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Functionally graded biomaterials (FGBMs) have received significant attention in the recent years as potential candidates for the next generation of dental implant improvement. This happened due to their unique advantages and their ability to satisfy the requirements of both biomechanical and biocompatibility properties simultaneously. This study was aimed to analyze the effects of two radial and axial FGBM dental implants on the stress distribution near the dental implant-bone interface under a static load using finite element method (FEM). The model was restrained on a base supporting bone and vertically loaded with a force of 100 N on the top of the abutment. In the FGBM models, the implants are made of a combination of bioceramic and biometal composition, with properties that change gradually and continuously in the radial and axial directions. The numerical results indicated that the use of both radial and axial FGBM dental implants reduced the maximum von Mises stress in the cortical and the cancellous bones in comparison with the common titanium one, which leads to faster bone regeneration and early stabilization of dental implant system. The findings of the present study may have implications not only for understanding the stresses and deformations around the implant-bone interface but also for improving the performance as well as application of FGBMs in dental implant materials.

This work was performed to investigate the mechanical and tribological properties of polymethyl methacrylate (PMMA)-based bone cement strengthened by nano-alumina (Al2O3) and nano-hydroxyapatite (HA) particles. Seven cement groups with different amounts of Al2O3 (3 and 5 wt. %) and HA (5 and 10 wt. %) nano-particles were prepared and the nanoindentation and nanoscratch tests were employed to obtain the results. Substantial improvement/reduction in mechanical properties was observed for the addition of 3 wt. % of Al2O3 /5 wt. % of Al2O3 plus 10 wt. % of HA into the PMMA matrix. The additives had almost no obvious effects on the friction of PMMA (~0.3). This research revealed that only the specific weight percent of Al2O3 (here 3 wt. %), compared to other PMMA/Al2O3 and PMMA/HA/Al2O3 cement nanocomposites, had great potential as an added component in PMMA bone cement to provide a significant increase in the mechanical properties of the cement. [ABSTRACT FROM AUTHOR]