The effect of natural reducing agents on push-out bond strength of AH plus and BioRoot RCS to sodium hypochlorite treated root dentin

Comparative evaluation of push-out bond strength and mode of failure of three different obturating materials: An in vitro study

Aim

This research aimed to assess the push-out bond strength (PBS) to dentin of three distinct obturation materials inside the root canal and identify the failure mechanism.

Materials and Methods

The research used 30 undamaged human mandibular premolars. The specimens were randomly assigned to three groups, each employing a different sealer (n = 10). Group 1 used AH Plus sealer, Group 2 used GuttaFlow-2 sealer, and Group 3 used bioceramic sealer (CeraSeal). The obturation procedure was performed utilizing the single-cone method with gutta-percha. The specimens were divided into sections and loaded using a universal testing machine. Following PBS testing, every sample underwent a stereomicroscope examination, and the specific failure mechanism was documented.

Results

The average PBS was greatest for AH Plus, followed by CeraSeal and Guttaflow-2. Notable disparities existed between the coronal and apical levels.

Conclusion

AH Plus exhibited superior PBS qualities to root dentin compared to other sealers.

Effect of collagen cross-linking agents on the depth of penetration of bioceramic sealer and release of hydroxyproline: An in vitro study

Context

During endodontic treatment, sealers seal off dentinal tubules and prevent microbial attack. Bioceramic sealers have excellent bioactivity, but its high alkalinity is found to have detrimental effects on radicular collagen. Collagen cross linkers have the ability to chemically modify collagen and can prevent the detrimental effects of the sealer.

Aim

This research was aimed to assess the effect of collagen cross-linking agents on the integrity of radicular collagen matrix and depth of penetration of sealer.

Materials and Methods

Mandibular premolars (n = 48) were taken. Teeth were decoronated; canals were prepared till ProTaper size F2 and were irrigated with 5 mL of 2.5% NaOCl, followed by 3 mL of 17% ethylenediaminetetraacetic acid between instrumentation and finally rinsed with saline following which teeth were divided into three groups based on the surface treatments: Group 1: 6.5% proanthocyanin (PA), Group 2: chlorhexidine (CHX), and Group 3: saline. Teeth were obturated using gutta-percha and bioceramic sealer and stored in artificial saliva. Hydroxyproline (HYP) release was assessed after 14 and 21 days using spectrophotometer. Sealer penetration was assessed using the scanning electron microscope.

Statistical Analysis

Wilcoxon signed-rank test and Kruskal-Wallis test for release of HYP and paired t-test and ANOVA for sealer penetration were performed.

Results

Significantly lower release of HYP was seen in proanthocyanin-treated group. Sealer penetration was better for both the proanthocyanin- and CHX-treated groups when compared to saline.

Conclusion

Surface treatment with collagen cross-linkers caused a decrease in the amount of HYP released, indicating lesser degradation of collagen. Sealer penetration was better due to the removal of smear layer following the surface treatments.

Canal disinfection using photo-chemically activated micro-bubble emulsion, Emblica officinalis, and Nd: YAP laser on smear layer and push-out bond strength of resin-based root canal sealer to the radicular dentin

AIMS

Evaluation of the effects of the latest root canal disinfectants i.e., Micro-bubble emulsion (MBE), Neodymium-doped yttrium aluminum perovskite (Nd: YAP), Emblica officinalis (E. officinalis) on the removal of smear layer (SL) and push out bond strength (PBS) of resin-based root canal sealer to the radicular dentin.

METHODS

The coronal portion of sixty single-rooted human mandibular premolar teeth was precisely sectioned at the cementoenamel junction. The canals were prepared to utilize ProTaper universal rotary files till F3. All the study specimens were divided into four groups based on the disinfection regime (n = 15) Group 1: 5.25% NaOCl, Group 2: MBE, Group 3: Nd: YAP laser and Group 4: E. officinalis extract. All the canals were then finally irrigated using 17% EDTA solution as a final disinfecting agent. SL removal assessment was performed on five samples from each group using a scanning electron microscope (SEM). Ten samples from each group were then filled with root canal filling material and the roots were sectioned. Push-out test and failure mode analysis were performed using the universal testing machine (UTM) and stereomicroscope respectively. The mean scores of PBS and SL removal were compared using a one-way analysis of variance (ANOVA) and Post Hoc Tukey's HSD test p = 0.05.

RESULTS

Group-2 (MBE + EDTA) coronal section (1.50 ± 0.23) exhibited the most effective eradication of SL from the canal space. The apical third of Group-1 (NaOCl+EDTA) (2.68 ± 0.82) samples demonstrated the least effective removal of SL from the radicular canal. The maximum score of PBS of AH plus sealer to the canal dentin was exhibited by the coronal section of Group-2 (MBE + EDTA) (9.55 ± 0.45 MPa) samples. However, the apical third of Group-1 (NaOCl+ EDTA) specimens (5.16 ± 0.32 MPa) demonstrated the minimum EBS.

CONCLUSION

MBE+ EDTA displayed better smear layer removal and bond integrity of AH plus sealer to the root canal dentin. Nd: YAP+ EDTA laser and E.officinalis displayed comparable outcomes to that of control NaOCl+ EDTA.

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.

Effect of Carbodiimide (EDC) on the Bond Strength Longevity of Epoxy Resin-based Endodontic Sealer to Root Dentin: An In-Vitro Study

PURPOSE

EDC (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride) can increase dentin bonding longevity. This study aimed to evaluate the effect of final irrigation of the root canal with EDC on the bond strength (BS) longevity of an epoxy resin-based root-canal sealer.

MATERIALS AND METHODS

Twenty maxillary canines were sectioned and standardized for root length at 17 mm. Roots were instrumented and distributed into 2 groups according to the final irrigation protocol: EDTA 17%+NaOCl 2.5% (C) and EDTA 17%+NaOCl 2.5%+EDC 0.5M (EDC). The canals were dried and filled with AH Plus (Dentsply Sirona). Three slices were obtained per third, and the first slice from each third was used for the immediate push-out test (i) followed by analysis of the failure pattern (n = 10); the second slice from each third was used for the push-out test after 6-month aging (A) followed by analysis of the failure pattern (n = 10); the third slice from each third was used to examine the adhesive interface under confocal laser scanning microscopy (CLSM) (n = 10). Data were analyzed with ANOVA, Fisher's exact and Kruskal-Wallis tests.

RESULTS

Higher BSs were found for EDC-A (5.6 ± 1.9) than for EDC-I (3.3 ± 0.7), C-i (2.5 ± 1.0) and C-i (2.6 ± 1.0) (p = 0.0001), while C-A values were in some cases similar to C-i and in others similar to EDC-i. No statistically significant difference was observed between the thirds (p > 0.05), except for EDC-i, which showed lower BS for the cervical (2.79 ± 0.46) compared to the apical third (3.8 ± 0.5), while the middle third in some cases had values similar to those of the apical and in others to the cervical third (3.2 ± 0.7) (p = 0.032). More mixed adhesive failures were found in the cervical third, and more adhesive failures to the sealer occurred in the middle and apical thirds (p = 0.014). A significant difference was observed between treatments in terms of adaptation of the adhesive interface, with a higher percentage of good adaptation using EDC (66.7%) than using C (40%), and a lower percentage of poor adaptation with EDC (10%) compared to C (20%) (p < 0.05).

CONCLUSION

Root canal irrigation with EDC increased the longevity of the adhesive interface of an epoxy resin-based root-canal sealer.

Influence of 2% chlorhexidine on the dislodgement resistance of AH plus, bioroot RCS, and GuttaFlow 2 sealer to dentin and sealer-dentin interface

Aim

To find out the effects of 2% chlorhexidine (CHX) gel intracanal medicament on the dislodgement resistance of AH Plus, BioRoot RCS, and GuttaFlow 2 Sealer to dentin and on sealer-dentin interface.

Materials and Methods

Sixty single-rooted maxillary canine were taken and divided into two groups based on the treatment: Group 1 - control group (no medicament) (n = 30) and Group 2 - (GLUCO-CHeX 2% Gel) (n = 30). Further, the groups were divided according to the sealer used, namely (A) AH Plus sealer, (B) BioRoot RCS Sealer, and (c) Gutta Flow 2 sealer. Teeth were prepared using rotary instrumentation of file size 35 with a taper of 0.06 and obturation was done. 1 mm thick sections were obtained from the roots. All the sections were checked for push out bond strength using Universal testing machine and mode of failure using stereomicroscope. Some samples were evaluated for sealer-dentin interface using field emission scanning electron microscope.

Results

AH Plus showed higher bond strength compared to BioRoot RCS and GuttaFlow 2. There was no significant difference in the push out bond strength with or without the prior use of 2% CHX medicament (P > 0.05) and also CHX did not affect the mode of failure. However, sealer-dentin interface gap was increased with application of medicament.

Conclusion

Dislodgement resistance of AH Plus sealer is significantly higher than BioRoot RCS and GuttaFlow 2 sealer. The application of 2% CHX intracanal medicament before root canal obturation did not significantly affect the dislodgement resistance of the three tested sealers. 2% CHX medicament did not affect the failure mode of the sealers. Sealer-dentin interface is affected by the use of 2% CHX gel medicament.