Effect of a synthetic hydroxyapatite-based bone grafting material compared to established bone substitute materials on regeneration of critical-size bone defects in the ovine scapula.

Lately, the potential risk of disease transmission due to the use of bovine-derived bone substitutes has become obvious, demonstrating the urgent need for a synthetic grafting material with comparable bioactive behaviour and properties. Therefore, the effect of a synthetic hydroxyapatite (HA) (Osbone) bone grafting material on bone regeneration was evaluated 2 weeks, 1 month, and 3, 6, 12 and 18 months after implantation in critical-size bone defects in the ovine scapula and compared to that of a bovine-derived HA (Bio-Oss) and β-tricalcium phosphate (TCP) (Cerasorb M). New bone formation and the biodegradability of the bone substitutes were assessed histomorphometrically.

Osteogenic Effect of a Bioactive Calcium Alkali Phosphate Bone Substitute in Humans.

(1) Background: The desire to avoid autograft harvesting in implant dentistry has prompted an ever-increasing quest for bioceramic bone substitutes, which stimulate osteogenesis while resorbing in a timely fashion. Consequently, a highly bioactive silicon containing calcium alkali orthophosphate (Si-CAP) material was created, which previously was shown to induce greater bone cell maturation and bone neo-formation than β-tricalcium phosphate (β-TCP) in vivo as well as in vitro. Our study tested the hypothesis that the enhanced effect on bone cell function in vitro and in sheep in vivo would lead to more copious bone neoformation in patients following sinus floor augmentation (SFA) employing Si-CAP when compared to β-TCP.

A tissue engineered 3D printed calcium alkali phosphate bioceramic bone graft enables vascularization and regeneration of critical-size discontinuity bony defects .

Recently, efforts towards the development of patient-specific 3D printed scaffolds for bone tissue engineering from bioactive ceramics have continuously intensified. For reconstruction of segmental defects after subtotal mandibulectomy a suitable tissue engineered bioceramic bone graft needs to be endowed with homogenously distributed osteoblasts in order to mimic the advantageous features of vascularized autologous fibula grafts, which represent the standard of care, contain osteogenic cells and are transplanted with the respective blood vessel. Consequently, inducing vascularization early on is pivotal for bone tissue engineering.

Differences in Cell-Intrinsic Inflammatory Programs of Yolk Sac and Bone Marrow Macrophages.

Background: Tissue-resident macrophages have mixed developmental origins. They derive in variable extent from yolk sac (YS) hematopoiesis during embryonic development. Bone marrow (BM) hematopoietic progenitors give rise to tissue macrophages in postnatal life, and their contribution increases upon organ injury.

Dual local drug delivery of vancomycin and farnesol for mitigation of MRSA infection in vivo - a pilot study.

Surgical site infections after orthopaedic surgery using fracture fixation devices or endosseous implants create major surgical challenges with severe adverse effects, such as osteomyelitis. These infections are frequently caused by Staphylococcus aureus, often with high resistance to antibiotics, such as methicillin-resistant Staphylococcus aureus (MRSA). Due to the formation of impenetrable biofilms on implant surfaces, systemic antibiotic treatment has become exceedingly difficult.

Effect of silicon-doped calcium phosphate bone grafting materials on bone regeneration and osteogenic marker expression after implantation in the ovine scapula.

Compared to the currently clinically available bone grafting materials for alveolar ridge augmentation, there is a great demand for bioactive bone substitutes with higher resorbability, which enhance osteogenesis at the same time. This has prompted the development of a silicon-doped rapidly resorbable calcium alkali orthophosphate (Si-CAOP) and silicon-doped β-tricalcium phosphate (Si-TCP). This study evaluated the effect of these two particulate graft materials as compared to the currently clinically used β-TCP on bone formation and osteogenic marker expression after 2 weeks, 1, 3, 6, 12, and 18 months of implantation in critical size defects in the sheep scapula.

Effect of a Particulate and a Putty-Like Tricalcium Phosphate-Based Bone-grafting Material on Bone Formation, Volume Stability and Osteogenic Marker Expression after Bilateral Sinus Floor Augmentation in Humans.

This study examines the effect of a hyaluronic acid (HyAc) containing tricalcium phosphate putty scaffold material (TCP-P) and of a particulate tricalcium phosphate (TCP-G) graft on bone formation, volume stability and osteogenic marker expression in biopsies sampled 6 months after bilateral sinus floor augmentation (SFA) in 7 patients applying a split-mouth design. 10% autogenous bone chips were added to the grafting material during surgery. The grain size of the TCP granules was 700 to 1400 µm for TCP-G and 125 to 250 µm and 500 to 700 µm (ratio 1:1) for TCP-P.

Effect of sex-hormone levels, sex, body mass index and other host factors on human craniofacial bone regeneration with bioactive tricalcium phosphate grafts.

Little is known regarding the associations between sex-hormone levels, sex, body mass index (BMI), age, other host factors and biomaterial stimulated bone regeneration in the human craniofacial skeleton. The aim of this study was to elucidate the associations between these factors and bone formation after sinus floor augmentation procedures (SFA) utilizing a bioactive tricalcium phosphate (TCP) bone grafting material. We conducted a prospective study in a human population in which 60 male and 60 female participants underwent SFA and dental implant placement using a staged approach.

Development of a synthetic tissue engineered three-dimensional printed bioceramic-based bone graft with homogenously distributed osteoblasts and mineralizing bone matrix in vitro.

Over the last decade there have been increasing efforts to develop three-dimensional (3D) scaffolds for bone tissue engineering from bioactive ceramics with 3D printing emerging as a promising technology. The overall objective of the present study was to generate a tissue engineered synthetic bone graft with homogenously distributed osteoblasts and mineralizing bone matrix in vitro, thereby mimicking the advantageous properties of autogenous bone grafts and facilitating usage for reconstructing segmental discontinuity defects in vivo. To this end, 3D scaffolds were developed from a silica-containing calcium alkali orthophosphate, using, first, a replica technique - the Schwartzwalder-Somers method - and, second, 3D printing, (i.

Novel silk protein barrier membranes for guided bone regeneration.

This study assesses the biocompatibility of novel silk protein membranes with and without modification, and evaluates their effect on facilitating bone formation and defect repair in guided bone regeneration. Two calvarian bone defects 12 mm in diameter were created in each of a total of 38 rabbits. Four different types of membranes, (silk-, hydroxyapatite-modified silk-, β-TCP-modified silk- and commonly clinically used collagen-membranes) were implanted to cover one of the two defects in each animal.

Percutaneous external fixator pins with bactericidal micron-thin sol-gel films for the prevention of pin tract infection.

Risk of infection is considerable in open fractures, especially when fracture fixation devices are used to stabilize the fractured bones. Overall deep infection rates of 16.2% have been reported.

3D-printed silicate porous bioceramics using a non-sacrificial preceramic polymer binder.

Silicate bioceramics possess an excellent bioactivity; however, shaping them into complex geometries is still challenging. Therefore, this paper aims to present a new strategy for the shaping of a bioglass-ceramic with controlled geometry and properties starting from a glass powder combined with a preceramic polymer, i.e.

Rat animal model for preclinical testing of microparticle urethral bulking agents.

Objectives: To develop an economic, practical and readily available animal model for preclinical testing of urethral bulking therapies, as well as to establish feasible experimental methods that allow for complete analysis of hard microparticle bulking agents.

Methods: Alumina ceramic beads suspended in hyaluronic acid were injected into the proximal urethra of 15 female rats under an operating microscope. We assessed overall lower urinary tract function, bulking material intraurethral integrity and local host tissue response over time.

Bactericidal micron-thin sol-gel films prevent pin tract and periprosthetic infection.

Orthopedic injuries constitute the majority of wounds sustained by U.S. soldiers in recent conflicts.

Performance of β-tricalcium phosphate granules and putty, bone grafting materials after bilateral sinus floor augmentation in humans.

Sinus floor augmentation (SFA) using bone grafting materials, and in particular calcium phosphates (CaP), is a well-established pre-implantology procedure. The use of CaP simplifies SFA procedures. β-tricalcium phosphate (β-TCP) is amply used for SFA.

Sol-gel silica controlled release thin films for the inhibition of methicillin-resistant Staphylococcus aureus.

The incidence of methicillin-resistant Staphylococcus aureus (MRSA) infection has significantly increased. Generally, the success of this bacterium as a pathogen is attributed to its ability to adhere to surfaces and remain there, under the protection of an extracellular matrix known as biofilm. To combat MRSA with regular doses of vancomycin, efforts are continuously underway to increase its effectiveness.

Quantification of bone tissue regeneration employing beta-tricalcium phosphate by three-dimensional non-invasive synchrotron micro-tomography--a comparative examination with histomorphometry.

Purpose: This methodical study presents a novel approach to evaluate the validity of two-dimensional histomorphometric measurements of a bone biopsy specimen after sinus floor elevation by means of high contrast, high resolution, three-dimensional and non-destructive synchrotron micro-tomography (SCT). The aim of this methodical description is to demonstrate the potential of this new approach for the evaluation of bone biopsy samples.

Materials And Methods: Unilateral sinus grafting was carried out exemplarily in two patients using a combination of beta-tricalcium phosphate (beta-TCP) and autogenous bone chips.

Biological response to micron- and nanometer-sized particles known as potential wear products from artificial hip joints: Part II: Reaction of murine macrophages to corundum particles of different size distributions.

Macrophages play a pivotal role in tissue reaction and immune response. They recognize, phagocytose particles and generate cytokines to influence local cellular reactions. Friction and wear of implant components usually generates microparticles (MP) in a size range of 1-10 mum and nanoparticles (NP) in the range of 10-1000 nm.

Biological response to micron- and nanometer-sized particles known as potential wear products from artificial hip joints: Part I: Selection and characterization of model particles.

The aim of this work was to select and characterize model particles, which correspond to real wear products from artificial hip joints, and to investigate the dispersing behavior of these powders. Commercially available nano and microparticles of corundum, graphite, and chromium oxide were selected or alternatively self-produced by milling. These powders were characterized regarding density, specific surface area, crystalline phases, particle size distributions and shape.

Effect of beta-tricalcium phosphate particles with varying porosity on osteogenesis after sinus floor augmentation in humans.

This study examines the effect of two beta-tricalcium phosphate (TCP) particulate bone grafting materials with varying porosity on bone formation and on osteogenic marker expression 6 months after sinus floor augmentation. Unilateral sinus grafting was performed in 20 patients using a combination (4:1 ratio) of beta-TCP particles with 35% porosity (TCP-C) or 65% porosity (TCP-CM) and autogenous bone chips. At implant placement cylindrical biopsies were sampled and processed for immunohistochemical analysis of resin embedded sections.

Degradation of 24S-hydroxycholesterol in men is not regulated by CYP7A1.

Objective: The conversion of cholesterol into bile acids occurs via a long cascade of enzymatically regulated oxidative processes. Our aim was to examine if an up-regulation of hepatic cholesterol 7alpha-hydroxylase (CYP7A1) in humans by cholestyramine, a bile acid-binding resin, has an effect on the degradation of brain-specific 24S-hydroxycholesterol.

Patients And Methods: Six normocholesterolemic male volunteers received 4 g cholestyramine b.

Effect of rapidly resorbable bone substitute materials on the temporal expression of the osteoblastic phenotype in vitro.

Ideally, bioactive ceramics for use in alveolar ridge augmentation should possess the ability to activate bone formation and, thus, cause the differentiation of osteoprogenitor cells into osteoblasts at their surfaces. Therefore, in order to evaluate the osteogenic potential of novel bone substitute materials, it is important to examine their effect on osteoblastic differentiation. This study examines the effect of rapidly resorbable calcium-alkali-orthophosphates on osteoblastic phenotype expression and compares this behavior to that of beta-tricalcium phosphate (TCP) and bioactive glass 45S5.

Anodic cell-protein deposition on inverse inkjet printed micro structured gold surfaces.

The transformation of fibrinogen into fibrin is biologically activated in a complex multi-step process known as the coagulation cascade. This transformation can also be triggered by anodic surfaces. It has been suggested that this mechanism is a result of an electron transfer from the anode to the fibrinogen molecule resulting in the formation of fibrin.

A method for immunohistochemical detection of osteogenic markers in undecalcified bone sections.

To evaluate the osteogenic potential of novel implant materials, it is important to examine their effect on osteoblastic differentiation. Characterizing the tissue response at the bone-biomaterial interface in vivo at a molecular level would contribute significantly to enhancing our understanding of tissue integration of endosseous implant materials. We describe here a new technique that overcomes difficulties commonly associated with performing immunohistochemistry on undecalcified sawed sections of bone.

Growth factor expression following clinical mandibular distraction osteogenesis in humans and its comparison with existing animal studies.

Aim: Lengthening the mandible by distraction osteogenesis (DO) is nowadays a well recognized technique in maxillofacial surgery. In this study growth factor expression profiles were examined in biopsies taken from six patients undergoing mandibular DO and compared with findings from a sheep model for mandibular DO.

Study Design: In all patients (and sheep), the ascending ramus was distracted 10-15 mm at a rate of 1mm/day using an intraoral device.