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ePaper created 2015-06-05, 15:15:11 | version 1.38.0
I case report 16 I implants2_2015 Figs. 4–7_Insertion of two implants with a modern design and a porous tantalum cylinder, as well as promising osseo-incorporation. Fig. 4 Fig. 6Fig. 5 onlybeavoidedbymeansofadetailedqualitycontrol system. Apart from the problems already mentioned, further issues to consider include implant body de- sign, compatibility between thread designs and im- plantsurfacetreatment,implantcleaningprocedure, aswellasmacro-andmicro-roughness. While many of the production defects lead to im- plant fracture, surface problems remain initially un- detected. Implant surface problems can be observed at re-entry when, for example, the removal of the cover screw leads to implant removal or rotation. Such implants become mobile and fail; if not at this stage, this failure will be seen after several weeks of implantloadingatthelatest. _Case description Inthiscase,theclinicalsituationwassimilartothat describedabove.Thepatientreceivedfourimplantsin the maxillae in regions #15, 16, 24 and 26. Implant placementwasdelayedforallfourimplantsandbone augmentationwithamaxillarysinusliftlimitedinex- tent was performed at #16 and 26. The re-entry was performed five months postoperatively and pros- thetictreatmenttwoweekslater. Two weeks after loading, the patient complained aboutocclusalmalfunctioninregion#16.Theclinical examination found a mesial rotation of #16 of ap- proximately10degrees.Acloserlookrevealedimplant mobility.Ontheradiograph,wecoulddetectbonere- sorption around implant #16 (4.7 mm × 8 mm) of 2 mm distally and around implant #15 (4.1 mm × 8mm)of1mmmesially.Nonetheless,theseobserva- tions were insufficient to explain the clinical findings (Figs.1–3). _Healing period without complications Themobilityof#16wasidentifiedasrotation.Sep- arating the crowns from each other and the adjacent tooth, #14, led to explantation at zero torque. The macroscopic examination of the implants found a cleanimplantsurfaceonthecoronalhalfandsomein- dications of tissue on-growth on the apical half. The osteotomyintheboneshowednosignsofsoft-tissue ingrowth,asisoftenseenincasesofimplantmobility caused by peri-implantitis. Further signs of inflam- mationwerenotevident. Since we could not explain the reason for this im- plant failure, we decided against immediate implan- tation and to allow healing of the sockets. After a collagen fleece had been applied to the sockets, the woundwasfixedwithsinglesutures. Implant#15wassentbacktothemanufacturerfor reclamation and analysis. Implant #16 was sent to a university for further examination, microscopy and reflectionelectronmicroscopemorphometry.Ourfo- cuswasontheanalysisofdefectsanddetermination oftheimplantsurfaceroughnessinordertocompare thisanalysiswiththemanufacturer’sdata. Three months after the implant failure, the surgi- cal was repeated. Since we had not received a state- mentfromthemanufactureryet,wedecidedonadif- ferent implant type. We inserted two implants with a moderndesignandaporoustantalumcylinder,aswell aspromisingosseo-incorporation(Figs.4–7).Inorder to reduce risk and prevent any further complications, we allowed a healing phase of four months, taking into consideration that the rest of the implant body hadshownstandardsurfacecharacteristics. During surgery, we determined after raising the flapthatnobonelossresultingfromtheexplantation hadoccurred.Alsoalloftheboneaugmentedbuccally during the first surgery (region #15) remained. These findings solidified our strong suspicion that the first implant probably had surface defects that had influ- encedosseointegration.Guidedboneregenerationat region #16 to ensure 2 mm of bone buccally (sand- wich technique with autologous bone, allograft and xenograft;Figs.8&9)wasperformed.Theimplantsin- sertedhadadiameterof4.1mmand4.7mm,respec- tively. The implants’ healing occurred without any com- plications. After implant loading, we performed an- other radiograph to observe peri-implant tissue and