Effect of different root canal irrigants on push-out bond strength of two novel root-end filling materials

Efficacy of canal disinfectants Temoporfin, carbon nanoparticles, and Er: YAG laser on martens hardness, smear layer removal, and bond strength of glass fiber posts to canal dentin

AIM

To investigate the effectiveness of unconventional post space disinfection techniques, specifically Er:YAG laser, Temoporfin, and Carbon Nanoparticles (CNPs), in improving Martens hardness (MH), eliminating the smear layer (SL), and enhancing the push-out bond strength (PBS) of glass fiber posts in canal dentin.

METHODS

An in vitro study was conducted utilizing 80 single-rooted extracted human teeth, which were decoronated and subjected to standardized root canal preparation. The teeth were equally distributed into four experimental groups: Group 1 (NaOCl + EDTA), Group 2 (Er: YAG laser + EDTA), Group 3 (Temoporfin + EDTA), and Group 4 (CNPs + EDTA). Each group underwent disinfection protocols followed by assessment of Martens hardness (MH) using nanoindentation testing, SL evaluation via scanning electron microscopy, and bond strength testing using a universal testing machine (UTM). Statistical analysis was performed using one-way ANOVA followed by Tukey's post hoc test to determine the level of significance among the groups. A significant level of p<0.05 was established.

RESULTS

Group 4 (CNPs+17 % EDTA) showed a high MH value of (0.25 ± 0.02 GPa), significantly outperforming Groups 1 (0.13 ± 0.02 GPa) and 3 (0.10 ± 0.03 GPa). Group 2 (Er: YAG laser + 17 % EDTA) demonstrated superior smear layer removal across all sections, particularly in the apical third (1.94 ± 0.38). Push-out bond strength was highest in Group 2 (9.98 ± 0.14 MPa at the cervical level) and Group 4 (10.08 ± 0.21 MPa), while Group 1 showed a decrease in apical bond strength of (5.11 ± 0.19 MPa) CONCLUSION: CNPs and Er:YAG laser treatments, in comparison to Temoporfin and NaOCl, significantly increase dentin hardness and bond strength while reducing SL. This finding suggests that the incorporation of these innovative disinfection methods into endodontic procedures may enhance the durability and success of glass fiber post restorations.

Evaluation of the Effects of Retro-Cavity Preconditioning with or Without Ethylenediaminetetraacetic Acid on Root Surface pH and Dislodgement Resistance of NeoMTA2 and Mineral Trioxide Aggregate Flow Retro-Fills: An Ex Vivo Investigation

Background: The aim of this study was to investigate the effects of retro-cavity preconditioning with or without 17% ethylenediaminetetraacetic acid (EDTA) solution on root surface pH as well as dislodgement resistance of NeoMTA2 and MTA Flow retro-fills. Methods: Forty-eight single-rooted human incisors were selected. After completion of endodontic treatment, root-end resections were performed, and retro-cavities were prepared. The samples were randomly divided into two groups of A and B (n = 24 each). In group A, retro-cavities were preconditioned with 2.5% NaOCl, followed by 17% EDTA solution, whereas in group B, preconditioning was performed using 2.5% NaOCl before final irrigation with normal saline. Samples in each group were randomly subdivided into two subgroups of 1 and 2. Retro-fillings in the A1 and B1 subgroups were performed with MTA Flow, and in the A2 and B2 subgroups, they were performed with NeoMTA2. Root surface pH was measured in each sample at three different stages: before preparation of retro-cavities (pH0), after retro-cavity preconditioning (pH1), and three days after retro-filling (pH2). Subsequently, the push-out bond strength (PBS) of the retro-filling materials was measured by a universal testing machine, and their failure modes were visualized under 64× magnification. Results: Preconditioning with EDTA caused a significant increase in PBS for both NeoMTA2 and MTA Flow (p < 0.001). There was no significant difference between the average bond strength of MTA Flow and Neo MTA2 (p = 0.271). There was a significant increase in the average pH2 compared to pH1 and pH0 across all groups (p < 0.001). Specifically, the use of EDTA led to a notable increase in the average pH2 in the MTA Flow group compared to the Neo MTA2 group (p = 0.027). Groups preconditioned with EDTA more frequently indicated a cohesive failure mode. Conclusions: The use of EDTA significantly increased the push-out bond strength of retro-fill materials to dentin. However, it did not prevent the ultimate alkalinity of retro-filled cavities.

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.

Assessment of Smear Layer Removal and Push-Out Bond Strength Efficacy of Traditional and Herbal Root Canal Irrigants Across Different Root Levels: An In Vitro Study

INTRODUCTION

Endodontic therapy requires meticulous root canal debridement, pathogen elimination, and effective obturation to prevent microbial intrusion. The presence of the smear layer hinders sealer penetration, compromising sealing effectiveness. Sodium hypochlorite and chlorhexidine are esteemed endodontic irrigants. Herbal extracts like neem and tulsi, with antimicrobial and anti-inflammatory properties, show promise for root canal irrigation. The study aimed to evaluate the efficacy of various irrigants in removing the smear layer and enhancing push-out bond strength at different root canal levels.

MATERIALS AND METHODS

One hundred mandibular premolars with single canals were collected, and 50 samples each were used for the smear layer and push-out bond strength analysis. Neem and tulsi extracts were prepared for irrigation. Teeth were decoronated, and up to 30 (6%) canals were prepared and were randomly divided into five groups based on irrigants used. A smear layer examination was conducted after longitudinally sectioning the tooth and sections were observed in a scanning electron microscope (SEM). Obturation was done in the remaining samples, and the push-out bond strength was assessed using a universal test machine.

RESULTS

Sodium hypochlorite showed the highest smear layer removal efficacy followed by chlorhexidine, neem, tulsi leaves with rose water extract, and normal saline. Chlorhexidine exhibited the highest push-out bond strength, with the coronal third presenting the strongest values, followed by neem, tulsi with rose water, normal saline, and sodium hypochlorite.

CONCLUSION

The study underscores the potential of herbal irrigants in endodontic therapy, indicating promising results while emphasizing the necessity for further clinical trials to validate their efficacy and other properties.

Physicochemical properties of AH plus bioceramic sealer, Bio-C Sealer, and ADseal root canal sealer

BACKGROUND

The aim of this study was to evaluate the physicochemical properties of two newly introduced premixed calcium silicate-based root canal sealers (AH Plus Bioceramic Sealer and Bio-C Sealer) compared to a resin-based root canal sealer (ADseal root canal sealer).

METHODS

Solubility, pH analysis, calcium ion release, and film thickness of each sealer were evaluated following ISO guidelines. The data were examined using the two-way ANOVA test. Furthermore, X-ray diffraction (XRD) examination was performed to investigate the crystalline phase of each type of sealer. X-ray fluorescence (XRF) analysis was done for the chemical elemental analysis of each sealer.

RESULTS

The least film thickness, highest alkalinity, and highest calcium ion release were all displayed by AH Plus Bioceramic Sealer. High solubility, high alkalinity, intermediate calcium ion release, and intermediate film thickness were all displayed by Bio-C Sealer. While ADseal root canal sealer displayed the greatest film thickness, least solubility, alkalinity, and calcium ion release.

CONCLUSIONS

Both AH Plus Bioceramic Sealer and Bio-C Sealer represented adequate properties to be considered a good sealer that could be used as a potential alternative to resin-based root canal sealers.

The adhesive strength of fiber post-to-canal dentin with Aniline green, Fotoenticine activated by PDT, green tea, and ozone as a final irrigant

AIM

The effect of novel final disinfection protocols Malachite green (MG), Fotoenticine® (FTC), Green tea extract (GTE), and Ozonated water (OW) on the bond strength of prefabricated glass fiber posts (PGFP) adhered to canal dentin.

MATERIAL AND METHOD

The canals of fifty premolars with closed apices were cleansed and obturated. The specimens were randomly assigned to one of five groups based on the final irrigant used, with the control group receiving NaOCl+EDTA and the experimental groups receiving MG, FTC, OW, and GTE. The GFP was cemented with a self-etching, dual-cure paste; the bond strength was estimated with a universal testing machine; and failure analysis was conducted with a stereomicroscope.

RESULTS

The highest PBS was observed in the coronal third of Group 4 (using ozonated water as the final irrigant), whereas the lowest bond integrity was observed in the apical section of Group 2 (1.02-0.54 MPa) using Malachite green as the final irrigant. Group 1, Group 4, and Group 5 exhibited no significant difference in the bond integrity of GFP to dentin when compared to Group 2 (p>0.05). In addition, comparable bond score values were obtained for Groups 2 and 3 (p>0.05).

CONCLUSION

The results of this study suggest that OW and GTE may be effective final disinfectants for root canals, as they increase the bond strength of resin-luting cement.

Impact of endodontic irrigants on surface roughness of various nickel-titanium rotary endodontic instruments

BACKGROUND

The aim of the current study is to assess the surface roughness of several recent nickel-titanium (Ni-Ti) rotary endodontic instruments, namely: Protaper next (PTN); Hyflex CM (CM); Hyflex EDM (EDM); WaveOne gold (WOG); and trunatomy (TN), before and after application of 5.25% sodium hypochlorite (NaOCl) irrigant solution.

METHODS

In this in vitro study, five recently introduced rotary endodontic instruments of different metallurgical properties and designs were subjected to Atomic Force Microscopy (AFM) analysis, and then each file was rotated in 5.25% NaOCl for 15 min., with speed and torque according to manufacturer's instructions. The instruments were then subjected to AFM analysis again. The surface roughness average (Sa) parameter was calculated. Data were analyzed by Paired T test, One-way ANOVA and Tukey tests.

RESULTS

There was a statistically significant decrease in the surface roughness of all rotary endodontic instruments after immersion in irrigants (P ≤ 0.05).

CONCLUSION

The new TN and PTN instruments showed the least surface roughness. All tested Ni-Ti rotary endodontic instruments after irrigants exposure showed a varying increase in surface roughness.