Neodymium-doped yttrium vanadate laser and Phthalocyanine photosensitizer doped chitosan nanoparticle activated via Photodynamic therapy on smear layer and push-out bond strength of fiber post: An in vitro SEM, EDX assessment

Aims

To quantify the effectiveness of different root canal sterilants, i.e., Sodium Hypochlorite (NaOCl), Neodymium-doped Yttrium Vanadate (Nd: YVO₄) laser, Phthalocyanine photosensitizer doped Chitosan nanoparticles activated via Photodynamic therapy (Pc-CNPs-PDT), on smear layer (SL) elimination and push out bond strength (PBS) of glass fiber posts (GFPs) bonded to root dentin.

Materials and methods

Forty-eight human premolars with an approximate root length measuring 15 ± 1 mm were included. Endodontic treatment was performed using a nickel‑titanium rotary instrument followed by obturation. The post space was prepared, and specimens were allocated to four groups based on the disinfection protocol employed. Group 1 (Saline + EDTA), Group 2 (2.25 % NaOCl + EDTA), Group 3 (Nd: YVO4 laser + EDTA), Group 4 (Pc-CNPs-PDT + EDTA). A scanning electron microscope was used to assess the surface topography of CHNPs, energy-dispersive spectroscopy (EDS), and SL removal efficacy. Each post was luted using a dual-cure resin cement. The bonded specimens were sectioned into slices (coronal, middle, and apical). A universal testing machine and a stereomicroscope were used to test the PBS and failure modes, respectively. The dataset underwent analysis through one-way analysis of variance ANOVA and Tukey's test to determine notable differences among groups (p = 0.05).

Results

Coronal section of Group 4 (Pc (CHNPs)-PDT + EDTA) samples exhibited maximum SL removal. Whereas, minimum SL elimination was displayed by Saline pretreated canals at the apical section. Samples irrigated with 2.5 % NaOCl + EDTA and Pc (CHNPs)-PDT + EDTA presented comparable scores of bond integrity at all three root sections.

Conclusion

Phthalocyanine photosensitizer doped Chitosan nanoparticles, activated via Photodynamic therapy, can be considered as a suitable alternative to the gold standard technique, NaOCl and EDTA, in removing smear layer and improving glass fiber post adhesion to canal dentin.