Influence of resin cements and root canal disinfection techniques on the adhesive bond strength of fibre reinforced composite post to radicular dentin

Adjunctive use of Er, Cr: YSGG laser, Potassium titanyl Phosphate laser, and photosensitizer on extrusion bond strength of radicular dentin to bioceramic sealers

AIM

To assess the impact of adjunctive final root canal disinfection regime curcumin photosensitizer (CP) activated by Photodynamic therapy (PDT), Er, Cr: YSGG laser (ECL), and Potassium titanyl Phosphate (KTP) laser on the bond integrity of two endodontic Bioceramic (BC) sealers.

MATERIALS AND METHOD

Decoration of eighty human single-rooted teeth was performed up to a cementoenamel junction. After instrumentation, all samples were irrigated with 2.25% NaOCl solution followed by 17% EDTA. The specimens were divided arbitrarily into 8 groups (n = 10) based on the adjunctive final irrigation method used. Group 1 and 5 (Control): No adjunctive regime, cleaned using 2.25% NaOCl + 17% EDTA, group 2 and group 6: CP activated by PDT, Group 3 and Group 7 using ECL, Group 4 and Group 8: KTP laser. Following disinfection samples in groups 1, 2, 3, and 4 were obturated using Sankin apatite root canal sealer (SARS). Specimens in groups 5, 6, 7, and 8 were obturated using Pro-root endo sealer (PRES). Sectioning of samples was performed. The sectioned specimens were subjected to a compressive loading exerted via a steel plunger moving at a 0.5 mm/min crosshead speed till debonding. Means and standard deviations (SD) of EBS of BC sealer with the root canal dentin were assessed using one-way analysis of variance (ANOVA) and Post Hoc Tukey multiple comparison tests. The level of significance was measured at p = 0.05.

RESULTS

The coronal section of samples in group 5 (Na-E-PRES) exhibited the highest bond value. The lowest PBS was displayed by the middle third of specimens in group 6. Group 1 (Na-E-SARS), group 3 (Na-E-ECL-SARS), group 5 (Na-E-PRES), and group 7 (Na-E-ECL-PRES) exhibited comparable bond values (p>0.05). Whereas, group 2 (Na-E-PDT-SARS) and group 4 (Na-E-PTPL-SARS), group 6 (Na-E-PDT-PRES), and group 8 (Na-E-PTPL-PRES) were found to be comparable (p>0.05).

CONCLUSION

Adjunctive use of Er, Cr: YSGG laser displayed better extrusion bond strength with BC root canal sealer compared to CP activated by PDT and KTP laser. Bond strength is influenced by the type of irrigation.

The Restored Premolars Biomechanical Behavior: FEM and Experimental Moiré Analyses

This study applied the finite element method (FEM) and the moiré strip projection method to evaluate the biomechanical behavior of healthy and endodontic-treated premolar teeth. The finite element method and the moiré strip projection method were applied to evaluate the influence of restored materials in association with cervical lesions and were considered as strain estimates for a tooth sample with 21 units, under loads of 25, 50, 75, and 100 N, frontal and oblique applied. The focused cases were: tooth H healthy; tooth A-MOD amalgam; tooth AL-MOD amalgam + lesion; tooth ALR-MOD amalgam + injury restored; tooth R-MOD resin; tooth RL-MOD resin + lesion; tooth RLR-MOD resin + injury restored. The results obtained by FEM simulation can be considered perfectly validated by the results presented by the experimental moiré projection analysis, demonstrating that the FEM numerical analysis can be used to evaluate the biomechanical behavior of healthy and endodontically treated teeth. Developing an alternative protocol to generate FEM three-dimensional models will lead to a ready and inexpensive tool since there is no need for costly equipment for tooth extraction prognosis.

Extrusion bond strength of glass fiber post to radicular dentin after final irrigation using MTAD, EDTA, Pineapple peel extract, and riboflavin

INTRODUCTION

The present study aims to determine the effect of different post-space final irrigants ethylenediaminetetraacetic acid (EDTA), a mixture of Doxycycline citric acid and detergent (MTAD), Riboflavin (RF) and Pineapple peel extract (PPE) on the bond integrity of GFPs bonded to radicular dentin.

MATERIALS AND METHODS

Crowns of forty human mandibular premolars teeth were sectioned up to cementoenamel junction CEJ. Root canal treatment was performed. Gates Glidden drills were used to retrieve gutta-percha from the canal. All the specimens were randomly divided into four groups based on the final irrigant used. Group 1 (NaOCl with EDTA), group 2 NaOCl+ MTAD, group 3 NaOCl+RF and group 4 NaOCl+PPE. Cementation of glass fiber posts (GFPs) was performed using self-etch dual-cure resin cement. Sectioning was performed using a slow-speed saw from the coronal, middle, and apical third under constant water irrigation. A universal testing machine was used to assess push-out bond strength (PBS) and failure mode was evaluated using a Stereomicroscope at 40x magnification. One-way analysis of variance (ANOVA) and Tukey multiple comparison tests were used for statistical analysis (p=0.05).

RESULTS

Group 4 (2.5% NaOCl+ PPE) displayed the highest PBS at all three root levels (Cervical: 11.22±0.74 MPa, Middle: 8.99±0.97MPa, and Apical: 6.00±0.88 MPa). However, Group 1 (2.5% NaOCl+17% EDTA) demonstrated the lowest EBS (Cervical: 9.25±0.17 MPa, Middle: 7.01±1.84 MPa, and Apical: 4.41±0.17 MPa). Inter-group comparison displayed that PBS to be comparable between group 1 and group 3 (2.5% NaOCl+ Riboflavin) (Cervical: 9.74±0.41 MPa, Middle: 7.44±1.18 MPa, and Apical: 4.21±0.05 MPa) (p > 0.05). Whereas, group 2 (1.3% NaOCl+ MTAD) (Cervical: 9.32±1.36 MPa, Middle: 7.17±1.75 MPa, and Apical: 4.85±0.19 MPa) and group 4 demonstrated comparable values of PBS (p >0.05).

CONCLUSION

Pineapple peel extract and a mixture of Doxycycline citric acid and a detergent when used as a final irrigant demonstrated better bond integrity of GFPs to radicular dentin at all three levels coronal, middle and apical.

Influence of Different Conditioning Treatments on the Bond Integrity of Root Dentin to rGO Infiltrated Dentin Adhesive. SEM, EDX, FTIR and MicroRaman Study

The present study aimed to synthesize and equate the mechanical properties and dentin interaction of two adhesives; experimental adhesive (EA) and 5 wt.% reduced graphene oxide rGO) containing adhesive. Scanning electron microscopy (SEM)-Energy-dispersive X-ray spectroscopy (EDX), Micro-Raman spectroscopy, push-out bond strength test, and Fourier Transform Infrared (FTIR) spectroscopy were employed to study nano-bond strength, degree of conversion (DC), and adhesive-dentin interaction. The EA was prepared, and rGO particles were added to produce two adhesive groups, EA-rGO-0% (control) and rGO-5%. The canals of sixty roots were shaped and prepared, and fiber posts were cemented. The specimens were further alienated into groups based on the root canal disinfection technique, including 2.5% sodium hypochlorite (NaOCl), Photodynamic therapy (PDT), and ER-CR-YSGG laser (ECYL). The rGO nanoparticles were flake-shaped, and EDX confirmed the presence of carbon (C). Micro-Raman spectroscopy revealed distinct peaks for graphene. Push-out bond strength test demonstrated highest values for the EA-rGO-0% group after NaOCl and PDT conditioning whereas, rGO-5% showed higher values after ECYL conditioning. EA-rGO-0% presented greater DC than rGO-5% adhesive. The rGO-5% adhesive demonstrated comparable push-out bond strength and rheological properties to the controls. The rGO-5% demonstrated acceptable DC (although lower than control group), appropriate dentin interaction, and resin tag establishment.

Comparison of adhesive bond strength among fiber reinforced post and core with different cementation techniques: In vitro study

AIM

To investigate push-out bond strength (PBS) of fiber post to radicular dentin after using different cementation techniques.

MATERIAL AND METHODS

Sixty single-rooted premolars were disinfected and cleaned by mechanical instrumentation. S1, S2, and SX were used for canal shaping and finishing of the canal was carried out using F1 and F2. This was followed by constant irrigation and smear layer removal using 17%EDTA. The canal was dried filled with gutta-percha and canal space was prepared using a peso reamer. Based on cementation techniques, samples were randomly allocated into six groups. Group 1: One-step Monoblock MC; Group 2: One-step, Monoblock MC-NA (no adhesive) GFP; Group 3: One-step, RX-MC-Monoblock; Group 4: Two-step, RX-MC; Group 5: Two-step, RX-FZ; and Group 6: Two-step RX-FZ-custom post. All specimens were mounted in polyvinyl pipes using acrylic resin up to cement enamel junction. All specimens were mounted in a universal testing machine subjected to push-out forces at a speed of 0.5 mm/min. Five samples from each group were sputter-coated with 6 nm gold thickness for 300 s at 250 mA. The coated specimens were assessed under the scanning electron microscope (SEM). Analysis of variance (ANOVA) and Tukey Kramer multiple comparisons tests were performed to compare means among groups maintaining the level of significance at (p < 0.001).

RESULTS

The highest PBS was displayed in RX-MC-Monoblock (199.020 ± 21.432 MPa). Whereas, lowest PBS was found in Monoblock MC-NA (no adhesive)-GFP (76.440 ± 9.468 MPa). Among one-step groups, RX-MC Monoblock exhibited the highest PBS (199.020 ± 21.432 MPa) comparable to one-step Monoblock MC (134.28 ± 19.37 MPa) (p > 0.05). Similarly, among two-steps groups, two-step RX-MC demonstrated significantly higher PBS values than two-step RX-FZ (143.340 ± 23.68 MPa) and RX-FZ-custom post (86.90 ± 7.41 MPa) (p < 0.05).

CONCLUSION

One-step RX-MC-Monoblock technique using self-adhesive cement and core foundation composite resin material multicore flow when cured simultaneously exhibited the highest bond integrity of post retention compared to other cementation technique.