Papers by Keyword: Bone Regeneration

Abstract: Bone microstructure is dominantly composed of anisotropic extracellular matrix (ECM) in which collagen fibers and epitaxially-oriented biological apatite (BAp) crystals are preferentially aligned depending on the bone anatomical position, resulting in exerting appropriate mechanical function. The regenerative bone in bony defects is however produced without the preferential alignment of collagen fibers and the c-axis of BAp crystals, and subsequently reproduced to recover toward intact alignment. Thus, it is necessary to produce the anisotropic bone-mimetic tissue for the quick recovery of original bone tissue and the related mechanical ability in the early stage of bone regeneration. Our group is focusing on the methodology for regulating the arrangement of bone cells, the following secretion of collagen and the self-assembled mineralization by oriented BAp crystallites. Cyclic stretching in vitro to bone cells, principal-stress loading in vivo on scaffolds, step formation by slip traces on Ti single crystal, surface modification by laser induced periodic surface structure (LIPSS), anisotropic collagen substrate with the different degree of orientation, etc. can dominate bone cell arrangement and lead to the construction of the oriented ECM similar to the bone tissue architecture. This suggests that stress/strain loading, surface topography and chemical anisotropy are useful to produce bone-like microstructure in order to promote the regeneration of anisotropic bone tissue and to understand the controlling parameters for anisotropic osteogenesis induction.

Abstract: Bone tissue in ideal conditions morphofunctional remodeling properly. The bone can be affected by fractures, tumors, hormonal dysfunction, senescence, genetic modifications, among others. In such circumstances, the proper diet, drug use, exercise and other factors are important to the prevention of bone mineral loss. The effect of kinesiotherapy obtained through the application of vibratory waves administered through the vibrating platform, Juvent1000 ® already been established in the prevention of bone mineral density, muscular trophism, among other systems in humans. The response by analyzing bone tissue of bone repair in critical defect is not known in experimental animals and in human clinical. This research evaluated the osteogenic potential critical defect in the calvaria of rats subjected to the application of vibratory waves obtained by vibrating platform and implant in the critical defect of rat calvaria. The bone tissue response was evaluated showed satisfactory results obtained in biological points 15, 45 and 120 days.

Abstract: Hydroxyapatite (HA) scaffold was fabricated using template method. Secondary phase of poly (ε-caprolactone) (PCL) was then introduced into the porous structure of the HA scaffold by the freeze drying method or the room drying process. Compression test and SEM were done to examine the mechanical properties and the microstructural morphology of the composite scaffolds. It was found that the compressive strength and modulus tend to increase with increasing PCL concentration. HA/PCL scaffolds fabricated under the room drying process exhibited higher compression strength and modulus than HA/PCL scaffolds prepared by the freeze drying method because the porous HA surfaces were completely covered by PCL in the room drying scaffolds. XRD test was also used to study the phase stability of the scaffolds. It was confirmed that there was no chemical reaction between PCL and HA. On overall, the results indicated that the introduction of secondary PCL phases into the porous HA scaffold can improve the low strength and toughness of the pure HA scaffold and the HA/PCL composite scaffolds might be a potential candidate in bone tissue engineering.

Abstract: The aim of the described study was to generate and evaluate a putty-like bone graft substitute ready to use for dental and orthopedic surgery. According to the asking of clinicians the new material should avoid the necessity of mixing blood and bone graft during the surgical process. Therefor the granulous material NanoBone^® has been combined with a hydrogel based on Polyvinylpyrrolidone (PVP) and tested in standardized rat tibia defect over a period of 12 weeks and evaluated histologically. The results showed no limitations of the granulate characteristics in matrix change and hence a high level of vascularization and bone formation. An example for dental application shows the outcome in the case of socket preservation.

Abstract: Hydroxyapatite, (Ca₁₀(PO₄)₆(OH)₂ is chemically similar to the mineral component of bones and teeth. HAp is among of the few materials that are classified as bioactive, meaning that it will support bone ingrowth and osseointegration when used in orthopaedic, dental and maxillofacial applications. Hydroxyapatite may be employed in forms such as powders, porous blocks and hybrid composites to fill bone defects or voids. These may arise when large sections of bone have had to be removed or when bone augmentations are required (e.g. dental applications). In this work, nanohydroxyapatite (nanoHAp) was successfully produced by using recycled eggshell and phosphoric acid by mechanochemical activation method (e.g. attrition milling). nanoHAp bioactivity was evaluated in animal (rabbit) models. Sixteen 4-month-old New Zealand white rabbits with an average weight of 2.8kg were used in experiments. After bilateral parietal bony defects formation (diameter: 8.0mm), nanoHAp was grafted. The control was unfilled defect. The bone regeneration was evaluated by micro-computerized tomograms (μCT) and histomorphometric analysis at 4 and 8 weeks. In conclusion, nanoHAp from eggshell showed much more bone formation compared to unfilled control group in both μCT analysis and histomorphometric analysis. Considering that the eggshell is easily available and cheap, nanoHAp from the eggshell can be good calcium source in tissue engineering.

Abstract: It was reported that one-dimensionally elongated pores in implants promote the production of new bone tissue possessing both high bone density and the preferential alignment of biological apatite (BAp) c-axis/collagen as a bone quality parameter. This finding indicates that the anisotropic orientation and/or migration of osteoblasts guided by the grooved-pore surface affected the establishment of the anisotropic microstructure of bone tissue. In this study, a grooved polytetrafluoroethylene (Teflon) implant, which may have a role in regulating osteoblast arrangement, was prepared to investigate the relationship between cell behavior and bone microstructure. A cylindrical Teflon implant with 8 grooves on its side was prepared. The width and depth of the groove cross-section were 0.5 and 0.75 mm, respectively. Each implant was inserted in a drill-hole defect created on a rabbit femur such that the groove direction was parallel or perpendicular to the long bone axis in which the BAp c-axis aligns one-dimensionally. The Young’s modulus of Teflon is approximately 0.5 GPa, much lower than that of bone; therefore, the effects of applied stress can be eliminated in this model. The oriented new bone was preferentially produced along the grooved surface. The alignment direction of the BAp c-axis was almost parallel to the grooved surface even near the surface vertically aligned to the long bone axis. The geometry of the implant surface can control the organization of BAp alignment through the arrangement of osteoblasts to orient and subsequently to migrate along the surface direction; hence, implant geometry, particularly the groove, is considered an important factor controlling the BAp orientation of regenerated bone tissues.

Abstract: This manuscript discusses peri-implantitis around dental implants and the current methodologies of surgical and non-surgical approaches towards treating peri-implantitis. Mechanical, chemical cleansing and reactivation of infected implant surface along with recent advances like the use of Laser and Photodynamic therapy (PDT) have also been reviewed in this literature. Bone regenerative treatment methods for the treatment of peri-implantitis using non-resorbable membranes (Guided Bone Regeneration), autogenous bone grafts and bone substitute materials with recombinant human bone morphogenetic protein-2 (rhBMP-2) and other growth factors have also been reviewed in this manuscript.

Abstract: This study is focused on the development of clinically applicable nanocarriers for bone regeneration by establishing a systematic modeling guided nanocarriers development methodology. Firstly a drug release model is built through different release mechanisms to predict the profiles of drugs released from nanospheres. Then a cell response model is built through multiple signaling pathways related to the released drugs to predict the relationship between the drug profiles and the terminal cell phenotypes. Finally the cell response model combined with the drug release model will be employed to optimally predict the relationship between the input and output of the complete model, to establish an entire system with tunable input and output, and finally by optimal control to guide and accelerate the design of the BMP-2 and vancomycin incorporated nanocarriers.

Abstract: Natural bone is a composite mainly made from nano/micro-structure of hydroxyapatite and collagen fibers. For bone regeneration by tissue engineering, it is important to synthesize three dimension nano-composites with good biocompatibility, high bioactivity and great bonding property as potentially useful scaffold. In this study, we fabricated chitosan nano-nonwoven scaffold via electrospinning and modified chitosan scaffolds by carboxymethylation (CM) to improve the osteoconductive characteristics. Results of FTIR confirmed the existence of carboxymethyl groups of CMChitosan. Moreover by employed mice osteoblast (MC3T3-E1) cell for adhesion, proliferation and differentiation assays, we found that CMChitosan appeared to have effect on the late stages of osteoblast behavior (calcium deposit).

Abstract: Bony defects caused by periodontitis are often treated by regenerative therapy using autografts and/or allografts. Alloplasts such as hydroxyapatite or ceramics and bioactive glasses are used as osteoconductive materials that serve as scaffold for new bony ingrowth. The purpose of this study was to ascertain the possible regenerative capability of glass reinforced hydroxyapatite (Bonelike¬)¬¬¬ an osteoconductive synthetic graft in the treatment of human periodontal intrabony angular defects. The material was placed in 2 defects in 2 individual patients and clinical parameters such as probing depth (PD) and clinical attachment level (CAL) have been included. Bone fill was determined using an intra oral periapical radiograph (IOPA) and Autocad Software. After 3 months implantation period, there was an improvement in CAL and reduction in PD along with bone fill was observed.