Treatment of a mandibular cyst before implant placement: case report [Case Report]
The aim of this case study is to present a clinical approach to treatment of a mandibular intrabony cyst employing guided bone regeneration principles and protection of the mandibular nerve prior to implant placement. A treatment approach employing a combination of grafting materials and membranes was used to treat the cyst and protect the mandibular nerve prior to implant placement. Micro CT, as well as histology and histomorphometrics, was used to evaluate treatment outcomes. Histological inspection showed bone regeneration at the grafting site. Histomorphometric analysis of the biopsy core rendered a total bone percent area of 58.87% and 41.13% soft tissue. Out of the total bone percent area, 90.45% was revealed as vital bone and 9.55% was graft remnant. The grafted area is supporting an implant-supported prosthesis in full function.
Development of a guided bone regeneration device using salicylic acid-poly(anhydride-ester) polymers and osteoconductive scaffolds
Successful repair of craniofacial and periodontal tissue defects ideally involves a combined therapy that includes inflammation modulation, control of soft tissue infiltration, and bone regeneration. In this study, an anti-inflammatory polymer, salicylic acid-based poly(anhydride-ester) (SAPAE) and a three-dimensional osteoconductive ceramic scaffold were evaluated as a combined guided bone regeneration (GBR) system for concurrent control of inflammation, soft tissue ingrowth, and bone repair in a rabbit cranial defect model. At time periods of 1, 3, and 8 weeks, five groups were compared: (1) scaffolds with a solid ceramic cap (as a GBR structure); (2) scaffolds with no cap; (3) scaffolds with a poly(lactide-glycolide) cap; (4) scaffolds with a slow release SAPAE polymer cap; and (5) scaffolds with a fast release SAPAE polymer cap. Cellular infiltration and bone formation in these scaffolds were evaluated to assess inflammation and bone repair capacity of the test groups. The SAPAE polymers suppressed inflammation and displayed no deleterious effect on bone formation. Additional work is warranted to optimize the anti-inflammatory action of the SAPAE, GBR suppression of soft tissue infiltration, and stimulation of bone formation in the scaffolds and create a composite device for successful repair of craniofacial and periodontal tissue defects. (c) 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 655-664, 2014.
The influence of atmospheric pressure plasma surface-modified polymers PVDF, ECTFE, and PEEK on primary mesenchymal stem cell response
[S.l. : s.n.], 2014
Antibacterial Activity of As-Annealed TiO2 Nanotubes Doped with Ag Nanoparticles against Periodontal Pathogens
It is important to develop functional transmucosal implant surfaces that reduce the number of initially adhering bacteria and they need to be modified to improve the anti-bacterial performance. Commercially pure Ti sheets were anodized in an electrolyte containing ethylene glycol, distilled water and ammonium fluoride at room temperature to produce TiO2 nanotubes. These structures were then annealed at 450 degrees C to transform them to anatase. As-annealed TiO2 nanotubes were then treated in an electrolyte containing 80.7 g/L NiSO4 .7H2O, 41 g/L MgSO4 .7H2O, 45 g/L H3BO3, and 1.44 g/L Ag2SO4 at 20 degrees C by the application of 9 V AC voltage for doping them with silver. As-annealed TiO2 nanotubes and as-annealed Ag doped TiO2 nanotubes were evaluated by SEM, FESEM, and XRD. Antibacterial activity was assessed by determining the adherence of A. actinomycetemcomitans, T. forsythia, and C. rectus to the surface of the nanotubes. Bacterial morphology was examined using an SEM. As-annealed Ag doped TiO2 nanotubes revealed intense peak of Ag. Bacterial death against the as-annealed Ag doped TiO2 nanotubes were detected against A. actinomycetemcomitans, T. forsythia, and C. rectus indicating antibacterial efficacy.
3D conductive nanocomposite scaffold for bone tissue engineering
Bone healing can be significantly expedited by applying electrical stimuli in the injured region. Therefore, a three-dimensional (3D) ceramic conductive tissue engineering scaffold for large bone defects that can locally deliver the electrical stimuli is highly desired. In the present study, 3D conductive scaffolds were prepared by employing a biocompatible conductive polymer, ie, poly(3,4-ethylenedioxythiophene) poly(4-styrene sulfonate) (PEDOT:PSS), in the optimized nanocomposite of gelatin and bioactive glass. For in vitro analysis, adult human mesenchymal stem cells were seeded in the scaffolds. Material characterizations using hydrogen-1 nuclear magnetic resonance, in vitro degradation, as well as thermal and mechanical analysis showed that incorporation of PEDOT:PSS increased the physiochemical stability of the composite, resulting in improved mechanical properties and biodegradation resistance. The outcomes indicate that PEDOT:PSS and polypeptide chains have close interaction, most likely by forming salt bridges between arginine side chains and sulfonate groups. The morphology of the scaffolds and cultured human mesenchymal stem cells were observed and analyzed via scanning electron microscope, micro-computed tomography, and confocal fluorescent microscope. Increasing the concentration of the conductive polymer in the scaffold enhanced the cell viability, indicating the improved microstructure of the scaffolds or boosted electrical signaling among cells. These results show that these conductive scaffolds are not only structurally more favorable for bone tissue engineering, but also can be a step forward in combining the tissue engineering techniques with the method of enhancing the bone healing by electrical stimuli.
Why we cannot grow a human arm
There are several significant issues that prevent us from growing a human arm now, or within the next 10-20 years. From a tissue engineering perspective, while we can grow many of the components necessary for construction of a human arm, we can only grow them in relatively small volumes, and when scaled up to large volumes we lack the ability to develop adequate blood/nerve supply. From a genetic engineering perspective, we will probably never be able to turn on the specific genes necessary to "grow an arm" unless it is attached to a fetus and this presents enormous ethical issues related to farming of human organs and structures. Perhaps the most daunting problem facing the transplantation of a tissue engineered or transplanted arm is that of re-innervation of the structure. Since the sensory and motor nerve cells of the arm are located outside of the structure, re-innervation requires those nerves to regenerate over relatively large distances to repopulate the nervous system of the arm. This is something with which we have had little success. We can grow repair parts, but "growing an arm" presents too many insurmountable problems. The best we could possibly do with tissue engineering or genetic engineering would be the equivalent of a fetal arm and the technical problems, costs, and ethical hurdles are enormous. A more likely solution is a functional, permanent, neuroelectronically-controlled prosthesis. These are nearly a reality today.
The Use Of Three-Dimensionally Printed beta-Tricalcium Phosphate/Hydroxyapatite To Understand The Regulation Of Adenosine Receptors In Osteoclast Formation and Promotion In Bone Regeneration [Meeting Abstract]
Repair of complex craniofacial bone defects using 3D-printed tricalcium phosphate scaffolds [Meeting Abstract]
Statement of the Problem: Repair of bone lost to trauma, disease, or birth defect requires regeneration of large volumes of structurally complex bone. Current bone repair methods, like bone grafts or particulate materials, are imperfect for repair of complex craniofacial defects which require formation of large amounts of natural, mechanically strong bone. 3D-printed, Direct Write (DW), scaffolds composed of tricalcium phosphate (TCP) with temporary calcium sulfate filler can serve as a better option to repair large complex bone defects. Such scaffolds are mechanically stable and can be custom printed to match the exact defect shape and size. Current literature debates scaffold pore sizes for optimal bone repair, stating scaffold pore size should be from 100-400mm. The objective of this study is to determine how pore size dictates the quality of ingrowing bone. Thiswill allow the design of scaffolds that can regenerate the natural architecture and mechanical properties of bone in complex craniofacial defects. Methods: Scaffold pores (spaces defined by struts) varied in all dimensions. Two 11mm diameter disk scaffold designs were DW printed of 15:85 HAP/b-TCP ink and filled with temporary calcium sulfate(CS) cement. These two designs allowed the study of pores from ~0-940 mm. The two scaffolds were placed symmetrically in bilateral trephine defects in the calvarias of 8 New Zealand white rabbits. Animals were sacrificed after 8 weeks (n=7) and 16 weeks (n=1). Bone ingrowth and remodeling rates of resected implants were quantified by microCT and hard tissue histology. Results: Contrary to previous literature findings, significant bone ingrowth occurred in pores ranging from 20mm to 940mm. Larger pore sizes allowed more bone ingrowth than smaller pore sizes. As pore size decreased, bone as a fraction of available space increased from 55%-85% and scaffold remodeling decreased from 32%-5%. Conclusions: This study demonstrated precision scaffold production where variable porosity scaffolds were used !
Socket Preservation and Sinus Augmentation Using a Medical Grade Calcium Sulfate Hemihydrate and Mineralized Irradiated Cancellous Bone Allograft Composite
Abstract Regeneration and preservation of bone after the extraction of a tooth is necessary for the placement of a dental implant. The goal is to regenerate alveolar bone with minimal postoperative pain. Medical grade calcium sulfate hemihydrate (MGCSH) can be used alone or in combination with other bone grafts; it improves graft handling characteristics and particle containment of particle-based bone grafts. In this case series a 1:1 ratio mix of MGCSH and mineralized irradiated cancellous bone allograft (MICBA) was mixed with saline and grafted into an extraction socket in an effort to maintain alveolar height and width for future implant placement. MGCSH can be used in combination with other bone grafts and can improve handling characteristics and graft particle containment of particle-based bone grafts. Based on the following cases, it was found that a MGCSH:MICBA graft can potentially be an effective bone graft composite. It has the ability to act as a space maintainer and as an osteoconductive trellis for bone cells, promoting bone regeneration in the extraction socket. MGCSH, a cost-effective option, successfully improved MICBA handling characteristics, prevented soft tissue ingrowth and assisted in the regeneration of bone
Characterization of Adipose-Derived Mesenchymal Stem Cell Combinations for Vascularized Bone Engineering
Since bone repair and regeneration depend on vasculogenesis and osteogenesis, both of these processes are essential for successful vascularized bone engineering. Using adipose-derived stem cells (ASCs), we investigated temporal gene expression profiles, as well as bone nodule and endothelial tubule formation capacities, during osteogenic and vasculogenic ASC lineage commitment. Osteoprogenitor-enriched cell populations were found to express RUNX2, MSX2, SP7 (osterix), BGLAP (osteocalcin), SPARC (osteonectin), and SPP1 (osteopontin) in a temporally specific sequence. Irreversible commitment of ASCs to the osteogenic lineage occurred between days 6 and 9 of differentiation. Endothelioprogenitor-enriched cell populations expressed CD34, PECAM1 (CD31), ENG (CD105), FLT1 (Vascular endothelial growth factor [VEGFR1]), and KDR (VEGFR2). Capacity for microtubule formation was evident in as early as 3 days. Functional capacity was assessed in eight coculture combinations for both bone nodule and endothelial tubule formation, and the greatest expression of these end-differentiation phenotypes was observed in the combination of well-differentiated endothelial cells with less-differentiated osteoblastic cells. Taken together, our results demonstrate vascularized bone engineering utilizing ASCs is a promising enterprise, and that coculture strategies should focus on developing a more mature vascular network in combination with a less mature osteoblastic stromal cell.