Proposal for a New Bioactive Kinetic Screw in an Implant, Using a Numerical Model

A new biomechanism, Bioactive Kinetic Screw (BKS) for screws and bone implants created by the first author, is presented using a bone dental implant screw, in which the bone particles, blood, cells, and protein molecules removed during bone drilling are used as a homogeneous autogenous transplant in the same implant site, aiming to obtain primary and secondary bone stability, simplifying the surgical procedure, and improving the healing process. The new BKS is based on complex geometry. In this work, we describe the growth factor (GF) delivery properties and the in situ optimization of the use of the GF in the fixation of bone screws through a dental implant. To describe the drilling process, an explicit dynamic numerical model was created, where the results show a significant impact of the drilling process on the bone material. The simulation demonstrates that the space occupied by the screw causes stress and deformation in the bone during the perforation and removal of the particulate bone, resulting in the accumulation of material removed within the implant screw, filling the limit hole of the drill grooves present on the new BKS.

Ibandronate Suppresses Changes in Apatite Orientation and Young's Modulus Caused by Estrogen Deficiency in Rat Vertebrae

Bone material quality is important for evaluating the mechanical integrity of diseased and/or medically treated bones. However, compared to the knowledge accumulated regarding changes in bone mass, our understanding of the quality of bone material is lacking. In this study, we clarified the changes in bone material quality mainly characterized by the preferential orientation of the apatite c-axis associated with estrogen deficiency-induced osteoporosis, and their prevention using ibandronate (IBN), a nitrogen-containing bisphosphonate. IBN effectively prevented bone loss and degradation of whole bone strength in a dose-dependent manner. The estrogen-deficient condition abnormally increased the degree of apatite orientation along the craniocaudal axis in which principal stress is applied; IBN at higher doses played a role in maintaining the normal orientation of apatite but not at lower doses. The bone size-independent Young's modulus along the craniocaudal axis of the anterior cortical shell of the vertebra showed a significant and positive correlation with apatite orientation; therefore, the craniocaudal Young’s modulus abnormally increased under estrogen-deficient conditions, despite a significant decrease in volumetric bone mineral density. However, the abnormal increase in craniocaudal Young's modulus did not compensate for the degradation of whole bone mechanical properties due to the bone loss. In conclusion, it was clarified that changes in the material quality, which are hidden in bone mass evaluation, occur with estrogen deficiency-induced osteoporosis and IBN treatment. Here, IBN was shown to be a beneficial drug that suppresses abnormal changes in bone mechanical integrity caused by estrogen deficiency at both the whole bone and material levels.

Conducting Studies of the Am-241 Radionuclide Incorporated into the Human Body Using a Wound Detector

Purpose: to develop a method for experimental study of the distribution of radionuclide 241Am in human organs and tissues during wound admission to clarify the process of formation of doses of alpha radiation. Material and methods: in clinical practice of Burnazyan FMBC of the FMBA of Russia To improve the method of determination, an experiment was performed to determine the depth of radionuclide on pigskin with the location of 241Am point sources behind different thicknesses. Results: the used methods of measurement, tested on pigskin, allowed to obtain the dependence of the localization depth of radionuclide 241Am on the measured on the surface of the tissue ratios of photons with different energies. Conclusion: Set the ratio of photons with different energies on the thickness of the barrier (depth), and proven methodology allow you to go directly to the planning of experimental studies on the barrier effect created in the bone material, and including a radionuclide, the formation of doses of alpha radiation on the bone marrow.

Three-Dimensional Finite Element Investigation into Effects of Implant Thread Design and Loading Rate on Stress Distribution in Dental Implants and Anisotropic Bone

Variations in the implant thread shape and occlusal load behavior may result in significant changes in the biological and mechanical properties of dental implants and surrounding bone tissue. Most previous studies consider a single implant thread design, an isotropic bone structure, and a static occlusal load. However, the effects of different thread designs, bone material properties, and loading conditions are important concerns in clinical practice. Accordingly, the present study performs Finite Element Analysis (FEA) simulations to investigate the static, quasi-static and dynamic response of the implant and implanted bone material under various thread designs and occlusal loading directions (buccal-lingual, mesiodistal and apical). The simulations focus specifically on the von Mises stress, displacement, shear stress, compressive stress, and tensile stress within the implant and the surrounding bone. The results show that the thread design and occlusal loading rate have a significant effect on the stress distribution and deformation of the implant and bone structure during clinical applications. Overall, the results provide a useful insight into the design of enhanced dental implants for an improved load transfer efficiency and success rate.

Valorisation of Fish Bones: Effects of Preservation by Formic Acid on AL-extractable calcium, Phosphorus, Magnesium, and Potassium

Fishbones contain significant amounts of plant nutrients. Fish residues may be preserved by acidification to pH < 4, which may affect the extractability and plant availability of nutrients when applied as fertilisers. Grinded bone material from cod ( Gadus morhua ) heads was mixed with formic acid to investigate if acidification would increase the concentrations of ammonium acetate-lactate (AL)-extractable nutrients. Two degrees of fineness of fishbones (coarse 2-4 mm; fine < 0.71 mm) were compared at pH 3.0 and 4.0 plus a water control in a laboratory study over 55 days. Samples for extraction of AL-soluble P, Ca, Mg and K were taken on day 2, 15, 34 and 55. Whereas acidification clearly increased the concentrations of AL-extractable calcium (Ca-AL) and magnesium (Mg-AL), extractable phosphorus (P-AL) was only significantly increased in finely grinded bones at pH 3. After 34 days, 6% of the total content of P was extracted by AL in fine fishbones at pH 3. Without acidification about 1% of the P was extracted, possibly from phospholipids. This P-AL concentration was well above P-AL extracted from acidified coarse fishbones and from fine fishbones acidified to pH 4. With acidification, about 30% of total Ca and 10% of total Mg were extracted by AL, and the Ca-AL and Mg-AL concentrations were closely correlated. The reason for lower P-AL in coarse fishbones at pH 3 and 4, and fine fishbones at pH 4 than in water controls may be a precipitation of apatite from phospholipids and dissolved calcium.

ANTROPOLOGIA GROBÓW CIAŁOPALNYCH CMENTARZYSKA DZIEKANOWICE 22

The article presents the analyses and descriptions of two graves in the Dziekanowice grave field, site 22 (dated back to the late 10th – the late 13th centuries) located on the eastern coast of lake Lednica, approx. 90 m from the eastern bridge leading to Ostrów Lednicki. The isle hosts a hillfort regarded a seat of the then ruler, the sedes regni principales. Within the gord, in the second half of the 10th century, a complex of residential and sacral buildings was raised: a baptistery, a palas and a church. The burial rite as of the late 10th and the early 11th centuries, which appeared in what is now Poland’s territory, is typically associated with Christianity encroaching the area. The issues under discussion, which are not fully explained, include both the ways in which the dead were buried before skeletal burials were introduced and popularised, the methods used to promote the changes, acceptance thereof, the rate and the prevalence of the new mode of burying the dead. In the course of extended excavations in the Dziekanowice 22 grave field, 1,665 graves have been discovered with preserved bone material, among them two graves where cremated bodies were laid (cremation burial). The graves have been dated back to the early Middle Ages (the time of the grave field’s operation).

Surface Modification of Carbon Fiber-Polyetheretherketone Composite to Impart Bioactivity by Using Apatite Nuclei

The authors aimed to impart the apatite-forming ability to 50 wt% carbon fiber-polyetheretherketone composite (50C-PEEK), which has more suitable mechanical properties as artificial bone materials than pure PEEK. First, the 50C-PEEK was treated with sulfuric acid in a short time to form pores on the surface. Second, the surface of the 50C-PEEK was treated with oxygen plasma to improve the hydrophilicity. Finally, fine particles of calcium phosphate, which the authors refer to as “apatite nuclei”, were precipitated on the surface of the 50C-PEEK by soaking in an aqueous solution containing multiple inorganic ions such as phosphate and calcium (modified-SBF) at pH 8.20, 25 °C. The 50C-PEEK without the modified-SBF treatment did not show the formation of apatitic phase even after immersion in simulated body fluid (SBF) for 7 days. The 50C-PEEK treated with the modified-SBF showed the formation of apatitic phase on the entire surface within 1 day in the SBF. The apatite nuclei-precipitated 50C-PEEK will be expected as a new artificial bone material with high bioactivity that is obtained without complicated fabrication processes.