of Science) to include laboratory studies performed between January 1995 and May 2017, in accordance with PRISMA guidelines. Two reviewers analysed the papers, assessed the risk of bias and extracted data on teeth used, sample size, size of root canal preparation, type of MTA-based material, irrigants, canal filling method, storage method and duration, region of roots and the parameters of push-out testing (slice thickness, plunger dimensions and plunger loading direction), the main results and dislocation resistance values (in MPa). From 255 studies, 27 were included for full-text analysis. Eight papers that met the inclusion criteria were included in this review. There was a wide variation in dislocation resistance due to differences in irrigation sequence, time and concentration of irrigants, storage method and duration, and the parameters of push-out bond strength testing. A meta-analysis was not done but qualitative synthesis of the included studies was performed. No definitive conclusion could be drawn to evaluate the effect of irrigation protocols on dislocation resistance of MTA-based materials. Recommendations have been provided for standardized testing methods and reporting of future studies, so as to obtain clinically relevant information and to understand the effects of irrigating protocols on root canal sealers and their interactions with the dentine walls of root canals.

Design Variability of the Push-out Bond Test in Endodontic Research: A Systematic Review

INTRODUCTION

There is limited literature on the impact of testing variables on the push-out bond test (POBT). This review identified designs of the POBT used in the endodontic literature and aimed to determine which experimental variables may influence the push-out bond strength (POBS).

METHODS

A systematic review based on PRISMA guidelines was performed by searching the PubMed, SCOPUS, and Cochrane library databases using terms including push-out and dislocation resistance and descriptions of endodontic materials. Test variables assessed included method of root preparation, timing of sectioning compared with filling, thickness, diameter and taper of sections, and plunger size and velocity. The POBS of 3 common materials (gutta-percha and AH Plus, mineral trioxide aggregate, and Biodentine) were collected from investigations, and a comparison was attempted.

RESULTS

One hundred thirty-three studies assessed the POBS of root-filling materials, 68 assessed root repair cements/root-end filling materials, and 16 assessed orifice barrier materials other than mineral trioxide aggregate. There was significant variation in all of the assessed variables, resulting in a large range of reported values for the POBS of the various materials. Because of this heterogeneity in study design, no further statistical analysis of the impact of the test variables on POBS was possible.

CONCLUSIONS

There was considerable variation in the POBT design used in endodontic research. Greater standardization is required for future research as well as accurate reporting for all test variables to assess the impact of specific design variables on POBS.

Apically extruded debris during the removal of canal filling material from root canals using three techniques

AIM

In the present study, we evaluated the effect of the single-cone technique (SCT), cold lateral compaction (CLC), and wave vertical compaction (WVC) technique performed using two different sealers on the amount of apically extruded debris (AED) produced during the removal of canal filling material.

METHODS

Ninety extracted mandibular premolars were prepared with ProTaper instruments. The teeth were then randomly assigned to six groups (N = 15) for root canal filling: (a) group 1, CLC+AH Plus; (b) group 2, SCT+AH Plus; (c) group 3, WVC+AH Plus; (d) group 4, CLC+MTA Fillapex; (e) group 5, SCT+MTA Fillapex; and (f) group 6, WVC+MTA Fillapex. In all groups, the removal of canal filling material was performed with ProTaper retreatment instruments. The mean weight of the AED was assessed with an analytical balance.

RESULTS

The amount of AED was lowest in groups 2 and 5 (P < .05), with no difference between these groups (P > .05). Groups 3 and 6 produced the greatest amount of extruded debris (P < .05); there was no difference between these groups (P > .05). Additionally, there was no difference between groups 1 and 4 (P > .05). There was no significant difference among the groups regarding sealer type (P > .05).

CONCLUSIONS

The canal filling technique used affected the amount of AED produced during the removal of canal filling material, but not sealer type.

Effect of novel chelating agents on the push-out bond strength of calcium silicate cements to the simulated root-end cavities

To compare the effects of different chelating agents on the push-out bond strength of calcium silicate-based cements to the simulated root-end cavities. Root-end cavities were prepared on the roots of fifty extracted maxillary anterior teeth. The specimens were then randomly divided into 5 groups (n = 10) based on the final irrigation regimen: Group 1: 17% EDTA, Group 2: 7% maleic acid, Group 3: QMix, Group 4: 2.25% peracetic acid (PAA), Group 5: 0.9% saline. Then, the samples from each group were subdivided into two groups (n = 5) based on the apical filling material. In group 1, root-end cavities of all samples were filled with Biodentine and in group 2, with MTA. Each sample was horizontally sectioned to produce two discs of ∼1 mm thick per specimen. The maximum load required for the dislodgement of 100 retrofillings was recorded. The specimens were examined under scanning electron microscope after debonding to assess the type of bond failure. Data were statistically analyzed using Kruskal Wallis and Mann Whitney U tests. Irrigation with saline resulted in higher bond strength compared to the other irrigants in the retrograde cavities obturated with MTA or Biodentine (p < .05). In MTA group, there was no significant difference between the test irrigants (p > .05). EDTA and PAA groups showed higher dislodgement resistance values than the other test irrigants, when Biodentine was used as a filling. The type of irrigation solution influences the bond strength of the root-end fillings.

Push-out bond strength of three different calcium silicate-based root-end filling materials after ultrasonic retrograde cavity preparation

OBJECTIVE

The aim of this study was to evaluate the bond strength of three calcium silicate-based root-end filling materials.

MATERIALS AND METHODS

The root canals of 30 single-rooted teeth were endodontically treated; their root ends were resected and root-end cavities were prepared using ultrasonic tip. The teeth were randomly divided into three groups according to the material: (1) Micro-Mega mineral trioxide aggregate (MM-MTA), (2) Biodentine, and (3) TotalFill root repair material (RRM). Push-out test was performed using universal testing machine, and failure mode was analyzed by stereomicroscope. The data were statistically analyzed using Kruskal-Wallis and Man-Whitney post hoc tests. All p values < 0.05 were considered significant.

RESULTS

TotalFill RRM exhibited significantly higher bond strength (12.69 MPa) than Biodentine (9.34 MPa, p = 0.023) and MM-MTA (7.89 MPa, p = 0.002). The difference between Biodentine and MM-MTA was not significant (p = 0.447). Mixed failures were the most noted in all three groups. MM-MTA had more adhesive failures than Biodentine and TotalFill, and no cohesive failures, but without statistical significance (p = 0.591).

CONCLUSION

The bond strength was the highest for TotalFill RRM.

CLINICAL RELEVANCE

In order to provide a persistent apical seal, root-end filling materials should resist dislodgement under static conditions, during function and operative procedures. TotalFill RRM exhibited higher bond strength to dentin than MM-MTA and Biodentine.

Physicochemical Properties and Volumetric Change of Silicone/Bioactive Glass and Calcium Silicate-based Endodontic Sealers

INTRODUCTION

This study evaluated setting time (ST), radiopacity, pH, flow, solubility, and volumetric change (VC) of a silicone, gutta-percha, and bioactive glass-based sealer, GuttaFlow Bioseal (GFB), and a calcium silicate-based sealer, TotalFill BC Sealer (TFBC), in comparison with AH Plus.

METHODS

ST and flow were evaluated in accordance with the ISO 6876 Standard. pH was evaluated after different time intervals (1, 3, 7, 14, 21, and 28 days). Radiopacity was evaluated by radiographic analysis in millimeters of aluminum. Solubility was evaluated by means of mass loss (%) after 7 and 30 days of immersion in distilled water. VC was evaluated by micro-computed tomography, by using cavities 3 mm deep and 1 mm in diameter in acrylic resin, filled with the materials. The materials were evaluated after setting and after 7 and 30 days of immersion in distilled water. The data were submitted to analysis of variance and Tukey statistical tests (P < .05).

RESULTS

TFBC demonstrated the highest pH and solubility. GFB had the shortest ST, and lowest radiopacity and flow values. VC was similar for the sealers in both time intervals.

CONCLUSIONS

TFBC presented the highest pH and solubility, but showed similar VC to GFB and AH Plus. GFB showed proper physicochemical properties. Micro-computed tomography complements the physicochemical analysis of endodontic sealers.

Composition and physicochemical properties of calcium silicate based sealers: A review article

Background

Recently a new generation of endodontic sealers has been developed based on calcium silicate as MTA Fillapex, Endoseal MTA, Total Fill BC Sealer, EndoSequence BC Sealer, iRoot SP, Endo CPM sealer, MTA-Angelus and ProRoot Endo Sealer. A review of literature was conducted to discuss the composition, physicochemical properties, and clinical perspectives of calcium silicate based sealers.

Material and Methods

A literature search was conducted in PubMed and web of knowledge databases with appropriate MeSh terms and keywords. A total of 71 studies were reviewed for data extraction.

Results and Conclusions

Calcium silicate based sealers showed suitable physical properties to be used as an endodontic sealer. However, its high solubility remains an important issue. They show good performance regarding calcium ion release, film thickness, and fowability. More researches are required about features of calcium silicate based sealers before recommending them for clinical applications.

Key words:Calcium silicate, root canal filling materials, composition, physical properties.

Effect of Intra-Canal Calcium Hydroxide Remnants on the Push-Out Bond Strength of Two Endodontic Sealers

INTRODUCTION

The aim of this study was to evaluate the effect of intra-canal calcium hydroxide (CH) remnants after ultrasonic irrigation and hand file removal on the push out bond strength of AH-26 and EndoSequence Bioceramic sealer (BC Sealer).

METHODS AND MATERIALS

A total of 102 single-rooted extracted human teeth were used in this study. After root canal preparation up to 35/0.04 Mtwo rotary file, all the specimens received CH dressing except for 34 specimens in the control group. After 1 week, the specimens with CH were divided into 2 groups (n=34) based on the CH removal technique; i.e. either with ultrasonic or with #35 hand file. Then specimens were divided into two subgroups according to the sealer used for root canal obturation: AH-26 or BC Sealer. After 7 days, 1 mm-thick disks were prepared from the middle portion of the specimens. The push out bond strength and failure mode were evaluated. Data were analyzed by the two-way ANOVA and Tukey's post hoc tests.

RESULTS

The push out bond strength of both sealers was lower in specimens receiving CH. These values were significantly higher when CH was removed by ultrasonic (P<0.05). The dominant mode of failure in all subgroups was of mixed type except for the BC Sealer specimens undergoing CH removal with hand file which dominantly exhibited adhesive mode of failure.

CONCLUSION

CH remnants had a negative effect on the push out bond strength of AH-26 and BC Sealer. Ultrasonic irrigation was more effective in removing CH.