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

Aim: To determine the push out bond strength (PBS) of fibre reinforced composite post (FRCP) bonded to radicular dentin using different cement types total etch resin cement (TERC) and Self-adhesive resin cement (SARC) conditioned with (PDT, 5.25 % NaOCl with EDTA and 1% NaOCl) Materials and methods: Sixty freshly extracted (orthodontic purpose) human single rooted mandibular premolars were collected. Teeth were disinfected and coronal part of all samples were removed. Cleaning shaping and finishing of canal space was performed and filled with gutta percha via lateral condensation. Post space was prepared and disinfected with three irrigating solutions. Samples in group 1 and 2 disinfected 5.25 % NaOCl with EDTA, group 3 and 4 steriled with 1% NaOCl and group 5 and 6 disinfected with Methylene Blue photodynamic therapy (PDT). Based on the resin cement, FRCP was luted with TERC in group 2, 4 and 5; and with SARC in group 1,3 and 6 respectively. All specimens were subjected to aging and push-out bond strength (PBS) on universal testing machine after sectioning of each sample in three segments (coronal, middle and apical). Following push out bond strength (PBS), debonded surface were observed under stereomicroscope at 40x magnification. PBS were equated by means of analysis of variance (ANOVA) and Tukey's post hoc test maintaining level of significance (p < 0.05) Results: Group 1 (SARC) and 2 (TERC) disinfected with 5.25 % NaOCl with 17 % EDTA, TERC (group 2) showed higher extrusion bond strength at all three levels coronal (9.25 ± 0.21 MPa) middle (8.81 ± 0.94 MPa) and apical (8.21 ± 0.93 MPa). Whereas, canal space sterilized with 1% NaOCl [group 3 (SARC) and group 4 (TERC)], posts cemented with TERC exhibited the higher PBS at all three levels of root canal (10.22 ± 0.36 MPa), (9.68 ± 0.51 MPa), (6.33 ± 0.08 MPa). Similarly, among PDT disinfected fiber post [group 5 (TERC) and group 6 (SARC)], TERC exhibited the greater PBS values at coronal, middle and apical levels (6.25 ± 0.39 MPa) (5.17 ± 0.22 MPa) (4.32 ± 0.69 MPa) compared to SARC specimens Conclusion: Irrespective of canal irrigant, fiber post bonded with TERC showed higher PBS at coronal and middle third. Fiber post bonded with SARC when irrigated with 5.25 % NaOCl with EDTA, 1% NaOCl displayed higher PBS at apical third. Canal disinfected using PDT showed lower PBS for FRCP compared to 5.25 % NaOCl with EDTA and 1% NaOCl.