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

A 4-year follow-up of root canal obturation using a calcium silicate-based sealer and a zinc oxide-eugenol sealer: A randomized clinical trial

AIM

This randomized clinical trial assessed the outcomes of nonsurgical root canal treatment (RCT), comparing a calcium silicate-based sealer (CSBS) with the single-cone technique (SC) with a zinc oxide-eugenol (ZOE) sealer and warm vertical compaction (WVC).

METHODOLOGY

Ninety-two single- and multi-rooted teeth were divided into two groups and treated using either the SC with BioRoot™ RCS (BIO) or WVC with Pulp Canal Sealer™ EWT (PCS). Teeth with apical periodontitis (AP) in both groups were further divided into BIOAP and PCSAP subgroups. Standardized instrumentation and disinfection protocols were followed. Periapical index (PAI) was recorded, and clinical and radiographic follow-ups were conducted at 1, 3, 6, 12, 24, and 48 months. Outcomes considered included success rate (under strict and loose criteria), extraction, length of filling, voids, and extrusion rate, as well as changes in PAI score from baseline. Outcome variables and prognostic factors were analysed using binary and multiple logistic regression at p < .05.

RESULTS

Sixty-seven teeth were included (recall rate, 73%). At 4-year follow-up, the overall success rates (BIO + PCS) were 89.6% by loose criteria and 83.3% by strict criteria. Subgroup success rates (BIOAP+PCSAP) were 88.5% by loose criteria and 80.4% by strict criteria. There were no significant differences between the groups in terms of success rate, extraction rate, length of filling, voids, or extrusion (p > .05). The pattern of PAI reduction was similar in both groups (p = .806).

CONCLUSION

Treatment using the SC-CSBS technique and the ZOE sealer with the WVC technique demonstrated a similar success rate.

Comparative Assessment of Push-Out Bond Strength and Dentinal Tubule Penetration of Different Calcium-Silicate-Based Endodontic Sealers

Background: Adhesion within endodontic obturation material and root canal walls improves the efficacy of the endodontic treatment by establishing a barrier that inhibits reinfection and entombs residual bacteria. This study evaluates the push-out bond strength (POBS) of calcium silicate sealers compared to an epoxy-resin-based sealer. Methods: A total of 36 extracted mono-radicular teeth were prepared with Pro Taper Ultimate and irrigated with 5.25% sodium hypochlorite and 17% EDTA. The specimens were randomly split into three groups (n = 12) according to the endodontic sealer and filling technique used as follows: Ah Plus with the continuous wave condensation technique (CWC), Ah Bioceramic (Ah Bio) with the single-cone technique, and Total Fill Hi-Flow (FKG Hi-Flow) with the CWC technique. The material was allowed to set for 4 weeks, and afterwards, the roots were placed in acrylic resin and sectioned into 1 mm transverse slices. A POBS test was conducted using a universal testing machine, and the mode of bond failure was assessed at 4× magnification using a stereomicroscope. Six specimens from each group were selected for SEM-EDX examination to evaluate dentinal tubule penetration. The data were analysed using analysis of variance and Tukey and Bonferroni post hoc tests. Results: The POBS tests revealed higher values for Ah Plus in comparison to both calcium silicate sealers (p < 0.001), while FKG Hi-Flow showed superior results to Ah Bio (p < 0.001). The cohesive mode of failure was prevalent in all three groups. Conclusions: In conclusion, the resin-based sealer showed higher bond strength and better dentinal tubule penetration than the two calcium silicate sealers tested, while FKG Hi-Flow outperformed AH Bio.

Immediate and delayed shear bond strength evaluation between root canal sealers and restorative materials: an experimental study

BACKGROUND

Several calcium silicate-based sealers have recently emerged in endodontics. This study aimed to compare the immediate and delayed shear bond strength between the bioceramic and calcium hydroxide-based sealers and different resin-based restorative materials.

METHODS

One hundred and twenty specimens with a 3-mm depth and a 3-mm diameter were prepared. They were evenly divided into two groups, the bioceramic sealer and calcium hydroxide-based sealer groups. Each primary group was subdivided into two subgroups based on the restorative material used; i.e., the flowable resin composite and resin-modified glass ionomer subgroups. Moreover, each subgroup was further divided into the restoration process's timing: either immediately post-sealing or delayed after setting the sealers for seven days. The mode of failure was assessed by stereomicroscopic examination.

RESULTS

The highest shear bond strength was found when the bioceramic sealer was used and restored with the flowable resin composite. The strengths were 8.45 (1.17) and 6.67 (1.60) megapascals (MPa) in the immediate and delayed restoration groups, respectively. In contrast, the lowest strength, 2.91 (1.22) MPa, was recorded when calcium hydroxide-based sealer was employed and restored after allowing the sealer to set completely with resin-modified glass ionomer. Notably, there were no cohesive fractures within the tested restorative materials. All observed fractures occurred within the sealer materials, at the interface of the sealer and restorative material, or in combination. Moreover, the most common failure was a mixed failure.

CONCLUSIONS

When flowable resin composite was used immediately before complete setting, bioceramic sealers showed a higher bond strength than calcium hydroxide-based sealers.

Influence of Initial Root Canal Treatment on Intratubular Penetrability and Bond Strength of Nonsurgical Retreatment: An InVitro Study

INTRODUCTION

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). 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; and BCS/BCS. Four samples from each subgroup received the addition of fluorophores to the sealer for penetrability analysis using laser scanning confocal fluorescence microscopy. 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 (20× magnification). BS data were analyzed using two-way analysis of variance followed by Tukey's test (P < .05), and the association between the failure pattern and BS value was assessed using the chi-square test (P < .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 < .05), with a higher percentage of adhesive failures to the filling material for all groups. Laser scanning confocal fluorescence microscopy 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.

Impact of different disinfection protocols on the bond strength of NeoMTA 2 bioceramic sealer used as a root canal apical plug (in vitro study)

INTRODUCTION

Treatment of an immature permanent tooth required a special disinfection protocol due to the presence of thin radicular walls, which are prone to fracture. Mineral Trioxide Aggregate (MTA) has been proposed as a root repair material for root canal treatment. The aim of this in vitro study was to compare the push-out bond strength of conventional White MTA cements and second generation NeoMTA 2 in imitated immature roots treated with different disinfection protocols, which are 5.25% sodium hypochlorite (NaOCl), followed by 17% ethylenediaminetetraacetic acid (EDTA), and NaOCl, followed by 20% etidronic acid (HEBP).

METHODS

The root canals of freshly extracted single-root teeth were manually prepared until 90 K-file to imitate immature roots. Roots were randomly divided into four groups (G) according to the disinfection protocol (n = 15 per group). where G1 (NaOCl + EDTA + White MTA) and G2 (NaOCl + EDTA + NeoMTA 2) While G3 (NaOCl + HEBP + White MTA) and G4 (NaOCl + HEBP + NeoMTA 2) All groups were activated with manual agitation. All specimens were incubated for 48 h. The apical third of each root was perpendicularly sectioned to attain a slice of 3 mm thickness. Push-out bond strength values were assessed using a two-way ANOVA and a Student's t test.

RESULTS

G3 and G4 that were treated with HEPB showed higher significant push-out bond strength mean values than G1 and G2 treated with an EDTA chelating agent. Irrespective of the chelating agent used, it was found that both NeoMTA 2 and White MTA had no significant influence on push-out bond strength mean values (p ≤ 0.05).

CONCLUSION

The combined use of 5.25% NaOCl and 20% HEBP increased the push-out strength values of both NeoMTA 2 and White MTA, rendering them suitable to be used as an alternative chelating agent to EDTA.

Influence of sealer and supplementary approach on filling material removal during endodontic retreatment

Both root canal sealer-based and supplementary protocols may influence removal of filling material during endodontic retreatment. Mesial root canals of extracted mandibular molars were prepared using HyFlex EDM 25/.08, and filled with a calcium silicate sealer (Bio-C Sealer), or an epoxy resin (AH Plus), using the single cone technique (n = 12). Retreatment was performed using ProDesign Logic (PDL) RT and PDL 35/.05. The specimens were randomly divided into two experimental groups (n = 12), and the sealers were distributed similarly. A supplementary protocol was performed with PDL 50/.01 or XP-endo Finisher. Root canal transportation and volume, in addition to the remaining filling material percentage were evaluated using high-resolution (5 µm voxel size) micro-CT. Statistical analysis was performed using t-tests (α = 0.05). Root canals filled with AH Plus presented high residual filling material (p < 0.05). Both protocols decreased residual volume of filling material in the apical third (p < 0.05). PDL 50/.01 increased the apical root canal volume (p < 0.05). No difference was observed between the systems regarding canal transportation (p > 0.05). In conclusion, AH Plus is more difficult to remove from the apical third than Bio-C Sealer. PDL 50/.01 and XP-endo Finisher enabled greater removal of filling materials in the apical third, in the retreatment of curved root canals, without promoting apical transport.

Comparative evaluation of dentinal tubule penetration and push-out bond strength of new injectable hydraulic calcium disilicate based root canal sealer: A single blinded in vitro study

Objective

To evaluate and compare dentinal tubule penetration and push-out bond strength of BIO-C ION+, AH Plus and NanoSeal-S using Confocal Laser Scanning Microscopy (CLSM) and Universal Testing Machine (UTM).

Materials & method

Sixty human mandibular premolars were prepared using ProTaper Gold till F3. Samples were then divided into 3 groups: Group I (n = 20) BIO-C ION + sealer, Group II (n = 20) AH Plus and Group III (n = 20) NanoSeal-S sealer. Groups were then sub-divided into two sub groups: In Subgroup A (n = 10) samples were obturated using single-cone with 0.1 % Rhodamine B dye and in Subgroup B (n = 10) samples were obturated using single cone. The samples were then transversely sectioned into coronal, middle and apical segments, samples in subgroup A & B were then submitted to CLSM analysis and UTM respectively.

Results

The Bond Strength data showed following means (MPa): Group I Subgroup B: (BIO-C ION+) coronal (1.64), middle (1.25), apical (0.93); Group II Subgroup B: (AH Plus) coronal (2.20), middle (1.85) apical (1.38) and Group III Subgroup B: (NanoSeal-S) coronal (1.26), middle (0.94), apical (0.58). The dentinal tubule penetration data showed following means: (μm) Group I Subgroup A (BIO-C ION+) coronal (1184.69), middle (997.03), apical (637.26); Group II Subgroup-A AH Plus (864.14) and NanoSeal-S (495.64). Statistical analysis (two-way ANOVA, Tukey's Post Hoc Test) showed significant difference among sealers (p < 0.001) and root canal thirds (p < 0.001).

Conclusion

The results of the study concluded that BIO-C ION + sealer showed maximum dentinal tubule penetration and AH Plus demonstrated maximum push-out bond strength.

Retreatment Strategies for Cases Containing Calcium Silicate-Based Root Canal Sealers: A Comprehensive Review

This review explores the field of retreatment strategies for cases filled with calcium silicate-based root canal sealers. Since the introduction of calcium silicate-based materials in dentistry, calcium silicate-based root canal sealers have become popular among dentists because of their biocompatibility, bioactivity, and sealing ability. Therefore, effective retreatment strategies are indispensable. This article aims to identify the challenges associated with the removal of calcium silicate-based sealers themselves and removal of gutta-percha with the sealers during retreatment, evaluate current techniques and materials, and provide future directions for research in this field. Regarding the strategies of removal of root canal sealers, calcium silicate-based sealers are still relatively new materials for clinicians compared with traditional sealers such as epoxy- or eugenol-based sealers. First, no clinically established solvents have been reported. Second, calcium silicate-based sealers are currently utilized by clinicians in either the cold sealer-based technique or the warm vertical condensation technique. Third, the setting process of calcium silicate-based sealers generates byproducts, primarily calcium hydroxide and secondarily hydroxyapatite, that could interact with dentine. Lastly, there is a lack of clinical studies evaluating the efficacy of retreatment protocols for teeth filled with calcium silicate-based sealers. Therefore, it is important to investigate the chemo-mechanical properties of calcium silicate-based sealers themselves and their reactions to solvents and/or mechanical instruments and identify the interfacial properties of calcium silicate-based sealers with respect to dentine and gutta-percha. In addition, researchers in the clinical field need to actively gather and report data on retreatments of teeth filled with calcium silicate-based sealers.

Filling Material Bond Strength to Dentin Is Positively Influenced by the Agitation of Endodontic Final Irrigating Solutions

Introduction

The final step of irrigation has been considered to of increase the bonding strength of filling material to dentin. This study investigated the impact of three final-step irrigation methods on the endodontic sealer bond strength to dentin by using a micro push-out test.

Materials and Methods

Palatal roots of human maxillary molars were cleaned and shaped and randomly divided in six groups (n=15) according to the final-step irrigation method and the type of root canal sealer used. The solutions used for the final-step irrigation were 17% ethylenediaminetetraacetic acid and 2.5% sodium hypochlorite, which underwent three methods: 1) syringe-needle irrigation/conventional, 2) passive ultrasonic irrigation, and 3) XP-endo Finisher agitation. The root canal sealers used were: EndoSequence BC Sealer, and AH-Plus sealer. Roots were obturated with the single cone technique and then, cross-sectioned in 2-mm-thick slices (3 slices from each root). Push-out test was performed on the sliced specimens (cervical, middle, and apical thirds) with a universal testing machine. Bond strength values were recorded in megapascal (MPa). Subsequently, each specimen was longitudinally split to verify the type of failure. Data analysis was performed using Johnson transformation, three-way analysis of variance, Tukey's post-hoc tests, and the partial Eta squared test.

Results

There were significant differences in bond strength between the sealers [AH: 4.46±2.24 and BC: 3.47±2.19 MPa (P<0.001)]; between final-step irrigation methods [passive ultrasonic irrigation: 4.52±2.25, XP-endo Finisher: 3.93±3.93 and syringe-needle irrigation/conventional: 3.37±2.51 MPa (P<0.001)], and between the root canal thirds represented by the sliced specimens [cervical: 5.45±2.39, middle: 4.14±1.99 and apical: 2.30±1.30 MPa (P<0.001)]. The interaction between the variables had no significance (P>0.05).

Conclusion

Agitation of the final irrigating solution may improve the bonding of the sealer to canal walls. AH-Plus sealer had the highest bond strength. The bond strength reduced significantly towards the apical third.

Comparative Evaluation of Push-out Bond Strength of Three Different Root Canal Sealers: An In Vitro Study

AIM

The aim of this present study was to compare the dislodgement resistance of calcium silicate-based sealer, zinc oxide sealer, and a new sealer combining both zinc oxide and calcium silicate-based sealer in vitro.

MATERIALS AND METHODS

60 single-rooted human teeth were instrumented with F3 Protaper Gold. All endodontic canals were filled using gutta percha cones using the cold lateral condensation technique in combination using one of the mentioned sealers (n = 20 per group). The teeth were divided into three groups: group A consisted of Sealite® Ultra, group B consisted of K-Sealer®, and group C consisted of BioRoot® RC. After 2 months of incubation (37°C, 100% humidity) and after cutting out 2 mm from the most apical portion of the root apex, six slices of 1 mm thickness were generated. Mechanical dislodgement resistance was examined using a universal pressure-testing machine and the push-out bond strength (POBS) was calculated. Specimens were examined under 20× magnification to define the bond failure mode. Statistical analysis was executed using ANOVA, post hoc Turkey test for pairwise comparisons and Kruskal-Wallis tests.

RESULTS

The POBS of BioRoot® was significantly higher than the POBS of the two other sealers with a mean of 10.54 MPa ± 2.10 and 5.73 MPa ± 2.34, respectively (p < 0.001). Sealite® and K-Sealer® showed similar results in the median and coronal part. K-Sealer® revealed highest POBS compared with Sealite® in the apical part (p < 0.05).

CONCLUSION

The POBS of the zinc oxide and calcium silicate-based sealer was significantly lower compared with calcium silicate. Sealite® and K-Sealer® exhibited almost same results. BioRoot showed the highest POBS of all sealers.

CLINICAL SIGNIFICANCE

The current study was needed to evaluate the bond strength of three different cements to dentinal walls, by evaluating their respective POBS in vitro. The findings of this study may provide guidance for the clinician in the selection of an adequate endodontic sealer that guarantees an enhanced adhesive seal between the Gutta-percha and the dentinal canal walls. How to cite this article: Makhlouf MP, El Helou JD, Zogheib CE, et al. Comparative Evaluation of Push-out Bond Strength of Three Different Root Canal Sealers: An In Vitro Study. J Contemp Dent Pract 2024;25(1):15-19.

Effect of Non-thermal Plasma Therapy on Pushout Bond Strength of Epoxy Resin and Tricalcium Silicate-Based Endodontic Sealers

Introduction: The current study aimed to assess the effect of non-thermal plasma (NTP) on the pushout bond strength (PBS) of epoxy resin and tricalcium silicate-based endodontic sealers. Methods: Forty single-canal extracted teeth were decoronated at the coronal region, underwent root canal preparation, and were assigned to four groups (n=10) for the application of AH26 sealer, NTP+AH26 (P-AH26), Endoseal TCS sealer, and NTP+Endoseal TCS sealer (P-TCS). The root canals were sectioned into 1 mm slices, and the PBS value was measured in a universal testing machine. Data were analyzed by the Friedman, Kruskal-Wallis, and Dunn tests (P<0.05). Results: The PBS of TCS and P-TCS groups was not significantly different (P>0.05). The PBS of the P-AH26 group was significantly lower than that of the AH26 group in the middle third (P<0.05). The PBS of the AH26 group was higher than the other groups in all sections. The PBS in the apical third was lower than other sections in all groups (P<0.05). Conclusion: NTP had no significant effect on the PBS of Endoseal TCS. NTP significantly decreased the PBS of AH26 sealer in the middle third but had no significant effect on its bond strength in other sections.

Evaluation of push-out bond strength, dentinal tubule penetration and adhesive pattern of bio-ceramic and epoxy resin-based root canal sealers

INTRODUCTION

Root canal sealing materials play a crucial role in an endodontic procedure by forming a bond between the dentinal walls and the gutta-percha. The current study aims to analyse the dentinal tubule penetration and adhesive pattern, including the push-out bond strength of six commercially available root canal sealers.

METHODOLOGY

Eighty-four mandibular first premolars were split into seven groups (and n = 12), Group 1: Dia-Root, Group 2: One-Fil, Group 3: BioRoot RCS, Group 4: AH Plus, Group 5: CeraSeal, Group 6: iRoot SP, Group 7: GP without sealer (control). Two groups were made, one for dentinal tubule penetration and the other for push-out bond strength; the total sample size was one hundred sixty-eight. Root canal treatment was performed using a method called the crown down technique, and for obturation, the single cone technique was used. A confocal laser scanning microscope (Leica, Microsystem Heidel GmbH, Version 2.00 build 0585, Germany) was used to evaluate dentinal tubule penetration, and Universal Testing Machine was utilised to measure the push-out bond strength (Shimadzu, Japan) using a plunger size of 0.4 mm and speed of 1mm/min. Finally, the adhesive pattern of the sealers was analysed by HIROX digital microscope (KH-7700). Statistical analysis was carried out by a one-way Anova test, Dunnet's T3 test, and Chi-square test.

RESULTS

Highest dentinal tubule penetration was noticed with One-Fil (p<0.05), followed by iRoot SP, CeraSeal, AH Plus, Dia-Root also, the most negligible value was recorded for BioRoot RCS. Meanwhile, BioRoot RCS (p<0.05) demonstrated the greater value of mean push-out bond strength, followed by One-fil, iRoot SP, CeraSeal, AH Plus and Dia-Root. Regarding adhesive pattern, most of the samples were classified as type 3 and type 4 which implies greater sealing ability and better adherence to the dentinal wall. However, BioRoot RCS revealed the most type 4 (p<0.05), followed by AH Plus, One-Fil, CeraSeal and Dia-Root.

CONCLUSION

The highest dentinal tubule penetration was shown by One-Fil compared to other groups. Meanwhile, BioRoot RCS had greater push-out bond strength and more adhesive pattern than other tested materials.

Impact of Heating Exposure on the Micro-Push-Out Bond Strength of Bioceramic Sealers

Introduction

The aim of this study was to evaluate the effect of heating of bioceramic and epoxy resin-based sealers on their micro-push-out bond strength (BS) to root canal dentin.

Methods

After criterial selection, 30 human teeth were decoronated and 1-mm thick slices (n = 60) were obtained perpendicularly along tooth axis, from cervical and middle root thirds, with a diamond disc attached to a cutting machine. In each slice, three 1.0-mm diameter orifices were made. After rinsing with 17% EDTA and 2.5% NaOCl, each orifice was filled with Bio-C Sealer or BioRoot RCS or AH Plus, according to the manufacturers' instructions. After filling, half of the slices (n = 30) were heated at 100°C for 1 min, and the other half were kept at room temperature. After 7 days-controlled storage, micro-push-out test was performed in a Universal Testing Machine. Failures were analyzed using a stereomicroscope. Statistical analysis was performed with One-Way ANOVA and post hoc Tukey (α = 5%) tests.

Results

AH Plus demonstrated higher BS values after heating (p=0.001) when compared to nonheated. The other sealers did not show a statistically significant difference (p > 0.05). When heated, the average BS values for AH Plus were higher than for BioRoot RCS and Bio-C Sealer (p < 0.001). Cohesive failure mode was the most frequent, followed by adhesive and mixed ones.

Conclusion

Heating provided a higher push-out BS to root dentin for AH Plus and did not influence BioRoot RCS or Bio-C sealer.

Influence of long -term thermal cycling and masticatory loading simulation on bond strength of roots filled with epoxy resin and calcium silicate based sealers

BACKGROUND

The aim of this study was to evaluate the effect of thermal and mechanical cyclic aging using a mastication simulator on push-out bond strength of mandibular premolars obturated with AH Plus and BioRoot RCS root canal sealers.

METHODS

With REVO-S files up to SU/0.06 taper, 48 single-rooted premolar teeth were instrumented. The teeth were randomly divided into two main groups (n = 24) based on the two root canal sealers used (AH Plus and BioRoot RCS). All teeth were obturated with h matched-taper single-cone. Each main group was then subdivided into three subgroups (A, B, and C) (n = 8). Group A served as the negative control group (no-thermocycling aging). While groups B and C were subjected to thermal changes in a thermocycler machine (15,000 and 30,000 thermal cycles, respectively), followed by two different dynamic loading periods, 3 × 105 and 6 × 105 in a masticatory simulator with a nominal load of 5 kg at 1.2 Hz which represent roughly 1½ and 3 years of clinical function respectively. 2 mm slice at 3 levels, apical, middle, and coronal, to obtain 3 sections were prepared and subjected to push-out test using a universal testing machine. Statistical analysis was performed using analysis of variance (ANOVA) followed by a Tukey post hoc comparisons test and an independent T-test. A significance level of 5% was used.

RESULTS

After thermal-mechanical cyclic aging, the two root canal sealers showed a significantly decreased in push-out bond strength (p < 0.05), however, AH Plus had significantly higher bond strength values than BioRoot RCS after cycling aging.

CONCLUSIONS

It could be concluded that thermal-mechanical cyclic aging had a significant impact on the outcome of the dislodgment resistance of AH Plus and BioRoot RCS.

Effect of Photodynamic Therapy on the Pushout Bond Strength of Resin-Based and Calcium Silicate-Based Endodontic Sealers

Introduction: This study aimed to assess the effect of photodynamic therapy (PDT) on the pushout bond strength (PBS) of resin-based and calcium silicate-based endodontic sealers. Methods: Forty single-canal teeth were assigned to four groups. After root canal preparation by the crown-down technique and smear layer removal, groups 1 and 2 served as the control group, and groups 3 and 4 underwent PDT by using a low-level diode laser as the light source and methylene blue as the photosensitizer (MB). The root canals in groups 1 and 3 were filled with AH26 sealer while the root canals in groups 2 and 4 were filled with Endoseal TCS. The samples were sectioned at 4, 8, and 12 mm from the apex tip (1mm thick slices). The PBS test was performed, and the mode of failure was determined in the coronal, middle, and apical thirds. The data were analyzed by the Kruskal-Wallis, Friedman, and Dunn tests. Results: No significant difference was noted in the PBS of resin-based and calcium silicate-based sealers in the apical, middle, or coronal thirds in the application of PDT (P>0.05). The PBS of AH26 was significantly higher than that of Endoseal TCS (P<0.05). Cohesive failure was the dominant mode of failure in the AH26 groups, while mixed failure was the dominant failure mode in the Endoseal TCS groups. Conclusion: PDT had no significant effect on the PBS of resin-based and calcium silicate-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.

Effect of endodontic sealers on push-out bond strength of CAD-CAM or prefabricated fiber glass posts

This study aimed to evaluate the effect of endodontic sealer (ES) on bond strength (BS) of prefabricated or milled-CAD-CAM (computer-aided design and computer-aided manufacturing) glass-fiber-posts (GFP). Canals of 90 single-rooted teeth were prepared for filling by the single-cone technique with gutta-percha and one of the following ES: AH Plus (epoxy resin), Endofill (zinc-oxide and eugenol), and Bio-C Sealer (calcium-silicate). After post-space preparation, tooth-specimens were equally divided in half according to type of GFP to be used. In the half to receive milled-CAD-CAM posts, tooth specimens were molded with acrylic resin to obtain replicas. These were scanned to enable the laboratory to produce the milled-CAD-CAM GFPs (Fiber CAD Lab, Angelus) by the subtractive technique. The other half of samples received prefabricated GFPs (Exacto, Angelus) (n=15). The GFPs were cemented with dual-cure resin cement (Panavia F2.0, Kuraray). Each root was sectioned into two slices per root region (cervical, middle, apical) that were subjected to the push-out BS test, in a universal testing machine. Failure mode (FM) was classified by scores. The BS data were submitted to generalized linear model analyses, while FM was analyzed using the chi-square test (a=0.05). BS showed no significant difference among the three ES (p > 0.05). BS was significantly higher for prefabricated (mean 10.84 MPa) versus milled-CAD-CAM GFPs (mean 6.94 MPa) (p <0.0001), irrespective of ES. The majority showed mixed failures. It could be concluded that type of ES did not affect BS of GFPs to dentin, and prefabricated-GFPs had higher bond-strength than customized-milled-CAD-CAM GFPs.

Dentinal Tubule Penetrability and Bond Strength of Two Novel Calcium Silicate-Based Root Canal Sealers

BACKGROUND

Once the chemo-mechanical preparation of root canals is finished, achieving a complete seal of the root canal system becomes crucial in determining the long-term success of endodontic treatment. The important goals of root canal obturation are to minimize leakage and achieve an adequate seal. Thus, a material that possesses satisfactory mechanical characteristics, is biocompatible, and has the ability to penetrate the dentine tubules adequately is needed.

AIM

This study aimed to compare the penetrability and bond strength between two calcium silicate-based sealers and an epoxy resin-based sealer, as well as examine the relationship between penetrability and bond strength for the different sealers.

METHOD AND MATERIALS

Thirty-nine recently extracted single-rooted human premolar teeth were instrumented and divided evenly into three groups (n = 13), according to the sealer used for obturation: AH Plus Jet, EndoSequence, and AH Plus Bioceramic Sealer. Three teeth (30 slices) were randomly selected out of each for analysis using confocal laser scanning microscopy to assess penetrability. The remaining ten teeth (90 slices) in each group were subject to push-out tests using a universal testing machine. All teeth were sectioned into nine transverse slices of 0.9 mm thickness for their respective tests (apical, middle, coronal).

RESULTS

AH Plus Jet exhibited significantly lower penetrability and significantly higher bond strength compared to EndoSequence BC sealer (p = 0.002) and AH Plus Bioceramic Sealer (p = 0.006). There was no significant difference between EndoSequence BC sealer and AH Plus Bioceramic Sealer in terms of either penetrability or bond strength. No correlation was found between penetrability and bond strength.

CONCLUSIONS

Within the limitation of this study and regardless of the location in the canal, the bioceramic based root canal sealers appeared to perform better than the epoxy resin-based sealer in terms of dentinal penetration rate. Further studies are required to compare other biomechanical properties of bioceramic sealers including setting characteristics and bacterial leakage.

Efficacy of Shock Wave-Enhanced Emission Photoacoustic Streaming (SWEEPS) in the Removal of Different Combinations of Sealers Used with Two Obturation Techniques: A Micro-CT Study

This study sought to evaluate the efficacy of SWEEPS in the removal of epoxy-resin-based and calcium-silicate-containing endodontic sealer combined with single-cone and carrier-based obturation techniques through a micro-CT analysis. Seventy-six single-rooted extracted human teeth with single root canal were instrumented with Reciproc instruments. Specimens were randomly divided into four groups (n = 19) according to the root canal filling material and obturation technique: (1) AH Plus sealer + Reciproc gutta-percha, (2) TotalFill BC sealer + TotalFill BC Points, (3) AH Plus sealer + Guttafusion obturator, and (4) MTA Fillapex + Guttafusion obturator. All specimens were re-treated one week later using Reciproc instruments. Following re-treatment, root canals were additionally irrigated using the Auto SWEEPS modality. The differences in the root canal filling remnants were analyzed by micro-CT scanning of each tooth after root canal obturation, after re-treatment, and after additional SWEEPS treatment. Statistical analysis was performed using an analysis of variance (p < 0.05). The additional treatment with SWEEPS significantly reduced the volume of the root canal filling materials in all experimental groups compared to the removal of root canal filling using only reciprocating instruments (p < 0.05). However, the root canal filling was not removed completely from any of the samples. SWEEPS can be used to enhance the removal of both epoxy-resin-based and calcium-silicate-containing sealers, in combination with single-cone and carrier-based obturation techniques.

Dislodgment Resistance, Adhesive Pattern, and Dentinal Tubule Penetration of a Novel Experimental Algin Biopolymer-Incorporated Bioceramic-Based Root Canal Sealer

The currently available bioceramic-based sealers still demonstrate low bond strength with a poor seal in root canal despite desirable biological properties. Hence, the present study aimed to determine the dislodgment resistance, adhesive pattern, and dentinal tubule penetration of a novel experimental algin-incorporated bioactive glass 58S calcium silicate-based (Bio-G) sealer and compared it with commercialised bioceramic-based sealers. A total of 112 lower premolars were instrumented to size 30. Four groups (n = 16) were assigned for the dislodgment resistance test: control, gutta-percha + Bio-G, gutta-percha + BioRoot RCS, and gutta-percha + iRoot SP, with exclusion of the control group in adhesive pattern and dentinal tubule penetration tests. Obturation was done, and teeth were placed in an incubator to allow sealer setting. For the dentinal tubule penetration test, sealers were mixed with 0.1% of rhodamine B dye. Subsequently, teeth were cut into a 1 mm-thick cross section at 5 mm and 10 mm levels from the root apex, respectively. Push-out bond strength, adhesive pattern, and dentinal tubule penetration tests were performed. Bio-G showed the highest mean push-out bond strength (p < 0.05), while iRoot SP showed the greatest sealer penetration (p < 0.05). Bio-G demonstrated more favourable adhesive patterns. No significant association was noted between dislodgment resistance and dentinal tubule penetration (p > 0.05).

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.

Effect of a bioactive glass-based root canal sealer on root fracture resistance ability

Background/purpose

The root fracture resistance of endodontically treated teeth is decreased significantly, and it is more likely to fracture. This study aimed to evaluate the effect of a novel root canal sealer based on bioactive glass (BG) on root fracture resistance and explore its mechanism.

Materials and methods

The BG-based root canal sealer (BG Sealer) was prepared by mixing a kind of bioactive glass (10.8% P₂O₅, 54.2% SiO₂, 35% CaO, mol.%, named PSC), zirconia (ZrO₂) powder, sodium alginate (SA) and phosphate solution (PS). A pH meter was used to measure the pH of simulated body fluid (SBF) after immersion with BG Sealer at different time. After preparing the samples of BG sealer with a diameter of 4 mm and a height of 6 mm, the compressive strength was tested by a universal testing machine. The scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were used to detect and analyze the mineral status of root canal systems filled with BG Sealer. The push out test was used to measure the push out bond strength of BG Sealer. The fracture resistance of root canals filled with BG Sealer was detected by the compressive loading test. Bioceramic root canal sealer iRoot SP was set as the control group.

Results

(1) Physicochemical properties: The pH value of SBF immersed with BG Sealer increased slightly up to 7.68, while the pH of SBF immersed with iRoot SP increased to 12.08. The compressive strength of the novel BG Sealer was 4.62 ± 1.70 MPa, which was lower than that of iRoot SP (P < 0.05). (2) Mineralization: The hydroxyapatite layers were observed on the surface of BG Sealer and iRoot SP after being immersed in SBF for 4 weeks. BG Sealer and iRoot SP were both able to penetrate into the dentin tubules, duplicate the morphology of root canals well, and form a layer of hydroxyapatite. (3) Adhesion to dentin: There was no significant difference between the push out bond strength of the novel BG Sealer and iRoot SP (P > 0.05). (4) Fracture resistance: After immersion in SBF for 4 weeks, the fracture resistance of roots filled with BG Sealer and iRoot SP was 454.16 ± 155.39 N and 445.50 ± 164.73 N, respectively, both of which were not statistically different from that of the roots unprepared and unfilled (394.07 ± 62.12 N) (P > 0.05), whereas higher than that of the roots prepared and unfilled (235.36 ± 83.80 N) (P < 0.05).

Conclusion

The novel BG Sealer has good adhesion to the root dentin, can penetrate into the dentin tubules to generate minerals, and meanwhile can improve the fracture resistance of the roots after root canal treatment. It is expected to be a bioactive root canal sealer with good clinical application prospects.

Efficacy of Reciprocating Instruments in Retreatment of Bioactive and Resin-Based Root Canal Sealers

Objective

To compare the effectiveness of reciprocating instruments in removing gutta-percha and bioactive-based (BioRoot RCS and MTA Fillapex) and epoxy resin-based (AH Plus) sealers from root canals based on filling residues and the time required for root canal revision.

Material and methods

Root canals of 90 teeth were instrumented with Reciproc R40. All root canals were obturated using the single-cone technique with Reciproc R40 gutta-percha and with one of the selected sealers. Samples with oval, straight canals were used and randomly divided into three groups: (i) filled with AH Plus sealer and gutta-percha (n=30); (ii) filled with MTA Fillapex and gutta-percha (n=30); (iii) filled with BioRoot RCS and gutta-percha (n=30). Each group was divided into two subgroups (n=15) according to the retreatment instrument used (Reciproc M-Wire R25/R40 or Reciproc blue RB25/RB40). Root canals were longitudinally split and analyzed with a stereomicroscope at 15 × magnifications in the coronal, middle, and apical third. Computational analyses were performed with the Image J software. Data were compared using the Kruskal-Wallis test and Mann-Whitney U test.

Results

While no statistically significant differences in the residual material surface were found for Reciproc Blue, Reciproc M-Wire showed significantly higher residual material surface for AH Plus and MTA Fillapex compared to BioRoot RCS. For AH plus. Residual material surface was significantly lower for Reciproc Blue than for Reciproc M-Wire. In contrast, BioRoot RCS showed a significantly higher residual material surface for Reciproc Blue.

Conclusions

Calcium silicate-containing sealers were more retrievable compared to AH Plus, with fewer sealer remnants and shorter retreatment time. Retreatment with Reciproc M-Wire instruments was superior to Reciproc blue instruments in retreatment of BioRoot RCS. However, none of the sealers were removed completely.

Evaluation of Bond Strength of Four Different Root Canal Sealers

The purposes of the study were to evaluate the influence of the sealer’s chemical composition on the interfacial strength between root canal dentin and root filling material, for two different classes of endodontic sealers, and to assess their failure modes. Methods: Forty extracted single-rooted teeth were randomly divided into four groups using the following endodontic sealers: RealSeal SE and Resilon (RSSE); EndoSequence BC sealer and BC Point (EBCS); Endoseal MTA and gutta-percha (EDS); Bioroot RCS and gutta-percha (BRS). Teeth were embedded in acrylic resin, and the roots were sectioned horizontally into 1 mm slices. For each slice, the perimeter was measured. A push-out test was performed using an Instron universal testing machine. For each sample, bond strength was calculated. Specimens were examined by SEM investigation in order to analyze the dentin−sealer−core interface. Results were assessed using analysis of variance (ANOVA) and Tukey and Bonferroni test. Results: Statistical analysis revealed that EDS and gutta-percha had significantly higher resistance to dislodgement compared to the other three groups (p < 0.05). EBCS and BC Point showed significantly greater push-out bond strength values compared to RSSE and Resilon (p < 0.05). Conclusions: Bioceramic endodontic sealers showed a higher bond strength to root dentin than methacrylate resin-based endodontic sealer.

Shear Bond Strength of Ah26 to Human Dentin Treated with Dimethyl Sulfoxide (Dmso)

The purpose of this study was to examine the bond strength of AH26 to human coronal dentin exposed to DMSO. A total of 70 dentin specimens were equally divided into two groups. Each dentin surface was pre-treated with 2 mL of 2.5% NaOCl, 3 mL of EDTA 17%, and distilled water. One group was finally rinsed with 50% DMSO. Following the AH26 application, the bond strength was tested by subjecting the samples to a shear load at a crosshead speed of 0.5 mm/min using universal testing equipment. The results according to paired samples t-test indicated that there was a statistically insignificant difference between the two groups. Therefore, DMSO had no effect on the bond strength of AH26 root sealer to dentin.

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.

The effect of four different intracanal medicaments on the push-out bond strength of root canal sealers

This study aimed to compare the effect of 4 different intracanal medicaments on the push-out bond strength of two sealers (AH Plus and MTA Fillapex). 100 single-rooted extracted premolar teeth were divided into 5 groups, with 20 samples in each group, one group being the control group. After cleaning and shaping procedures, the canals were filled with 4 different medicaments: calcium hydroxide, tri-antibiotic paste (TAP), Metapex, or Chlorhexidine (2%) gel for 2 weeks. Following this, the medicaments were rinsed away, and the samples in those sub-groups were obturated with gutta-percha/AH Plus or MTA Fillapex sealers. After 2 weeks of incubation, a 2-mm-thick middle section from each root was evaluated to test push-out strength. The obtained data were tabulated, and appropriate statistical analysis was performed (two-way ANOVA and LSD test). When comparing the average values, the bond strength values of AH Plus were significantly higher than those of MTA Fillapex (p<0.05) in all medicament groups. Based on the findings, we concluded that AH Plus had comparatively higher bond strength than MTA Fillapex. We also observed that AH Plus had higher bond strength in the presence of calcium hydroxide, whereas MTA Fillapex in the presence of Chlorhexidine. A comparison of the push-out bond strength shows that irrespective of the root canal segment or the final irrigant used, AH Plus showed higher values among all groups. The limitation of the current study was that the effect of TAP on the bond strength of endodontic sealers was not negative.

Comparative evaluation of push-out bond strength of bioceramic and epoxy sealers after using various final irrigants: An in vitro study

Aim:

The aim of the study is to compare the push-out bond strength of bioceramic and epoxy sealers after using various final irrigants.

Materials and Methods:

Hundred single-rooted teeth were divided into two groups (n = 50) according to the sealer used: Group A: Bio C (bioceramic sealer), Group B: Dia-Proseal (epoxy sealer). Each group was subdivided into five subgroups (n = 10) according to the final irrigation protocol: Group A1 and B1 – 5% glycolic acid (GA), Group A2 and B2 – 17% GA, Group A3 and B3 – 0.2% chitosan, Group A4 and B4 – 17% ethylenediaminetetraacetic acid, and Group A5 and B5 – 0.9% saline. Samples were obturated in combination with one of the mentioned sealers and were allowed to set for 1 week. Two horizontal slices were obtained from each sample and subjected to push-out test.

Statistical Analysis:

The data were statistically analyzed using two-way ANOVA and independent Student's t-test.

Results:

Both the sealers exhibited higher push-out bond strength after treatment with GA with no significant difference between 5% and 17% GA. Bio C sealer with GA as final irrigant showed higher bond strength than Dia-Proseal (P < 0.05).

Conclusion:

The push-out bond strength of the sealer was significantly affected by the final irrigation solution used. The highest push-out bond strength was seen with Bio C sealer after treatment with GA with no significant difference between 5% and 17% GA.

Physico-Chemical Properties of Calcium-Silicate vs. Resin Based Sealers-A Systematic Review and Meta-Analysis of Laboratory-Based Studies

INTRODUCTION

The aim of this systematic review is to analyse the effect of physico-chemical properties of calcium silicate-based sealers in comparison to epoxy resin sealers in permanent teeth using a single-cone obturation technique.

METHODS

The study was conducted according to the guidelines of Cochrane Handbook for Systematic Reviews of Interventions and Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) statement. Literature search was performed using the PubMed/MEDLINE, Cochrane Central Register of Controlled Trials, Web of Science, DOAJ, Open Gray with no language restrictions until October 2020. Two reviewers assessed the studies for eligibility. Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) was carried out to assess the evidence. Meta-analysis of the pooled data with subgroups was performed using the RevMan software (p < 0.05).

RESULTS

Results from the 28 included studies showed that the mean difference in adaptation to root canal walls (marginal adaptation, interfacial gaps and void volume) for both sealers were non-significant. However, void volume values showed a significant mean difference (p < 0.00001) favouring the calcium silicate-based sealers. The pooled meta-analysis reported statistically significant differences for apical microleakage (p = 0.0007) whilst there were non-significant mean differences for fracture resistance (p = 0.09) and push-out bond strength (p = 0.63). The heterogeneity among the included studies was 97% (I²).

CONCLUSIONS

Within the limitations of this review, calcium silicate-based sealers demonstrated a similar or superior performance in comparison to resin-based sealers in terms of the physico-chemical properties.

Effect of Sodium Hypochlorite Concentration in Continuous Chelation on Dislodgement Resistance of an Epoxy Resin and Hydraulic Calcium Silicate Sealer

The conditioning of the root canal wall during chemo-mechanical root canal treatment differentially affects the adhesion of root canal sealers. This investigation evaluated the impact of sodium hypochlorite (NaOCl) concentration as used in a root canal irrigation concept called continuous chelation, with 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) contained in the NaOCl solution that is applied. Fourier-transform infrared spectra of the dentinal wall were gathered. The consequential effects on push-out bond strength of an epoxy resin (AH Plus) versus a hydraulic CaSi sealer (BioRoot RCS) were assessed. Single-rooted extracted human teeth were used and irrigated with pure NaOCl at a concentration of 0% (physiological saline), 2.5%, or 5.25%. Dual Rinse HEDP (9%) was added to the solutions, or not added for further control. Pure NaOCl solutions caused a decrease in the amide III: phosphate ratios, which was counter-acted by the addition of HEDP. It was observed that the adhesion of the epoxy resin sealer under investigation was negatively affected by this NaOCl deproteinization of the canal wall in a dose-dependent manner, while the opposite was observed with the CaSi sealer. HEDP when used in conjunction with NaOCl was beneficial for the adhesion of both sealers.

A micro-computed tomographic evaluation of retreatability of BioRoot RCS in comparison with AH Plus

This study compared the retreatability of filling material from canals filled with BioRoot RCS (Septodont, Saint-Maur-des-Fosses, France) and AH Plus (Dentsply DeTrey, Konstanz, Germany) combined with gutta-percha using micro-computed tomography for evaluation. Thirty-four mandibular premolars were divided into two groups according to the sealer used. Thirty days after obturation, canals were retreated with a ProTaper Universal retreatment system (Dentsply Maillefer, Ballaigues, Switzerland) followed by passive ultrasonic irrigation (PUI). The time taken for retreatment was recorded. The roots were scanned after obturation, after retreatment and after PUI. Data were analysed using the Mann-Whitney and Wilcoxon tests. Canals filled with BioRoot RCS exhibited significantly less remaining filling material than canals filled with AH Plus (P < 0.05). The addition of PUI resulted in a significant decrease in the residual material in both groups (P < 0.05). A significantly shorter retreatment time was reported for the AH Plus group than the BioRoot RCS group (P < 0.05).

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.

Effects of radiation therapy on the dislocation resistance of root canal sealers applied to dentin and the sealer-dentin interface: a pilot study

Objectives

This study evaluated and compared the effects of radiation therapy on the dislocation resistance of AH Plus and BioRoot RCS applied to dentin and the sealer-dentin interface.

Materials and Methods

Thirty single-rooted teeth were randomly assigned to 2 groups (n = 15 each): AH Plus (Dentsply DeTrey) and BioRoot RCS (Septodont). Each group was subdivided into control and experimental groups. The experimental group was subjected to a total radiation dose of 60 Gy. The root canals of all samples were cleaned, shaped, and obturated using the single-cone technique. Dentin slices (1 mm) were sectioned from each root third for the push-out test and scanning electron microscopy (SEM) was done to examine the sealer-dentin interface. The failure mode was determined using stereomicroscopy. Bond strength data were analyzed by the independent t-test, 1-way analysis of variance, and the Tukey post hoc test (α = 0.05).

Results

Significantly lower bond strength was observed in irradiated teeth than non-irradiated teeth in the AH Plus group (p < 0.05). The BioRoot RCS group showed no significant reduction in bond strength after irradiation (p > 0.05) and showed a higher post-irradiation bond strength (209.92 ± 172.26 MPa) than the AH Plus group. SEM revealed slightly larger gap-containing regions in irradiated specimens from both groups.

Conclusions

The dislocation resistance of BioRoot RCS was not significantly changed by irradiation and was higher than that of AH Plus. BioRoot RCS may be the sealer of choice for root canal treatment in patients undergoing radiation therapy.

Push-Out Bond Strength, Characterization, and Ion Release of Premixed and Powder-Liquid Bioceramic Sealers with or without Gutta-Percha

OBJECTIVE

To evaluate the push-out bond strength of premixed and powder-liquid bioceramic sealers with or without gutta-percha (GP) cone.

MATERIALS AND METHODS

Radicular dentin samples were prepared from 80 single-rooted human teeth. After root canal preparation using ProTaper® and irrigation with NaOCl and EDTA, teeth were divided according to the root canal sealer (n = 20): AH Plus®, EndoSequence® BC Sealer™, ProRoot® Endo Sealer, and BioRoot™ RCS. Samples were randomly divided into two subgroups (n = 10): GP-S: root canal filling using the single-cone technique, or S: filling with only sealer. Specimens were kept at 37°C and 100% humidity in calcium-free PBS for 30 days. The push-out bond strength was measured in MPa. Fractured specimens were observed at 25x to evaluate the type of failure. pH and calcium ion release were measured at different experimental periods. Raman and SEM-EDAX analyses were performed for root canal sealers. Data were analysed using three-way analysis of variance (ANOVA) and post hoc Tukey test at a significance of P < 0.05.

RESULTS

Push-out bond strength was greater for samples obturated with only sealers (S) than samples obturated with the single-cone technique (GP-S) (P < 0.05). BioRoot™ RCS had greater bond strength than EndoSequence® BC Sealer™. Adhesive failures between cement and gutta-percha cone (87.5%) were predominant in the GP-S. Cohesive failures were predominant for S (80%). BioRoot™ RCS and ProRoot® ES presented higher alkalinization potential than the premixed sealer (EndoSequence® BC Sealer™). Powder-liquid bioceramic sealers (BioRoot™ RCS and ProRoot® ES) released the highest cumulative amount of calcium (28.46 mg/L and 20.05 mg/L).

CONCLUSION

Push-out test without gutta-percha cone presents higher bond strength for bioceramic sealers. Powder-liquid calcium silicate-based sealers present greater bioactivity related to alkalinization potential and calcium ion release.

Physicochemical properties and cytocompatibility of newly developed calcium silicate-based sealers

The purpose of this study was to compare the physical properties and cytocompatibility of contemporary calcium silicate-based sealers. Four calcium silicate-based sealers (BrightEndo MTA sealer, CeraSeal, EndoSeal TCS and One-Fil) were compared to an epoxy resin-based sealer (AH Plus). Flow, setting time, radiopacity and dimensional change were evaluated according to ISO 6876 standards. Cytotoxicity on human periodontal ligament fibroblast (hPDLF) cells was compared for biological properties using MTT assay. The surface of the sealer was analysed using scanning electron microscopy to evaluate cell attachment. Flow and radiopacity of all sealers met ISO standards, while setting time and dimensional stability did not meet the ISO standards. Calcium silicate-based sealers showed favourable cytocompatibility, and hPDLF cells were well attached to the calcium silicate-based sealers. Calcium silicate-based sealers have clinically acceptable flow and radiopacity, and cytocompatibility. However, these sealers had longer setting time and higher dimensional change than those required by ISO 6876.

Effects of Both Fiber Post/Core Resin Construction System and Root Canal Sealer on the Material Interface in Deep Areas of Root Canal

This study aimed to examine the resin polymerization of a fiber post/core resin construction system and the interface between resin and root canal sealers, which are important for root canal sealing. We used the i-TFC Luminus fiber post and i-TFC Luminus LC flow (i-TFC-L), the GC fiber post and Unifil Core EM (GCF), and the FiberKor post and Build-It FR (FKP) as core construction systems, and Nishika Canal Sealer BG (CS-BG), Metaseal Soft (META), and Nishika Canal Sealer EN (CS-EN) as sealers. The light transmission of fiber posts (n = 5), the polymerization of core resin (n = 5), and the adhesion between the sealer and core resin (n = 10) were evaluated. The i-TFC Luminus fiber post light transmission was significantly higher than that of other posts. Without shielding, i-TFC-L showed a significantly greater amount of polymerized resin than the other systems. With shielding, although i-TFC-L showed a significantly greater amount of polymerized resin immediately after light irradiation, polymerized resin was significantly greater in GCF and FKP after 10 min. All systems adhered to CS-BG and META but not to CS-EN. These results indicate that resin polymerization in the cavity differs among fiber post/core resin construction systems and that the adhesion of the resin and sealer depends on the property of the sealer.

Calcium silicate-based root canal sealers: a literature review

Epoxy resin-based sealers are currently widely used, and several studies have considered AH Plus to be the gold-standard sealer. However, it still has limitations, including possible mutagenicity, cytotoxicity, inflammatory response, and hydrophobicity. Drawing upon the advantages of mineral trioxide aggregate, calcium silicate-based sealers were introduced with high levels of biocompatibility and hydrophilicity. Because of the hydrophilic environment in root canals, water resorption and solubility of root canal sealers are important factors contributing to their stability. Sealers displaying lower microleakage and stronger push-out bond strength are also needed to endure the dynamic tooth environment. Although the physical properties of calcium silicate-based sealers meet International Organization for Standardization recommendations, and they have consistently reported to be biocompatible, they have not overcome conventional resin-based sealers in actual practice. Therefore, further studies aiming to improve the physical properties of calcium silicate-based sealers are needed.

Dislodgement resistance and adhesive pattern of different endodontic sealers to dentine wall after artificial ageing: an in-vitro study

To compare the dislodgement resistance and the adhesive pattern of four different endodontic sealers to root dentine walls. Ninety lower premolars were assigned to five groups (n = 18), Group 1: no sealer (control); Group 2: EndoRez (ERZ); Group 3: Sealapex (SPX); Group 4: EndoSeal MTA (ESA) and Group 5: BioRoot RCS (BRS). They were instrumented up to size 30 taper 0.06 and obturated using single cone technique with matched-taper gutta-percha cones and one of the mentioned sealers. Six teeth from each group were then randomly subjected to 100, 1000 and 10,000 thermocycles, respectively. 1 mm slice of mid root region, measuring 6 mm from the apical foramen was prepared and subjected to push-out test under a Universal Testing Machine. Adhesive patterns of sealers were assessed using a stereomicroscope at 20 × magnification and classified using a new system. Statistical analyses were performed using two-way ANOVA, complemented by Tukey HSD and Chi-square tests. ESA and BRS showed significantly higher (p < 0.05) push-out bond strength, followed by SPX, ERZ and lastly the control, but no significant difference was noted between ESA and BRS (p > 0.05) at 100, 1000 and 10,000 thermocycles, respectively. Both ESA and BRS exhibited a significant higher rate (p < 0.05) of Type 3 and Type 4 adhesive patterns as the thermocycles increased. ESA and BRS demonstrated higher bond strength and better adhesive pattern to root dentine wall than SPX and ERZ, especially after artificial ageing.

Does Caffeic Acid Phenethyl Ester as an Irrigation Solution Increase the Adhesive Quality of Root Canal Sealer?

Aim:

To evaluate the effect of the caffeic acid phenethyl ester (CAPE) as a root canal irrigation agent on the push-out bond strength of the AH-Plus sealer.

Materials and Methods:

A total of 75 single-rooted teeth were decoronated and were randomly divided into 5 groups of 15 roots for irrigation protocols: Group NaOCl: 5.25 percent NaOCl; Group CAPE: 0.5 percent CAPE; Group NaOCl + ethylenediaminetetraacetic acid (EDTA): 5.25 percent NaOCl-17 percent EDTA; Group NaOCl + CAPE: 5.25 percent NaOCl-0.5 percent CAPE; and Group CAPE + EDTA: 0.5 percent CAPE-17 percent EDTA (for 3 min each group). All root canals were then obturated and 1-mm-thick horizontal slices were obtained from different root thirds of the root canal (coronal, middle, and apical, respectively). The groups were challenged with push-out tests. Modes of failure were determined under a stereomicroscope.

Results:

The CAPE-EDTA-treated group presented the highest mean bond strength in the coronal region of root dentin ( P < .05). The CAPE-treated group had a higher mean bond strength than the NaOCl-treated group ( P < .05). The mixed mode of failure was most predominant in all groups.

Conclusion:

Under the presented in vitro conditions, CAPE alone or in combination with EDTA or NaOCl demonstrated a positive effect that increased the push-out bond strength of the AH-Plus sealer to root dentin.

Effect of Distinctive Moisture Conditions on Push-out Bond Strength of Three Root Canal Sealers-An In-Vitro Study

Objective:

Endodontic sealer should adhere to both dentin and the core filling material but the moisture conditions of the canals affect the adhesive properties of the sealer. An ideal sealer with perfect moisture conditions will lead to greater strength of the restored tooth, which may provide greater resistance to tooth fracture and clinical longevity of an endodontically treated tooth. The aim of this study was to evaluate the effect of moisture conditions on the push-out bond strength of three root canal sealers: AH Plus^® (Dentsply-Tulsa Dental, Tulsa, OK), Epiphany (Pentron Clinical Technologies, Wallingford, CT), and GuttaFlow (Coltene/Whaledent, Altstatten, Switzerland).

Materials and Methods:

A total of 120 single-rooted, non-carious teeth were collected for the study and were stored in normal saline. The root canals were prepared using step-back technique. Teeth were divided into four groups based on type of drying procedure used and further subdivided into three subgroups based on the type of sealer used. The samples were cut horizontally to produce slices and then tested for push-out bond strength using Universal Testing Machine (Servo Series 50 kN; P S I Sales Private Limited, New Delhi, India). The specimens were examined for mode of fracture under magnification and the results were analyzed statistically.

Results:

Distinctive moisture conditions for all sealers were observed and the highest strength of AH Plus^® was evaluated under moist condition, Epiphany under dry condition, and GuttaFlow under normal condition, respectively.

Conclusion:

Distinctive moisture conditions affect the push-out bond strength of the sealers.

Duration of Immersion and Type of Immersion Solution Distort the Outcome of Push-Out Bond Strength Testing Protocols

This study aimed to investigate the influence of immersion duration and the type of immersion solution on the outcome of push-out bond strength (POBS) tests. Root canals of 120 straight single-rooted teeth were instrumented to a diameter of 1.5 mm and irrigated with 5 mL of 3% NaOCl. Four horizontal slices with a thickness of 1 mm were cut, representing the mid-portion of the root. The specimens (n = 480) were irrigated with 17% ethylenediaminetetraacetic acid(EDTA) for 60 seconds, then twice with distilled water (DW) for 30 s each. The canals were filled with either AH Plus (Dentsply Sirona, Konstanz, Germany) or BioRoot RCS (Septodont, St. Maur-des-Fossés, France) (n = 240). Separated into four groups per type of sealer (n = 60), the specimens were incubated at 37 °C covered with gauze moistened in DW or phosphate-buffered saline (PBS) for either one or eight weeks. Dislodgement resistance was measured and POBS was calculated. Statistical analysis was performed using the analysis of variance (ANOVA) test and the Student-Newman-Keuls test (p = 0.05). AH Plus showed higher POBS when stored in PBS compared to DW, irrespective of the incubation period (p < 0.05). BioRoot RCS displayed higher POBS when stored in DW compared to PBS after eight weeks of incubation (p < 0.05). No difference was found after one week of incubation (p > 0.05). Irrespective of the sealer or the immersion solution, POBS decreased from one week to eight weeks (p < 0.05). Mixed failure modes were found in all groups irrespective of sealer, immersion medium, or immersion period. POBS decreased after a longer incubation time in both immersion solutions. Duration of immersion and the type of immersion solution had a significant impact on the outcome of the POBS testing protocol.

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.