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ePaper created 2018-01-31, 10:01:59 | version 1.38.0
cone beam supplement | Fig. 17 Fig. 18 Fig. 19 Figs. 17 & 18: Optimal surgical result. Fig. 19: Exact angular position of posterior implants for angulated abutments. Osteotomy planning When the CT scan is imported into Navident, a propri- etary algorithm detects the fiducial’s image in the scan, then registers it with a mathematical model of the fiducial that is stored in the computer memory. This enables Nav- ident to map the Jaw Tag, which is the tag mounted onto the patient, to the CT image during navigation. For this case, Ankylos dental implants had been se- lected. The implants with a diameter of 3.5 mm and a length of 11 mm were planned on the locations 15, 12, 22 and 25 using the Navident planning software (Fig. 11). The following parameters were considered when osteo- tomies were planned: 1. Alveolar ridges, though they had a sufficient bone height, were narrowing at the crestal 1/3. Without waiv- ing or compromising the restorative infor mation, the implant locations were planned to be deeper where at least 2 mm of buccal plate thickness could be achieved. 2. Straight implants were placed at 12 and 22 and tilted ones at 15 and 25. 3. Angulated distal implants were planned 1 mm mesially to the sinus wall. 4. The angle of distal abutments was planned to be 30 de- grees to the occlusal plane to have the retaining screws access holes placed in the denture’s occlusal aspect since screw-retained abutments have 30 degree joints. 5. The plane of the implant collars was planned to be parallel to the occlusal plane. Surgery Before surgery, the CT marker was disconnected from the NaviStent Arm and replaced by the Jaw Tag, which is detected by the Navident camera. A Drill Tag was in- stalled onto the handpiece (Fig. 12). Together with the Jaw Tag, they provide real-time feedback during surgery, enable the surgeon to communicate with the software and place the implant as planned. A crestal incision was made at either side. Pilot drills were used to start osteotomy followed by the Ankylos den- tal implant drilling protocol. All drills were navigated ac- cording to the planned trajectory, until real- time feedback confirmed that its tip has reached the apical end of the planned osteotomy. The alveolar crests were levelled by a rongeur (Fig. 13). Between each trimming attempt, the pi- lot drill was touched to the trimmed surface of the crestal bone and its level was checked on the virtual image. The trimming of the bone was completed under the guid- ance of dynamic navigation and the pilot drill was again touched to the newly formed alveolar crest. Implants were inserted in the osteotomies as planned (Figs. 14–16), the gin- gival tissue placed back and sutured with coated poly-glactin 910 sutures. The patient was medicated with antibiotics and chlor hexidine mouth rinse and was released with NSAID’s. Conclusion The Navident navigation surgery system achieves a successful guidance both in alveoloplasty and implant osteotomies in the edentulous maxilla (Figs. 17–19). In the presented case, the proposed protocol was highly efficient in gathering 3-D prosthetic and anatomical in- formation for the planning. Dynamic navigation provided a precise guidance in the execution of the planned oste- otomies through a flexible surgical operation. Editorial note: A list of references is available from the publisher. contact Prof. Dr Hakan Uysal DDS, PhD, Prosthodontist Abdi Ipekçi Cad. 61 Tesvikiye Istanbul, Turkey Tel.: +90 212 2196744 uysalh@gmail.com Dr Noyan Bas¸ al Klinik212 dental clinic Valikonag˘ i Cad. No:86/A Nis¸ antas¸ i Istanbul, Turkey Tel.: +90 5324139118 noyanbasal@gmail.com CAD/CAM 1 2018 43