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Nowadays, numerous internal bone remodelling concepts are under development, in order to estimate long-term functionality of implants by evaluating the intensity of stress-shielding effect. This effect is also analysed for the implants for direct skeletal attachment, considered as a better exoprosthesis fixation method than prosthetic sockets. Most of bone remodelling approaches are based on basic concepts, differing with certain assumptions, which may affect the accuracy of the results. This article compares commonly used internal bone remodelling concepts and evaluates the functionality of the proposed Limb Prosthesis Osseointegrated Fixation System for direct skeletal attachment of limb prosthesis in comparison with two currently available implants: the Intraosseous Transcutaneous Amputation Prosthesis and the Osseointegrated Prostheses for the Rehabilitation of Amputees. Three concepts were chosen: without and with lazy zone and with the use of quadratic formula which considers bone overloading. Therefore, three finite element models were created with identical femur implanted with each of analysed implants. The implants were loaded with loads that refer to two stages of gait cycle (heel strike and toe-off). The analysed concepts have given similar results, allowing to assume that each of them can be successfully used to estimate internal bone remodelling around analysed implants for direct skeletal attachment of limb prosthesis. The results also present higher functionality of the proposed implant for direct skeletal attachment of limb prosthesis due to a significant reduction in stress-shielding in the analysed areas around implant in comparison with the Intraosseous Transcutaneous Amputation Prosthesis and the Osseointegrated Prostheses for the Rehabilitation of Amputees. It suggests that the proposed design is a better alternative to the currently used solutions.

In this article, an energy approach based on the correlation between dissipated friction energy and wear volume was used to compare wear resistances of human tooth enamel and four composite dental materials: Arkon, Ecusit, Ful-Fil, and Filtek. The results of the study showed that the wear resistance of enamel is approximately one order or more higher than the one obtained for the dental materials. The effectiveness of the approach used has also been shown. Scanning electron microscopy (SEM) examinations and chemical analysis surfaces subjected to tribological experiments made it possible to uncover substantial differences in the wear mechanisms occurring on enamel and the dental material surfaces. The wear mechanism of the dental materials used in the study is characterized mainly by chemical changes, while enamel is mainly subjected to physical transformations.