Calvarial Bone Defects Research Articles

Cranioplasty using Titanium Mesh Versus Acrylic Bone Cement: Short-term Outcomes and Complications

Background: Cranioplasty is a reconstructive procedure to restore bone anatomy and repair skull defects. Optimum reconstruction could be a challenge for neurosurgeons, and therefore the strategy to attain the ideal result remains a subject of discussion. Aim: we aimed at comparing two completely different prostheses in reconstructing calvarial bone defects, titanium mesh and polymethyl methacrylate (PMMA) bone cement. We looked for the differences in the cosmetic and functional outcomes as well as the prosthesis-related complications. Patients and Methods: This was a randomized prospective study on the first forty successive adult patients with calvarial skull defects of different etiologies, sites and sizes admitted and operated upon at neurosurgery department, Minia University hospital between January 2017 and December 2018. We divided patients into 2 groups, Group1: 20 patients were operated upon using Titanium mesh and Group 2: 20 patients were operated upon using (PMMA) acrylic bone cement implants. Results: Regarding cosmetic appearance, functional outcome, and improvement of the clinical symptoms (syndrome of trephined), Cranioplasty using titanium mesh and acrylic bone cement proved to have non-significant differences in the reconstruction of calvarial skull defects of different etiologies. However, there is a statistically significant difference between both materials regarding complications especially with large skull defects (≥25 cm2). Conclusion: there is no statistical difference between both materials regarding cosmetic and functional outcomes. However, large bone defects (≥25 cm2)are better treated with titanium mesh due to lower incidence of complications.

Bone regeneration in critical-size calvarial defect using functional biocompatible osteoinductive herbal scaffolds and human umbilical cord Wharton’s Jelly-derived mesenchymal stem cells

Critical size calvarial bone defects and their repair is the major challenge in orthopaedic surgery. Bone tissue engineering using varied combinations of scaffolds, stem cells, and growth factors is an emerging choice of treatment for variety of bone defects. Present study aimed to compare and evaluate the potential of poly ε-caprolactone (PCL), PCL- graphene oxide (GO), PCL-GO-Cissus quadrangularis (CQ), and human umbilical cord-derived mesenchymal stem cells (hUCMSCs) seeded PCL (PCL- hUCMSCs), PCL-GO-CQ-hUCMSCs scaffolds to heal critical size calvarial bone defect in the rat models. Healthy adult Wister female rats (N = 30) with average body weight of 350 ± 30 g were divided to 6 groups with five animals in each group. Single critical size calvarial defects of 8 mm were created in the skull of each rat and same were treated with respective scaffolds. The outcome of the treatments was evaluated at 6 weeks and 12 weeks in terms of weight, haematological parameters and biochemical parameters for biocompatibility. New bone regeneration/healing was analysed using digital radiography and micro-computed tomography. Quality of bone formed was analysed by bone mineral density. Histological analysis of the bone tissues was performed using an optical microscope. All the scaffolds were biocompatible and there was no adverse effect of these scaffolds on animals. Higher bone regeneration was observed after 12 weeks of transplantation than 6 weeks. However, PCL-GO-CQ-hUCMSCs scaffolds exhibited highest bone regeneration 12 weeks post-transplantation. The unique combination of PCL-GO-CQ-hUCMSCs scaffold proved to be beneficial in bone regeneration by aiding nearly complete healing of defect site. Further studies with PCL-GO-CQ-hUCMSCs could pave the way for human clinical trials.

Bi-directional regulation functions of lanthanum-substituted layered double hydroxide nanohybrid scaffolds via activating osteogenesis and inhibiting osteoclastogenesis for osteoporotic bone regeneration.

Rationale: Osteoporotic patients suffer symptoms of excessive osteoclastogenesis and impaired osteogenesis, resulting in a great challenge to treat osteoporosis-related bone defects. Based on the positive effect of rare earth elements on bone metabolism and bone regeneration, we try to prove the hypothesis that the La3+ dopants in lanthanum-substituted MgAl layered double hydroxide (La-LDH) nanohybrid scaffolds simultaneously activate osteogenesis and inhibit osteoclastogenesis.Methods: A freeze-drying technology was employed to construct La-LDH nanohybrid scaffolds. The in vitro osteogenic and anti-osteoclastogenic activities of La-LDH nanohybrid scaffolds were evaluated by using ovariectomized rat bone marrow stromal cells (rBMSCs-OVX) and bone marrow-derived macrophages (BMMs) as cell models. The in vivo bone regeneration ability of the scaffolds was investigated by using critical-size calvarial bone defect model of OVX rats.Results: La-LDH nanohybrid scaffolds exhibited three-dimensional macroporous structure, and La-LDH nanoplates arranged perpendicularly on chitosan organic matrix. The La3+ dopants in the scaffolds promote proliferation and osteogenic differentiation of rBMSCs-OVX by activating Wnt/β-catenin pathway, leading to high expression of ALP, Runx-2, COL-1 and OCN genes. Moreover, La-LDH scaffolds significantly suppressed RANKL-induced osteoclastogenesis by inhibiting NF-κB signaling pathway. As compared with the scaffolds without La3+ dopants, La-LDH scaffolds provided more favourable microenvironment to induce new bone in-growth along macroporous channels.Conclusion: La-LDH nanohybrid scaffolds possessed the bi-directional regulation functions on osteogenesis and osteoclastogenesis for osteoporotic bone regeneration. The modification of La3+ dopants in bone scaffolds provides a novel strategy for osteoporosis-related bone defect healing.

Hydrogel mechanics are a key driver of bone formation by mesenchymal stromal cell spheroids

Mesenchymal stromal cells (MSCs) can promote tissue repair in regenerative medicine, and their therapeutic potential is further enhanced via spheroid formation. Stress relaxation of hydrogels has emerged as a potent stimulus to enhance MSC spreading and osteogenic differentiation, but the effect of hydrogel viscoelasticity on MSC spheroids has not been reported. Herein, we describe a materials-based approach to augment the osteogenic potential of entrapped MSC spheroids by leveraging the mechanical properties of alginate hydrogels. Compared to spheroids entrapped in covalently crosslinked elastic alginate, calcium deposition of MSC spheroids was consistently increased in ionically crosslinked, viscoelastic hydrogels. We previously demonstrated that intraspheroidal presentation of Bone Morphogenetic Protein-2 (BMP-2) on hydroxyapatite (HA) nanoparticles resulted in more spatially uniform MSC osteodifferentiation, providing a method to internally influence spheroid phenotype. In these studies, we observed significant increases in calcium deposition by MSC spheroids loaded with BMP-2-HA in viscoelastic gels compared to soluble BMP-2, which was greater than spheroids entrapped in all elastic alginate gels. Upon implantation in critically sized calvarial bone defects, bone formation was greater in all animals treated with viscoelastic hydrogels. Increases in bone formation were evident in viscoelastic gels, regardless of the mode of presentation of BMP-2 (i.e., soluble delivery or HA nanoparticles). These studies demonstrate that the dynamic mechanical properties of viscoelastic alginate are an effective strategy to enhance the therapeutic potential of MSC spheroids for bone formation and repair.

3D bioprinting of graphene oxide-incorporated cell-laden bone mimicking scaffolds for promoting scaffold fidelity, osteogenic differentiation and mineralization

Bioprinting is a promising technique for facilitating the fabrication of engineered bone tissues for patient-specific defect repair and for developing in vitro tissue/organ models for ex vivo tests. However, polymer-based ink materials often result in insufficient mechanical strength, low scaffold fidelity and loss of osteogenesis induction because of the intrinsic swelling/shrinking and bioinert properties of most polymeric hydrogels. Here, we developed a human mesenchymal stem cells (hMSCs)-laden graphene oxide (GO)/alginate/gelatin composite bioink to form 3D bone-mimicking scaffolds using a 3D bioprinting technique. Our results showed that the GO composite bioinks (0.5GO, 1GO, 2GO) with higher GO concentrations (0.5, 1 and 2 mg/ml) improved the bioprintability, scaffold fidelity, compressive modulus and cell viability at day 1. The higher GO concentration increased the cell body size and DNA content, but the 2GO group swelled and had the lowest compressive modulus at day 42. The 1GO group had the highest osteogenic differentiation of hMSC with the upregulation of osteogenic-related gene (ALPL, BGLAP, PHEX) expression. To mimic critical-sized calvarial bone defects in mice and prove scaffold fidelity, 3D cell-laden GO defect scaffolds with complex geometries were successfully bioprinted. 1GO maintained the best scaffold fidelity and had the highest mineral volume after culturing in the bioreactor for 42 days. In conclusion, GO composite bioinks had better bioprintability, scaffold fidelity, cell proliferation, osteogenic differentiation and ECM mineralization than the pure alginate/gelatin system. The optimal GO group was 1GO, which demonstrated the potential for 3D bioprinting of bone tissue models and tissue engineering applications.

Calvarial bone defects in ovariectomised rats treated with mesenchymal stem cells and demineralised freeze-dried bone allografts.

The aim of the study was to investigate the ability of a combination of bone marrow mesenchymal stem cells (BM-MSCs) with and without demineralised freeze-dried bone allografts (DFDBAs) to induce bone regeneration in calvarial defects in ovariectomised rats. Critical size defects were filled with a combination of DFDBAs and BM-MSCs or BM-MSCs alone. Eight weeks after calvarial surgery, the rats were sacrificed. The samples were analysed histologically and immunohistochemically. No difference was observed in vascularisation between groups C1 (animals with cranial defect only, control group) and O1 (animals with cranial defect only, ovariectomy group). Intramembranous ossification was observed at a limited level in groups C2 (animals with cranial defect with MSCs, control group) and O2 (animals with cranial defect with MSCs, ovariectomy group) compared to C1 and O1. In group C3 (animals with DFDBAs with MSCs, control group), the fibrous structures of the matrix became compact as a result of a bone graft having been placed in the cavity, but in group O3 (animals with DFDBAs with MSCs, ovariectomy group), the fibrous tissue was poorly distributed between the bone grafts for the most parts. We conclude that the insertion of BM-MSCs enhances bone healing; however, the DFDBA/BM-MSC combination has little effect on overcoming impaired bone formation in ovariectomised rats.

Comparison of bone regenerative capacity of donor-matched human adipose\u2013derived and bone marrow mesenchymal stem cells

Adipose-derived stem cells (ASC) have been used as an alternative to bone marrow mesenchymal stem cells (BMSC) for bone tissue engineering. However, the efficacy of ASC in bone regeneration in comparison with BMSC remains debatable, since inconsistent results have been reported. Comparing ASC with BMSC obtained from different individuals might contribute to this inconsistency in results. Therefore, this study aimed to compare the bone regenerative capacity of donor-matched human ASC and BMSC seeded onto poly(l-lactide-co-ε-caprolactone) scaffolds using calvarial bone defects in nude rats. First, donor-matched ASC and BMSC were seeded onto the co-polymer scaffolds to evaluate their in vitro osteogenic differentiation. Seeded scaffolds and scaffolds without cells (control) were then implanted in calvarial defects in nude rats. The expression of osteogenesis-related genes was examined after 4 weeks. Cellular activity was investigated after 4 and 12 weeks. Bone formation was evaluated radiographically and histologically after 4, 12, and 24 weeks. In vitro, ASC and BMSC demonstrated mineralization. However, BMSC showed higher alkaline phosphatase activity than ASC. In vivo, human osteogenesis–related genes Runx2 and collagen type I were expressed in defects with scaffold/cells. Defects with scaffold/BMSC had higher cellular activity than defects with scaffold/ASC. Moreover, bone formation in defects with scaffold/BMSC was greater than in defects with scaffold/ASC, especially at the early time-point. These results suggest that although ASC have the potential to regenerate bone, the rate of bone regeneration with ASC may be slower than with BMSC. Accordingly, BMSC are more suitable for bone regenerative applications.

In-situ stable injectable collagen-based hydrogels for cell and growth factor delivery

Here we report development of in-situ stable injectable hydrogels for delivery of cells and growth factors based on two precursors, alginate, and collagen/calcium sulfate (CaSO4). The alg/col hydrogels were shear-thinning, injectable through commercially available needles and stable right after injection. Rheological measurements revealed that pre-crosslinked alg/col hydrogels fully crosslinked at 37 °C and that the storage modulus of alg/col hydrogels increased with increasing the collagen content or the concentration of CaSO4. The viscoelastic characteristics and injectability of the alg/col hydrogels were not significantly impacted by the storage of precursor solutions for 28 days. An osteoinductive bone morphogenic protein-2 (BMP-2) loaded into alg/col hydrogels was released in 14 days. Human mesenchymal stem cells (hMSCs) encapsulated in alg/col hydrogels had over 90% viability over 7 days after injection. The DNA content of hMSC-laden alg/col hydrogels increased by 6-37 folds for 28 days, depending on the initial cell density. In addition, hMSCs encapsulated in alg/col hydrogels and incubated in osteogenic medium were osteogenically differentiated and formed a mineralized matrix. Finally, a BMP-2 loaded alg/col hydrogel was used to heal a critical size calvarial bone defect in rats after 8 weeks of injection. The alg/col hydrogel holds great promise in tissue engineering and bioprinting applications.

Polymeric Gelatin Scaffolds Affect Mesenchymal Stem Cell Differentiation and Its Diverse Applications in Tissue Engineering.

Studies using polymeric scaffolds for various biomedical applications, such as tissue engineering, implants and medical substitutes, and drug delivery systems, have attempted to identify suitable material for tissue regeneration. This study aimed to investigate the biocompatibility and effectiveness of a gelatin scaffold seeded with human adipose stem cells (hASCs), including physical characteristics, multilineage differentiation in vitro, and osteogenic potential, in a rat model of a calvarial bone defect and to optimize its design. This functionalized scaffold comprised gelatin-hASCs layers to improve their efficacy in various biomedical applications. The gelatin scaffold exhibited excellent biocompatibility in vitro after two weeks of implantation. Furthermore, the gelatin scaffold supported and specifically regulated the proliferation and osteogenic and chondrogenic differentiation of hASCs, respectively. After 12 weeks of implantation, upon treatment with the gelatin-hASCs scaffold, the calvarial bone harboring the critical defect regenerated better and displayed greater osteogenic potential without any damage to the surrounding tissues compared to the untreated bone defect. These findings suggest that the present gelatin scaffold is a good potential carrier for stem cells in various tissue engineering applications.

Effect of doxycycline-bioglass treatment on calvarial bone defect in rats: A histological study

Purpose: To evaluate the osteogenic properties of a bioglass-doxycycline complex for bone regeneration applications in calvarial bone defects in rats.Methods: Three critical-size bone defects were created in each of eight experimental rats using a trephine bur. The experimentally created defects were then filled with bioglass-doxycycline (BG-D group), bioglass alone (BG group), or left unfilled (control group). Four randomly selected rats weresacrificed after 4 weeks while the other four rats were sacrificed after 8 weeks. The amount of newly regenerated bone and the osteoblast and osteoclast counts were calculated using histological analysis.Results: Increase in the amount of regenerated bone was significant in the bioglass-doxycycline group at both 4 and 8 weeks (p < 0.05). Differences between the three groups in the mean number of osteoblasts were also significant at both 4 and 8 weeks (p < 0.05). Comparison of the three groupsrevealed significant increase in osteogenesis rate and considerable enhancement of the number of osteoblasts in both bioglass and bioglass-doxycycline groups (p < 0.05).Conclusion: The complex of doxycycline and bioglass increased the rate of osteogenesis and number of osteoblasts in rats but decreased the number of osteoclasts. Therefore, bioglass-doxycycline can be considered as a bone graft in bone regeneration for medical applications.
 Keywords: Bone, Regeneration, Osteoblasts, Osteoclasts, Osteogenesis, Bioglass, Doxycycline

Whitlockite Granules on Bone Regeneration in Defect of Rat Calvaria.

Whitlockite (WH; Ca18Mg2(HPO4)2(PO4)12) is a calcium phosphate based ceramic that contains magnesium ions. As the second most abundant mineral in living bone, WH occupies 25-35 wt % of the inorganic portion of human bone. Compared to hydroxyapatite (HAp, Ca10(PO4)6(OH)2), WH possesses better mechanical properties, faster resorbability, and promotion behavior on the osteogenesis. In this article, we introduced a fabrication method of interconnected porous WH granules through vacuum filtration, followed by sintering treatment based on the thermal stability of WH synthesized using the tri-solvent system. This study presents a histological, radiological, and immunohistochemical evaluation of the bone healing potential of these WH granules in a 5 mm diameter calvarial bone defect in rats. The histological evaluation shows no inflammation or foreign body reaction in the WH group. The WH group displays newly formed bone at the same thickness as the original bone. On the contrary, bone formation is not observed in the nontreated (NT) group. Besides, immunohistochemistry (IHC) confirmed that WH granules promoted bone regeneration with the significantly higher expression of bone morphogenetic proteins-2 (BMP-2), alkaline phosphatase (ALP), osteopontin (OPN), and osteocalcin (OCN) compared to the NT group without the addition of exogenous cells or growth factors. These results suggest that WH has excellent potential for application in bone tissue regeneration.

3D printed bioceramics fabricated using negative thermoresponsive hydrogels and silicone oil sealing to promote bone formation in calvarial defects

The purpose of the present work was to investigate the potential for application and the effectiveness of osteoconductive scaffolds with bicontinuous phases of 3D printed bioceramics (3DP-BCs) based on reverse negative thermoresponsive hydrogels (poly[(N-isopropylacrylamide)-co-(methacrylic acid)]; p(NiPAAm-MAA)). 3DP-BCs have bioceramic objects and microchannel pores when created using robotic deposition additive manufacturing. We evaluated the benefits of silicone oil sealing on the 3DP-BC green body during the sintering process in terms of densification and structural stability. The shrinkage, density, porosity, element composition, phase structure and microstructural analyses and compression strength measurements of sintered 3DP-BC objects are presented and discussed in this study. In addition, the results of cell viability assays and bone healing analyses of the calvarial bone defects in a rabbit model were used to evaluate 3DP-BC performance. The main results indicated that these 3DP-BC scaffolds have optimal continuous pores and adequate compressive strength, which can enable the protection of calvarial defects and provide an environment for cell growth. Therefore, 3DP-BC scaffolds have better new bone regeneration efficiency in rabbit calvarial bone defect models than empty scaffolds and mold-forming bioceramic scaffolds (MF-BCs).

Amplified morphogenetic and bone forming activity of amorphous versus crystalline calcium phosphate/polyphosphate

Amorphous Ca-phosphate (ACP) particles stabilized by inorganic polyphosphate (polyP) were prepared by co-precipitation of calcium and phosphate in the presence of polyP (15% [w/w]). These hybrid nanoparticles showed no signs of crystallinity according to X-ray diffraction analysis, in contrast to the particles obtained at a lower (5% [w/w]) polyP concentration or to hydroxyapatite. The ACP/15% polyP particles proved to be a suitable matrix for cell growth and attachment and showed pronounced osteoblastic and vasculogenic activity in vitro. They strongly stimulated mineralization of the human osteosarcoma cell line SaOS-2, as well as cell migration/microvascularization, as demonstrated in the scratch assay and the in vitro angiogenesis tube forming assay. The possible involvement of an ATP gradient, generated by polyP during tube formation of human umbilical vein endothelial cells, was confirmed by ATP-depletion experiments. In order to assess the morphogenetic activity of the hybrid particles in vivo, experiments in rabbits using the calvarial bone defect model were performed. The particles were encapsulated in poly(d,l-lactide-co-glycolide) microspheres. In contrast, to crystalline Ca-phosphate (containing only 5% [w/w] polyP) or to crystalline β-tricalcium phosphate, amorphous ACP/15% polyP particles caused pronounced osteoinductive activity already after a six-week healing period. The synthesis of new bone tissue was accompanied by an intense vascularization and an increased expression of mineralization/vascularization marker genes. The data show that amorphous polyP-stabilized ACP, which combines osteoinductive activity with the ability to act as a precursor of hydroxyapatite formation both in vitro and in vivo, is a promising material for bone regeneration.

Experimental and clinical evaluation of BMP2-CPC graft versus deproteinized bovine bone graft for guided bone regeneration: A pilot study.

In this study, we proposed BMP2-incorporated calcium phosphate cement (BMP2-CPC), for application in guided bone regeneration (GBR) and compared the experimental bone restoration performance and clinical alveolar bone reconstruction outcome of BMP2-CPC with those of deproteinized bovine bone (DBB). The animal study indicated that, compared to DBB, which induced the slow ingrowth of new bone, BMP2-CPC induced numerous small growth centers for bone regeneration and facilitated a significant amount of bone regeneration in rabbit calvarial bone defects. Fewer residual graft particles remained in the BMP2-CPC-treated defects than in the DBB-treated defects. The clinical study indicated that BMP2-CPC was similar to DBB in remedying alveolar bone insufficiency and maintaining implant stability. In conclusion, the results of this present study indicate that compared to DBB, BMP2-CPC can significantly enhance in vivo bone regeneration and remodeling in rabbit calvarial bone defects and shows preliminary support on its clinical application in GBR surgeries.

A Case of Apert Syndrome: Early Detection of Temporal Lobe Abnormalities and Scalp Cyst in Fetal Brain MRI

Introduction: Apert Syndrome is one of the severe forms of craniosynostosis syndromes. Here we present the first case of 20 weeks fetus with temporal lobe abnormalities with a scalp cyst in fetal MRI. Case Presentation: A 34-year-old woman at 19 weeks of pregnancy presented with normal first trimester scan and with acrocephaly, mild ventriculomegaly (10.5 mm), hypertelorism, and mitten glove syndactyly of hands of the fetus in second trimester ultrasound scan. Also a scalp cyst without calvarial bone defect was found. One week later, fetal brain MRI on 1.5 T scanner confirmed 2D ultrasound findings. Also bilateral temporal lobe overconvolution and low set ears were detected by MRI. These imaging features strongly suggested Apert or a related craniosynostosis syndrome. Amniocentesis result revealed the heterozygous FGFR2 gene mutation consistent with Apert syndrome. Conclusions: Fetal MRI and ultrasound are complementary tools for full evaluation of different aspects of a syndromic condition in fetus that is very important for proper genetic testing and counseling.

Behavior of Osteoclast Cells Response on Dicalcium Phosphate Dihydrate Layer-Coated β-Tricalcium Phosphate Granular

The aim of this study is to investigate the behavior of osteoclast cells response on dicalcium phosphate dihydrate (DCPD) layer-coated β-TCP granules. β-TCP granules with 300-600 μm were exposed to acidic calcium phosphate solution for 30 mins in order to get 10 mol% DCPD layer-coated β-TCP granular. DCPD free-coated β-TCP granular had used as control specimen. Both specimens were implant in 9 mm of rat calvarial bone defect for 4 weeks. After 4 weeks, the block section of rat calvarial containing specimen were removed for Tatrate-Resistance Acid Phosphatase (TRAP) analysis. Results of TRAP staining reveal that the number of osteoclast cells attached on 10 mol% layer-coated β-TCP granular is higher than DCPD free-coated β-TCP granular. Since remodeling of new bone formation involved simultaneous osteoclast and osteoblast cells response, therefore, the results obtained in this study indicated that the presence of DCPD layer-coated on β-TCP granular helps to improve osteoclast cells response that contribute in stimulating new bone formation.

Mesoporous Bioactive Glass Scaffold Delivers Salvianolic Acid B to Promote Bone Regeneration in a Rat Cranial Defect Model

Mesoporous Bioactive Glass (MBG) has been widely studied because of its excellent histocompatibility and degradability. However, due to the lack of good osteoinductive activity, the pure MBG scaffold is not effective in repairing large-scale bone defects. To observe the repair effect of MBG scaffolds delivering Salvianolic acid B (SB) on critical bone defects in rats. In this study, MBG scaffolds were used as delivery vehicle. SB, a small molecular active drug with good osteogenic differentiation ability, was loaded into the MBG scaffolds at low, medium and high doses. The effect of SB released from the MBG scaffolds on osteogenic differentiation of rat Bone Marrow Mesenchymal Stem Cells (rBMSCs) was investigated using alkaline phosphatase staining, alizarin red staining and real-time quantitative polymerase chain reaction. Moreover, 8 weeks after implantation of the scaffolds, the bone regeneration was evaluated by micro- CT, sequential fluorescence labeling and histological staining analysis. The in vitro results showed that different doses of SB had similar release rate from scaffolds and could be released from scaffolds continuously. The middle dose (MBG/MSB) and high dose (MBG/HSB) groups significantly promoted the osteogenic differentiation of rBMSCs when compared with a low dose (MBG/LSB) group. Moreover, SB produced significant increases in newly formed bone of calvarial bone defects in rats. It is concluded that the use of MBG scffolds delivering SB is an effective strategy for the treatment of bone defects.

Efficacy of bone formation of microporous sphere-shaped biphasic calcium phosphate in a rabbit skull bone defect model.

Bone graft is required in various surgical procedures. Although autograft is the gold standard, it has limited availability. Various compounds have been proposed as alternatives such as biphasic calcium phosphate (BCP), which is the most widely used compound. The newly synthesized microporous sphere-shaped BCP has the advantage of increasing contact surface, and it can induce the formation of microbone structures. A putty-type contains the addition of a fluid carrier to the sphere-shaped BCP and can be easily used for a small orifice large bone defect. To compare the widely used BCP products, new bone formation and residual graft materials (RGM) were evaluated for 6 and 12 weeks in a rabbit calvarial bone defect model. Although existing BCP products and the microporous sphere-type product did not differ significantly with respect to new bone formation and RGM, the putty-type product was largely washed out and had low new bone formation at 6 and 12 weeks. Overall, the results suggest that microporous sphere-shaped BCP showed similar bone formation capability to existing products and was able to maintain higher initial mechanical stability.

Effects of alloplastic graft material combined with a topical ozone application on calvarial bone defects in rats.

This study presents the evaluation of the damage in the bone tissue resulting from a calvarial defect in rats and the efficiency of exposure to an ozone application with an alloplastic bone graft on the calvarial bone damage. Wistar male rats (n = 56) were divided into four groups: a control group (n = 14), defect and ozone group (n = 14), defect and graft group (n = 14), and defect, graft, and ozone group (n = 14). Under anaesthesia, a circular full-thickness bone defect was created in all groups, and the experimental groups were further divided into two sub-groups, with 7 rats in each group sacrificed at the end of the 4th and 8th weeks. Bone samples were dissected, fixed in 10% formalin solution, and decalcified with 5% ethylene-diamine-tetraacetic acid (EDTA). After the routine follow-up on tissues, immunostaining of osteopontin and osteonectin antibodies was applied to sections and observed under a light microscope. The control group exhibited osteopontin and osteonectin expression in fibroblasts and inflammatory cells at the end of the 4th week with an acceleration at the 8th week. Ozone administration elucidated new trabecular bone formation by increasing osteoblastic activity. Lastly, our observations underscore that a combination of allograft and ozone application increased the osteoblast, osteocyte, and bone matrix development at the 4th and 8th weeks. Exposure to an ozone application with an alloplastic bone graft on calvarial bone damage may induce osteoblastic activity, matrix development, mature bone cell formation, and new bone formation in rats.

Transmission Electron Microscopic Examination of the Healing Power Effect of Milled Teeth Versus Beta- Tri Calcium Phosphate Grafted in Calvarial Bone Defect in Rats.

Objectives: to evaluate the effect of milled teeth versus beta tricalcium phosphate bone graft material on new bone formation at the cell level using transmission electron microscope Materials and methods: Forty-five adult male albino rats, were divided into three main groups (n=15); control and two experimental groups. Under general anesthesia, 1.5 cm incision was done exposing the cranial bone. Then two noncritical size bone defects were created one in each parital sides of the rat calvarial bone. In Group I (control group): the bilateral calvarial bony defects were left to heal spontaneously. In Group II the bilateral calvarial bony defects completely filled with β-TCP. In Group III: the bilateral calvarial bony defects completely filled with tooth ash. Five rats from each group were sacrificed after 7, 15, and 30 days postoperatively. Results: tooth ash group: showed more new bone formation. Different types of cells appeared more active: multiple lymphocytes, fibroblast, osteoprogenitor cells, osteoblasts. Multinucleated osteoclasts with prominent vacuolated cytoplasm and ruffled border in Howship’s lacunae were clearly seen. At day 30, disappearing of the tooth ash and infiltration of different types of cells; osteoprogenitor cells, bone lining cells, and osteoblasts while β-TCP particles were still seen in the sections. Conclusion: Bone activity, formation and maturity were ahead in tooth ash filled calvarial bony defects. Tooth ash had a role in the stimulation of osteoblastic activity in matrix formation and its mineralization.