Push out bond strength of glass fiber post to radicular dentin irrigated with Nisin and MTAD compared to methylene blue photodynamic therapy

Aim: Present lab-based study intended to appraise the effect of nisin, Mixture of Tetracycline, Acid and Detergent (MTAD), and photodynamic therapy (PDT) when used as a canal disinfectant on push-out bond strength (PBS) of fiber post to radicular dentin Materials and methods: Forty uni-radicular premolar teeth were extracted and disinfected in 0.5 % thymol solution. All specimens were decoronated to achieve standardize root length of 14 mm. Cleaning and shaping of the canal were done using protaper NiTi system. The canal space was dried and obturated. Post space was prepared using peso reamers up to 10 mm length and samples were randomly divided into 4 groups (n = 10). Group 1 irrigated with 10 % Nisin with MTAD, group 2: 1.3 % NaOCl and MTAD, Group 3 irrigated with 2.5 % NaOCl and 17 % EDTA and post space of samples in group 4 with PDT with MTAD. Fiber-reinforced composite post (FRCP) was fitted in canal space using self-etch resin cement. Each sample was cut into 1 mm from coronal, middle, and apical and subjected to PBS via a universal testing machine. For comparison of means, Analysis of variance (ANOVA) and Tukey multiple comparison test was used maintaining the level of significance at p < 0.05. Result: Samples in group 3 post space irrigated with 2.5 % NaOCl and 17 % EDTA demonstrated the highest PBS at all root levels (cervical: 8.83 +/- 0.14 MPa, middle: 7.63 +/- 0.82 MPa and apical: 5.82 +/- 0.32 MPa) in comparison to other tested groups. Whereas, group 1 in which Nisin 10 % with MTAD was used as a canal disinfectant displayed the lowest PBS at all levels (cervical: 6.91 +/- 0.54 MPa, middle: 6.15 +/- 0.31 MPa, and apical: 3.62 +/- 0.68 MPa). Conclusion: Post space irrigated with 1.3 % NaOCl and MTAD shows PBS similar to control group 2.5 % NaOCl and 17 % EDTA. Both types of irrigation methods have potential and can be recommended in clinical scenarios. Whereas, 10 % Nisin and PDT with MTAD as chelator needs further inquiry.

Automated summary

The study evaluated the effect of different canal disinfectants on the push-out bond strength of fiber posts to radicular dentin. Results showed that irrigation with 2.5% NaOCl and 17% EDTA resulted in the highest PBS, while using 10% Nisin with MTAD led to the lowest PBS. Irrigation with 1.3% NaOCl and MTAD showed similar PBS to the control group. Both methods are recommended for clinical use, while further investigation is needed for 10% Nisin and PDT with MTAD.