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ePaper created 2015-11-12, 17:51:56 | version 1.38.0
has been shown that flapless free-hand surgery, regardless of surgical experience, leads to mal- positioning of implants and consequently to bone perforationsanddehisences.7 Thisfindingsuggests that when using free-hand flapless surgery addi- tional guidance during preparation of the implant bed and during implant placement is required. For this reason, navigation surgery can become an im- portant tool in dental implantology, as it benefits from the advantages of using stereolithographic guided surgery and overcomes some important drawbacks of stereolithographic-involved proce- dures. _Case presentation The patient treated was a 21-year-old female consulting the dental office for replacement of both second premolars in the maxilla, at regions #15and25.Thepatientwasingoodgeneralcondi- tionandanon-smoker.Shehadbeentreatedbefore at the orthodontic department at Ghent University Hospitalbecauseofmultipledentalagenesis.Intra- oral examination revealed the absence of both lat- eral incisors and second premolars in the maxilla and both second premolars in the mandible. Peri- odontal screening showed no signs of pathology. The bone anchors used during the orthodontic treatment were still present in the second and fourthquadrants.Treatmentinvolvedplacementof two dental implants in the edentulous regions of the maxilla. Both implants were to be restored with two provisional crowns within 12 hours of implant placement (immediate loading). Preoperatively, an impression of the dental arch wastakenusinganirreversiblehydrocolloid(Cavex CA37, fast set, Cavex Holland) to fabricate a diag- nostic cast. This cast was used as a model for the moulding of the surgical stent; hereafter called NaviStent (Figs. 1a & b). The NaviStent served as a scanning template and was also worn by the pa- tient during the surgery. Afterwards, the patient wassentforaCBCTscanwiththeNaviStentinplace (Figs. 2, 3a & b, 4a & b). _Planning procedure A standard CBCT scan was performed according totheprocedureoutlinedintheNavidentscanning protocol from ClaroNav. Cone beam images were taken with a Planmeca ProMax 3D Max (Planmeca) with a flat-panel detector and isotropic voxels. The fieldofviewusedforthiscasewas50mm×100mm and a voxel size of 200 μm. The exposition parame- ters were 96 kV and 10 mA. Care was taken to align the field of view with the jaw and the radiographic tracker, which was situated anterior of the jaw. All images were carefully reviewed and sub- sequently the CBCT images were converted into DICOM files and transformed into a 3-D virtual modelusingtheNavidentsoftwaresystem.Thecli- nicianwhoplacedthevirtualimplantsinthevirtual case report _ guided implant surgery I Figs. 3a & b_Pre-op image of region #15 and a lateral photograph. Figs. 4a & b_Pre-op image of region #25 and a lateral photograph. I 15CAD/CAM 4_2015 Fig. 3a Fig. 3b Fig. 4a Fig. 4b CAD0415_14-17_Dhaese 06.11.15 11:58 Seite 2 CAD0415_14-17_Dhaese 06.11.1511:58 Seite 2