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Animal experiment: Surface wear analysis1495Table 2: Amount of linear ultra-high molecular weight polyethylene wearSample Max wear (mm)Maximal wear/year (mm/year) (Sheep) Maximal wear/year (mm/year) (Human)H-DLC-coated TMJR 3520 0.81 mm 1.03 mm / y 0.037 mm / y8087 0.51 mm 0.65 mm / y 0.023 mm / y2177 0.41 mm 0.52 mm / y 0.019 mm / y5158 0.34 mm 0.43 mm / y 0.014 mm / y2549 0.81 mm 1.03 mm / y 0.015 mm / y4249 1.15 mm 1.46 mm / y 0.052mm / yNon-coated TMJR 0032 0.64 mm 0.81 mm / y 0.029 mm / y7998 0.28 mm 0.35 mm / y 0.013 mm / y4246 0.72 mm 0.91 mm / y 0.033 mm / y1724 0.81 mm 1.03 mm / y 0.036 mm / y8787 1.35 mm 1.71 mm / y 0.061 mm / y4248 1.48 mm 1.88 mm / y 0.067 mm / y4473 >1 mm > 1.27 mm / y > 0.045 mm / yFor sample 4473, the error margin in the overlap between the two STL models was too large for the ‘best fit’ iterative closest-point algorithm to provide reliable results. Based on the 3D scanner analysis, the linear wear was found exceed one millimeter, yet no specific result was determined.Abbreviation: TMJR: Temporomandibular joint replacementDiscussionThe present study evaluated a novel model of TMJ TJR in a sheep model and set out to identify the wear patterns of both the condylar and fossa components of the prosthetic device implanted over a period of 288 days. This theoretically equals an estimated lifespan of 22 years in human implantation, based on the number of mastication movements.While being an in vivo experiment, we were not constricted to the use of in vivo wear evaluation techniques such as the radiostereometric analysis introduced by Selvik et al. (26) as the sheep were sacrificed and the TMJR were explanted. Thus optical scanning was used to determine linear UHMWPE wear, while CMM laser scanning was used to determine volumetric UHMWPE wear and reconfirm the results on linear wear. The articulating Ti condylar surface was analyzed as well, by means of scanning electron and confocal laser microscopy surface.Nikolas de Meurechy NW.indd 149 05-06-2024 10:14