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Wollastonite with/without maghemite [(Fe2O3), 0, 3 and 10 wt%] was prepared by facile wet precipitation method. Effect of Fe2O3 presence in the obtained nano‐ceramics on physical structure, morphology, size and the mechanical features was evaluated using X‐ray diffraction, transmission electron microscope, and universal testing machine. Moreover, the in vitro biomineralization was examined using simulated body fluid (SBF) by means of scanning electron microscope/energy dispersive X‐ray, Fourier transform infrared, and inductively coupled plasma. An in vivo study was conducted on 24 adult male mongrel dogs to test the biosafety of fabricated samples in the reconstruction of experimentally induced mandibular bone defects. Bone density was measured through cone beam computed tomography analysis conducted at 1 and 3 months following surgery. Wollastonite was the main phase in all the prepared samples however little maghemite was developed in Fe‐containing samples. No remarkable changes were recognized for physical structure of obtained microcrystalline structures, however, a decrease in particle size was noted in the existence of Fe2O3 (10‐15 nm) when compared to the pure wollastonite (30–50 nm). Mechanical features were dependent on the included Fe2O3 concentration within the wollastonite ceramic matrix. The degree of biomineralization of the samples immersed in SBF was elevated with the increase in Fe2O3 percentage. Clinically, the reconstruction of bone defects was uneventful without any adverse toxic effect. Bone density was significantly increased at 1 and 3 months (p < .001) in grafted defects compared to control ones. Increasing the doping concentrations of iron oxide was associated with significant increase (p < .001) of bone density in all induced defects. Due to the impressive healing effect of current fabricated nano‐ceramics, they are recommended to be utilized as low cost bone graft alternatives.

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The present study aimed to evaluate osteogenic potential and biocompatibility of combining biphasic calcium phosphate with zirconia nanoparticles (4Zr TCP/HA) compared to biphasic calcium phosphate (TCP/HA) for reconstruction of induced mandibular defects in dog model. TCP/HA and 4Zr TCP/HA scaffolds were prepared. Morphological, physicochemical, antibacterial, cytocompatibility characterization were tested. In vivo application was performed in 12 dogs where three critical-sized mandibular defects were created in each dog. Bone defects were randomly allocated into: control, TCP/HA, and 4Zr TCP/HA groups. Bone density and bone area percentage were evaluated at 12 weeks using cone-beam computed tomographic, histopathologic, histomorphometric examination. Bone area density was statistically increased (p < 0.001) in TCP/HA and 4Zr TCP/HA groups compared to control group both in sagittal and coronal views. Comparing TCP/HA and 4Zr TCP/HA groups, the increase in bone area density was statistically significant in coronal view (p = 0.002) and sagittal view (p = 0.05). Histopathologic sections of TCP/HA group demonstrated incomplete filling of the defect with osteoid tissue. Doping with zirconia (4Zr TCP/HA group), resulted in statistically significant increase (p < 0.001) in bone formation (as indicated by bone area percentage) and maturation (as confirmed by Masson trichrome staining) compared to TCP/HA group. The newly formed bone was mature and organized with more trabecular thickness and less trabecular space in between. Physicochemical, morphological and bactericidal properties of combining zirconia and TCP/HA were improved. Combining zirconia and TCP/HA resulted in synergistic action with effective osteoinduction, osteoconduction and osteointegration suggesting its suitability to restore damaged bone in clinical practice. Graphical Abstract