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.

Abstract

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.