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Animal experiment: Surface wear analysis1515of the fossa component. Also, sheep #5158 showed a normal positioning of the TMJR at three months after surgery, yet a limited latero-inferior displacement of the fossa was found during the post-operative dissection. A similar displacement was found in sheep #2177 at both the 6-month post-operative CT scan that was made as an exception, for a study analyzing the LPM insertion to the TMJR, as well as during explantation. However, as the displacement of the fossa was rather limited, this only led to a slightly more laterally positioned wear volume in case of ewe #5158 and the edges of the wear volume were less sharply marked in case of sheep #2177 (Fig. 6). In addition to these three displaced fossa, also the fossa of ewe #4246 showed a deviant wear pattern, with a slight lateromedial extension of the wear track. This could potentially be caused due to laterotrusive movements of the contralateral joint, with the implanted side functioning as stabilizing joint.Table 3: Amount of volumetric ultra-high molecular weight polyethylene wearSample Total volumetric wear (mm3)Volumetric wear/year (mm3/y) (Sheep) Volumetric wear/year (mm3/y) (Human)H-DLC-coated TMJR 4249 42.70 mm³ 54.12 mm³ / y 1.94 mm³ / y2177 16.45 mm³ 20.85 mm³ / y 0.75 mm³ / y3520 31.79 mm³ 40.29 mm³ / y 1.45 mm³ / y 2549 32.92 mm³ 41.7 mm³ / y 1.5 mm³ / y5185 9.18 mm³ 11.63 mm³ / y 0.42 mm³ / y8087 18.68 mm³ 23.67 mm³ / y 0.85 mm³ / yNon-coated TMJR 1724 32.61 mm³ 41.33 mm³ / y 1.48 mm³ / y4246 27.77 mm³ 35.19 mm³ / y 1.26 mm³ / y8787 59.45 mm³ 75.34 mm³ / y 2.7 mm³ / y0032 26.47mm³ 33.84 mm³ / y 1.20 mm³ / y4248 82.96 mm³ 105.15 mm³ / y 3.77 mm³ / y7998 - - -4473 - - -For both sample 7998 and 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. Abbreviation: TMJR: Temporomandibular joint replacementThe displacement of these three fossa was most likely due to the use of 2mm diameter screws for the fixation of the fossa component, as is done Nikolas de Meurechy NW.indd 151 05-06-2024 10:14