Effects of an endodontic auxiliary chemical substance on the bond strength of two methacrylate-based endodontic sealers to dentin

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.

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.

Influence of Root Canal Filling Techniques on Sealer Penetration and Bond Strength to Dentin

The influence of root canal filling techniques on the penetration of AH Plus into dentinal tubules was evaluated using confocal laser scanning microscopy (CLSM) and the impact on the bond strength of the filling material on the root dentin was evaluated using the push-out test. Roots of the maxillary central incisors (n=40) were prepared with ProTaper Universal and assigned to four groups: lateral condensation, vertical compaction, modified Tagger hybrid and single cone. After root canal filling with gutta-percha and AH Plus, along with the addition of 0.01% fluorescein, the roots were cut into 2-mm slices. CLSM was performed on the first slice of each root third, followed by the push-out test. The second slice was analyzed under SEM. ANOVA demonstrated a statistically significant difference between the root canal filling techniques and the root thirds (p<0.05). For percent penetration, Tukey's test showed that the vertical compaction (91.77±13.51), lateral condensation (89.18±10.91) and modified Tagger hybrid (87.53±15.42) presented the highest values, which significantly differed (p<0.05) from those of the single cone (78.19±22.46). For bond strength (MPa), lateral condensation (3.42±0.54) and vertical compaction (3.47±0.53) had the highest values (p<0.05), while the modified Tagger hybrid (2.19±0.41) and single cone (0.54±0.21) had the lowest. In conclusion, the lateral condensation, vertical compaction and Modified Tagger's hybrid techniques resulted in greater penetration and bond strength to the intra-radicular dentin.