Nano-β-tricalcium phosphate incorporated root dentin adhesive in the bonding interface of yttria-stabilized tetragonal zirconia polycrystalline post

The aim was to synthesize an experimental adhesive (EA) and then reinforce it with β-tricalcium phosphate (β-TCP, 5 wt%) nanoparticles to yield β-TCP-5% adhesive. The EA and β-TCP nanoparticles were prepared and then integrated together. To characterize the filler nanoparticles, scanning electron microscopy (SEM), Energy Dispersive X-Ray (EDX) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and micro-Raman spectroscopy techniques were utilized. Adhesive was assessed for push-out bond strength with yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramic posts. The Y-TZP posts were cemented in to root dentin of 20 teeth ( n = 20). The adhesives were further evaluated for inter-facial failure types and rheological properties. On SEM micrographs, the β-TCP nanoparticles were seen as non-uniform agglomerates. The EDX mapping demonstrated calcium and phosphate ions presence for the β-TCP-5% group. The FTIR and micro-Raman spectra(s) indicated characteristic bands for β-TCP. The β-TCP-5% adhesive demonstrated higher coronal and apical push-out bond strength values (9.80 ± 1.51 MPa and 8.53 ± 1.46 MPa, respectively) than the EA group. The majority of the failures (> 80%) for both groups were of adhesive-dentin type. The β-TCP-5% adhesive also revealed similar rheological properties to the EA, although the latter had less viscosity than the former. The reinforcing of EA with β-TCP filler nanoparticles ensued an appreciation of the adhesive’s push-out bond strength. However, β-TCP-5% adhesive demonstrated reduced viscosity compared to the EA. Further studies exploring the influence of diverse filler concentrations on different properties of the adhesive are recommended.