Biomechanická studie lebečních implantátů s různými tloušťkami a materiálovými vlastnostmi

Biomechanical performance of cranial implants with different thicknesses and material properties: A finite element study

journal article in Web of Science

en

This study investigated the effect of implant thickness and material on deformation and stress distribution within different components of cranial implant assemblies. Using the finite element method, two cranial implants, differing in size and shape, and thicknesses (1, 2, 3 and 4 mm, respectively), were simulated under three loading scenarios. The implant assembly model included the detailed geometries of the mini-plates and micro-screws and was simulated using a sub-modeling approach. Statistical assessments based on the Design of Experiment methodology and on multiple regression analysis revealed that peak stresses in the components are influenced primarily by implant thickness, while the effect of implant material is secondary. On the contrary, the implant deflection is influenced predominantly by implant material followed by implant thickness. The highest values of deformation under a 50N load were observed in the thinnest (1 mm) polymethyl methacrylate implant (Small defect: 0.296 mm; Large defect: 0.390 mm). The thinnest Polymethyl methacrylate and Polyether Ether Ketone implants also generated stresses in the implants that can potentially breach the materials' yield limit. In terms of stress distribution, the change of implant thickness had a more significant impact on the implant performance than the change of Young's modulus of the implant material. The results indicated that the stresses are concentrated in the locations of fixation; therefore, the detailed models of mini-plates and micro-screws implemented in the finite element simulation provided a better insight into the mechanical performance of the implant-skull system.

Tato studie zkoumala vliv tloušťky implantátu a materiálu na deformaci a rozložení napětí v soustavě kraniální implantát – lebka. Pomocí metody konečných prvků byly řešeny dva kraniální implantáty, lišící se velikostí a tvarem a tloušťkami (1, 2, 3 a 4 mm), ve třech scénářích zatížení. Výpočtový model implantátu zahrnoval detailní geometrie mini-desek a mikrošroubů a byl simulován pomocí sub-modelovacího přístupu. Statistické hodnocení založené na metodice Design of Experiment a na vícenásobné regresní analýze ukázalo, že špičková napětí ve složkách jsou ovlivněna především tloušťkou implantátu, zatímco účinek materiálu implantátu je sekundární. Naproti tomu průhyb implantátu je ovlivněn převážně implantačním materiálem a následnou tloušťkou implantátu. Nejvyšší hodnoty deformace při zatížení 50N byly pozorovány v nejtenčím (1 mm) polymetylmetakrylátovém implantátu (malá vada: 0,296 mm; velká vada: 0,390 mm). Pokud jde o rozložení napětí, změna tloušťky implantátu měla výraznější vliv na výkon implantátu než změna Youngova modulu implantačního materiálu. Výsledky ukázaly, že napětí jsou soustředěna v místech fixace; proto podrobné modely mini-desek a mikrošroubů implementovaných v simulaci konečných prvků poskytly lepší pohled na mechanické vlastnosti soustavy implantát-lebka.

This study investigated the effect of implant thickness and material on deformation and stress distribution within different components of cranial implant assemblies. Using the finite element method, two cranial implants, differing in size and shape, and thicknesses (1, 2, 3 and 4 mm, respectively), were simulated under three loading scenarios. The implant assembly model included the detailed geometries of the mini-plates and micro-screws and was simulated using a sub-modeling approach. Statistical assessments based on the Design of Experiment methodology and on multiple regression analysis revealed that peak stresses in the components are influenced primarily by implant thickness, while the effect of implant material is secondary. On the contrary, the implant deflection is influenced predominantly by implant material followed by implant thickness. The highest values of deformation under a 50N load were observed in the thinnest (1 mm) polymethyl methacrylate implant (Small defect: 0.296 mm; Large defect: 0.390 mm). The thinnest Polymethyl methacrylate and Polyether Ether Ketone implants also generated stresses in the implants that can potentially breach the materials' yield limit. In terms of stress distribution, the change of implant thickness had a more significant impact on the implant performance than the change of Young's modulus of the implant material. The results indicated that the stresses are concentrated in the locations of fixation; therefore, the detailed models of mini-plates and micro-screws implemented in the finite element simulation provided a better insight into the mechanical performance of the implant-skull system.

Cranioplastika; Lebeční implantát; 3D tisk; MKP; Mechanické vlastnosti

Cranioplasty; Skull implant; 3D printing; Finite element method; Mechanical properties

03.06.2019

0010-4825

109

43–52

10