Stability of Implants Supported By Three Types of Bone Grafting Materials in Dogs

Background: This study was conducted to assess the stability of implants placed in a simultaneous procedure with different grafting materials (autogenous, xenogenous, and synthetic) in experimentally induced bone defects in dogs.Methods: Thirteen dogs were included and divided into three groups according to the time of sacrificing. Oversized osteotomies were prepared in the sternum, and the implants were placed in bone defects. A total of 3 to 5 implants were placed per animal. Each group of animals contained 3 subgroups according to the grafting material utilized. In subgroup 1, autograft was applied, whereas in subgroups 2 and 3, bovine bone mineral (Cerabone) and a synthetic calcium phosphate substitute (Osteon II) were employed. At the end of the specified healing periods (2 months, 4 months, or 6 months), the animals were sacrificed and the implant stability was determined through measuring the resonance frequency.Results: Forty-five integrated implants were obtained from this study and nine were lost (failure rate 17%). The two-way analysis of variance revealed no significant difference in ISQ measurements either between the bone graft materials (autogenous, xenogenous, and synthetic; P=0.950) or between the healing intervals (2 months, 4 months, and 6 months; P=0.769)Conclusions: The stability of implants augmented with autogenous, xenogenous (Cerabone) or synthetic (Osteon II) graft materials was comparable at 2, 4 and 6 months after placement. This indicates that both Cerabone and Osteon II could be considered as suitable substitutes for regeneration of bone defects to overcome the limitations of autografts.

Radiation-Induced Stable Radicals in Calcium Phosphates: Results of Multifrequency EPR, EDNMR, ESEEM, and ENDOR Studies

This article presents the results of a study of radiation-induced defects in various synthetic calcium phosphate (CP) powder materials (hydroxyapatite—HA and octacalcium phosphate—OCP) by electron paramagnetic resonance (EPR) spectroscopy at the X, Q, and W-bands (9, 34, 95 GHz for the microwave frequencies, respectively). Currently, CP materials are widely used in orthopedics and dentistry owing to their high biocompatibility and physico-chemical similarity with human hard tissue. It is shown that in addition to the classical EPR techniques, other experimental approaches such as ELDOR-detected NMR (EDNMR), electron spin echo envelope modulation (ESEEM), and electron-nuclear double resonance (ENDOR) can be used to analyze the electron–nuclear interactions of CP powders. We demonstrated that the value and angular dependence of the quadrupole interaction for 14N nuclei of a nitrate radical can be determined by the EDNMR method at room temperature. The ESEEM technique has allowed for a rapid analysis of the nuclear environment and estimation of the structural positions of radiation-induced centers in various crystal matrices. ENDOR spectra can provide information about the distribution of the nitrate radicals in the OCP structure.

Nanotechnology and Nanoparticles in Contemporary Sciences

Nonotechanology has been a rapidly growing field of advanced science at the inception of this century. Many problematic endeavours in sciences have been successfully overcome using nanoparticles. For example, a low risk solution using antibody modified bismuth nanoparticle, in combination with an X-ray dose equivalent to a chest X-ray specifically, has been shown to kill the common bacterium Pseudomonas aeruginosa in a set up designed to resemble a deep wound in human tissue. Nanosized gold particle could catalyse the oxidation of carbon monoxide better than anything previously known. Heparin functionalized nanoparticles have been use for targeted delivery of anti-malarial drugs. Heparin is abundant and cheap compared to treatments that involve antibodies, an important consideration, since malaria is most common in developing countries. A bone repairing nano-particle paste has been developed that promises faster repair of fractures and breakages. DNA containing two growth genes is encapsulated inside synthetic calcium phosphate nanoparticles. In a remarkable demonstration of the extreme limits of nanoscale engineering, researchers have used the tip of a scanning tunnelling microscope to cleave and form selected chemical bonds in a complex molecule. Many medicinal and industrial endeavours have seen the use of Nanotechnology. These and other more recent advances in nanotechnology will be presented at this conference

APPLICATION OF BIOGLASS IN THE TREATMENT OF FRACTURES AND DEFECTS OF LONG BONES

One of the most promising trends in contemporary traumatology and orthopaedics towards the treatment of fractures and bone defects is the use of synthetic calcium-phosphate biomaterials. The purpose of this study is to identify the features of bone defect healing in rats during the implantation of calcium phosphate glass crystalline materials, and to substantiate the feasibility of the use of bioglass in the clinical treatment of fractures and defects of long bones. Materials and methods. In this study we used bioactive calcium-phosphate glass crystal material BS-11. The experimental part was performed on 36 white rats. The animals were subjected to defect modelling in the femur with following bioglass filling. Results. We observed the formation of osteogenic fibroreticular tissue and bone tissue of varying degrees of maturity around the implanted filling samples through all the healing periods. The relative content of bone tissue in the surrounding regenerated tissue around the studied samples BS-11 increased in parallel with the increase of the observation period and reached 100% in 30 days after the surgical operation and at the end of the study we registered the formation of bone tissue of the lamellar structure around the samples inserted. We observed no signs of inflammation or any cellular reaction in any of the cases studies that points out the biocompatibility of the material. Conclusions. Morphological study has demonstrated that the insertion of cylindrical blocks made of glass-crystalline calcium phosphate materials BC-11 in the distal metaphysis of the femur of rats and healing is accompanied with osteoregeneration around them in accordance with the conventional stages of the bone tissue formation. This material can be recommended for treating long bone defects of different aetiology.

Subchondroplasty of the Ankle and Hindfoot for Treatment of Osteochondral Lesions and Stress Fractures: Initial Imaging Experience

Objective:To describe the imaging findings of patients treated with subchondroplasty (SCP) of the ankle and hindfoot. Materials and Methods: Eighteen patients (10 men, 8 women; age mean 43.1 years [range 20.1-67.7 years]) underwent ankle and hindfoot SCP at a single center over a 14-month period. Imaging data were reviewed retrospectively by 2 radiologists by consensus interpretation, including preoperative radiography (18), computed tomography (CT) (11), and magnetic resonance imaging (MRI) (13) and postoperative radiography (10), CT (4), and MRI (6). Follow-up imaging was acquired 1 month to 1.6 years following SCP. Results: Indications for SCP included symptomatic bone marrow lesions (BMLs) secondary to an osteochondral lesion (OCL) (16/18) or stress fracture (2/18). While focal radiodensity related to the SCP procedure was retrospectively identifiable on postoperative radiography in all except 1 case (10/11), postprocedural findings were not described by the interpreting radiologist in 6/11 cases. On CT, the average injected synthetic calcium phosphate (CaP) volume was 1.15 cm3 (SD = 0.33 cm3); mean CT attenuation of the injectate was 1220 HU (range 1058-1465 HU). In all patients who had pre- and postoperative MRI (5/18), BML size decreased on follow-up MRI. Extra-osseous extrusion of CaP was not seen on postoperative radiography, CT, or MRI. Conclusion: Physicians should be aware of the expanding preoperative indications and postoperative imaging findings of SCP, which is being performed with increasing frequency in the ankle and hindfoot. Levels of Evidence: Diagnostic, Level III: Retrospective cohort study