implants - international magazine of oral implantology

industry report I nisms (e.g. CeHa implant [X1;X2]™, coDiagnostiX [gonyX ]™ etc.) may also be a considerable source of error for the transfer process. Intraoperative errors mayalsooccur:anincorrectlyplacedsurgicalnaviga- tion template will certainly lead—in case of specific navigated implant placement—to malpositioning of the implants, thus possibly resulting in inadvertent, unplanned injury to the adjacent structures. Malpo- sitioning of implants may also occur if the “half- guide” (only the pilot drilling is navigated) procedure is employed. As far as this is concerned, “full-guide” procedures appear safer but may be limited in their applicability.Thisexcerptoferrorsisapossibleexpla- nation for the relatively high inaccuracy of proce- duresusedtodateasdocumentedintheabove-men- tioned DGZMK guidelines. _Further development The CTV system follows different paths, based on comprehensive theoretical and clinical evaluation, in ordertoattaininterdisciplinarycooperationandreli- able planning with only minimal toleration of errors. Use of the CTV system allows coincidental and there- fore unforeseeable errors to be identified and, wher- ever feasible, systematic errors to be compensated for. The quasi-analogue image processor developed fortheCTVsystemisrelativelytolerantwherequality and alignment of the primary radiographic dataset are concerned. It permits any image sections in 3-D cubestobecreatedwithnolimitationstoangles,dis- tances and locations. These images reproduce im- pressive details and structures as do plain images, calculated panoramic tomographs and calculated teleradiographs. The operator is provided with the usual “analogue” image quality. But the same applies here, too: The quality of the primarydatasetandthedensityoftheinformationit contains is decisive for the 3-D diagnostic and plan- ningoptions.Inaddition,theCTVsystemmergesdata fromanopticalscanoftheplanningtemplate,model and/or wax-up/aesthetic set-up and/or drilling tem- plate with the 3-D radiographic planning dataset (Figs. 3-5). This fully automatic matching process discoversandcompensatesforcoincidentalerrorsin images (Figs. 6 & 7). Regarding bone availability and prosthesis posi- tioning, the planning positions can thus be deter- mined more comprehensibly and exactly. When us- ing this method, the emergence profile can already beestimatedaccuratelyduringprosthetic(pre)plan- ning. The surgical navigation template can also be fabricatedbasedonSTLdatasets.Whenthistemplate is then matched with image planning, the (virtual) planning positions can be checked for correct align- ment with the sleeve positions in the template prior to placement. Starting with optical and radiological digital data, the entire planning and fabrication processisdigitizedfromonesinglebasewithoutfur- ther interim stages, which eliminates inaccuracies Figs. 6a–b & 7a–d_An example of error recognition – checking and determining the gingival contours on the planning radiographs using the scan of the model. Figs. 8a–d_The gingiva or tooth structures are recognised automatically when the radiological planning data are matched to the model of the jaw or wax-up. I 39implants3_2013 Fig. 6a Fig. 6b Fig. 7a Fig. 8a Fig. 8b Fig. 8c Fig. 8d Fig. 7b Fig. 7c Fig. 7d Gingiva line after matching with model. Tooth line after matching with wax up. Determined height of gin- giva in X-ray planning (pink). Out of implant planning resulting position of the drill. Yellow line: real line of gingiva on basis of scanned model—sleeve below gin- giva! Source of error: arte- facts in CT-scan due to precious metal containing restoration (z-level-cut). Yellow line: automatically reconstructed line of gingiva on basis of model scan.