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ePaper created 2016-09-14, 10:12:26 | version 1.38.0
The titanium grade 4 implant CO-XG (PHOENIX) had a rough implant body and a machined implant neck. In contrast to all otherone-pieceimplantsinthecohort,the CO-CG showed large burrs on some outer threads that may lose the remaining con- tact with the implant during insertion (Fig. 11). Whereas the implant body was mainlyfreeofresidues(Figs.12and16),the machinedareaoftheimplantneckrevealed a massive organic contamination with large particles (100–300 µm) containing not only carbon, but also significant traces of magnesium, aluminium and antimony (Figs. 13–15, Tabs. 4 and 5). TheimplantAllfitKOSpresentedaninho- mogeneousdistributionpatternofremain- ing aluminium oxide particles on the rough implant body as remnants of the blasting material with different sizes from 5 to 50 µm (Figs. 17–18). The machined threads at the implants neck that are exposed to the cortical bone showed organic material in the narrow grooves (Figs. 19–20). The correspondent EDX analysis revealed a significant amount of carbon inside these gaps(Fig.21,Tab.6)andshowedthetypical signals of titanium grade 5 in the neigh- bourhood of these contaminants (Fig. 22, Tab. 7). Discussion There is an ongoing discussion, as to whether organic residues or major amounts ofblastingmaterialhaveaclinicalimpacton theprocessofosseointegration.11,12 Eventhe manufacturers of implants on whose im- plantsmoreorlesslargeamountsoforganic or inorganic contaminants were found in our analyses have reported statistical suc- cess rates that are not different from those of other implants, proving their point with specially conducted studies. Buthowdoesthehumanbodyhandleor- ganic particles or minor particles with traces of iron, chromium, nickel or even an- timony? This question should actually not arise in the first place, because impurities arepreventable,asthisstudyclearlyshows. Even if these particles are relatively firmly attached to the implant surface, they are likely to become detached by the resulting frictional forces in the bone bed as the im- plants are inserted at torques in the double digitstoachievethedesiredlevelofprimary stability. Particles with a diameter of less than 10 μm are susceptible to uptake by macrophages through phagocytosis,13 so that questions related to the clinical rele- vance of such impurities cannot simply be brushed aside. Ifwefollowtheshiftinparadigmandun- derstand that osseointegration is the con- sequence of a dynamic foreign body equi librium,ratherthanastaticsituation,every additional and avoidable foreign body on a sterilepackedimplantrendersactivationof the immune system and may be the reason for a periimplantitis.14,15 Especially in the early phase of osseointegration, a parti- cle-induced macrophage activation is as- sociated with an increased osteoclasto- genesis and may therefore cause increased bone resorption.16 According to Albrektsson, we should abide by his fundamental guiding principle that we have to know, not to believe, that a specific implant will do no harm to our pa- tients.17 To cut a long story short: Concern- C Atomic percentage Certainty 69.2 % 0.99 O 25.3 % 0.99 Ti Mg Al Sb 3.0 % 0.99 0.9 % 0.97 0.8 % 0.97 0.8 % 0.97 Tab. 4 Ti Atomic percentage Certainty 100.0 % 1.00 Tab. 5 Tab. 5: Quantitative elemental analysis of spot # 2 in Fig. 14. Tab. 4: Quantitative elemental analysis of spot # 1 in Fig. 14. AD