Biphasic calcium phosphate doped with zirconia nanoparticles for reconstruction of induced mandibular defects in dogs: cone-beam computed tomographic and histopathologic evaluation.

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.

Effect of Laser Bio-Stimulation on Mandibular Distraction Osteogenesis: An Experimental Study.

PURPOSE: The aim of this study was to evaluate the osseous response to laser bio-stimulation clinically and histologically during distraction osteogenesis (DO) induced in the mandibles of mongrel dogs. MATERIALS AND METHODS: Thirty dogs were divided into 3 groups of 10 (5 with and 5 without laser treatment) according to sacrifice periods (2, 4, and 8 weeks after distraction). DO was performed between the mandibular second and third premolars using an internal linear distractor. After a 7-day latency period, the distractor was activated at the rate of 1 mm per day for 10 days followed by a consolidation period during which the right mandibular side was irradiated with a diode laser (wavelength [λ], 970 nm; power, 2 W; spot size, 320 µm; total energy [E], 840 J), whereas the control group was not irradiated, after distraction. Histologic specimens were prepared and histomorphometric analysis of specimens was performed. RESULTS: Clinical examinations showed that the low-intensity laser diode had a pronounced effect on the quality and quantity of newly formed bone in the DO regenerate in the laser groups compared with the control groups. Histopathologic sections from laser groups I, II, and III displayed the bio-stimulatory effect of laser on new bone through an increased rate of osteoblast proliferation and differentiation, an accelerated rate of intramembranous ossification, and increased neoangiogenesis compared with the control groups. Moreover, the histomorphometric results showed that mean bone trabecular size, bone trabecular total area, and bony area fraction of the regenerate were larger and statistically significant (P < .05) especially in laser groups I and II (early stages of bone formation) compared with the control groups. CONCLUSION: The low-level diode laser had a positive role as a potential bio-stimulator and local inducer in enhancing bone formation during DO and resulted in early stability of the bone regenerate, a shorter total treatment time, and improved new bone quality and quantity.

Efficacy of photobiomodulation using diode laser 650 nm combined with nano-cellulose and nano-amorphous calcium phosphate in bone healing of rabbit tibial defects assessed by H&E staining and computed tomography.

BACKGROUND: The purpose of the current study was to evaluate the effect of Diode LLLT 650 nm, TEMPO oxidized Nano-fibrillated cellulose mixed with Nano-Amorphous calcium phosphate, and their combination on bone healing in rabbit tibia using H&E staining and computed tomography. METHODS: Eighteen adult male New Zealand rabbits were selected, two circular bone defects were created in each tibia, resulting in four bony defects in each rabbit, representing the four tested groups; group A (negative control), group B (filled with mineralized nano-cellulose), group C (combination), group D (laser). Animals were euthanized after two weeks and one month, defects were assessed by CT for bone density, then histological samples were examined by H&E stain. RESULTS: In both evaluation periods, group D recorded the greatest mean area percent of new bone formation and bone density, followed by group A, while group C recorded the lowest value. Groups A and D showed full closure of the defects, while groups B and C showed partial defect closure with retained bone graft material. H&E and CT showed that Laser group had the best results of defects healing, bone density and new bone formation, followed by the negative control group. CONCLUSIONS: Diode laser 650nm photobiomodulation significantly improved bone defects healing. Mineralized nano-cellulose experimental bone substitute material showed a delayed effect in bone healing and graft material resorption. The combination of LLLT with the graft material had no positive outcome on bone defect healing.

Osteogenic potential of calcium silicate-doped iron oxide nanoparticles versus calcium silicate for reconstruction of critical-sized mandibular defects: An experimental study in dog model.

Objective: To evaluate bioactivity and osteogenic potential of calcium silicate (CS)-doped iron oxide (Fe2O3) nanoparticles versus pure CS in the reconstruction of induced critical-sized mandibular defects. Design: CS-doped Fe2O3 was prepared; morphological and microstructure identification of nanoparticles were made. An in vivo randomised design was developed on 24 adult male dogs where four critical-sized mandibular defects were created in each dog. Bone defects were allocated into control, CS, CS-3% Fe2O3 and CS-10% Fe2O3 group. Dogs were euthanized at 1 and 3 months (12 dog/time) for histopathologic and histomorphometric evaluation. Results: At three months, bone formation and maturation were evident where mean ± SD percent of mature bone was 2.66 ± 1.8, 9.9 ± 2.5, 22.9 ± 4.9, and 38.6 ± 8.1 in control, CS, CS-3% Fe2O3, and CS-10% Fe2O3 groups respectively. A high significant (P < 0.001) increase in area percent of mature bone was recorded in CS, CS-3% Fe2O3, and CS- 10% Fe2O3 groups compared to control group (73%, 88% and 93.3% respectively). Significant increase (P < 0.001) in area of mature bone was recorded in CS-3% Fe2O3 and CS-10% Fe2O3 groups compared to CS group. A significant increase (P < 0.001) in area of mature bone formation was detected in CS-10% Fe2O3 group compared to other groups. Conclusion: CS-doped Fe2O3 has good osteoconductive, biocompatible properties with promoted bone regeneration. Fe2O3 has synergistic effect in combination with CS to promote bone formation. Increasing concentration of Fe2O3 nanoparticles resulted in improved osteogenesis and maturation. Results suggests that the novel CS-Fe2O3 alloplasts could be used for reconstruction of critical-sized bone defects.

Radiological evaluations of low cost wollastonite nano-ceramics graft doped with iron oxide in the treatment of induced defects in canine mandible.

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.