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ePaper created 2015-09-15, 12:06:46 | version 1.38.0
sult in the absence of a flap design. Minimising the surgical flap can have advantages for soft-tissue healing and patient comfort.6 However, it has been shown that flapless free-hand surgery, regardless of surgical experience, leads to malpositioning of implants and consequently to bone perforations and dehisences.7 This finding suggests that when using free-hand flapless surgery additional guid- ance during preparation of the implant bed and during implant placement is required. For this rea- son, navigation surgery can become an important tool in dental implantology, as it benefits from the advantages of using stereolithographic guided surgeryandovercomessomeimportantdrawbacks of stereolithographic-involved procedures. _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 subse- quently the CBCT images were converted into DICOM files and transformed into a 3-D virtual modelusingtheNavidentsoftwaresystem.Thecli- nicianwhoplacedthevirtualimplantsinthevirtual case report 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 35implants3_2015 Fig. 3a Fig. 3b Fig. 4a Fig. 4b