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ePaper created 2017-12-06, 11:14:19 | version 1.38.0
industry | Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 The precise location of implants is case-specific and determined by different factors. If an edentulous case is to be restored with an implant-supported screw-retained fixed prosthesis, implant locations should be critically examined whether they can pro- vide screw access holes within occlusal or palatal/ lingual parts of the restoration. Frequently, alveolo- plasty is required for the recontouring of the ridge in order to obtain sufficient bone thickness at the level of the implant’s collar. This crestal trimming of bone may also be neces- sary in order to increase the inter-arch space and pro- vide a sufficient volume for the restorative material, since dentogingival prostheses are frequently re- quired to enhance aesthetics. In such cases, dynamic guidance can be used to level the alveolar crests as planned on virtual images, followed by precise multiple osteotomies. Case The following case report describes the treatment of a 65-year-old male with an one-year history of maxillary partial edentulism (Fig. 1). He was discon- tent with the stability of his prosthesis and expressed that through the unstable prosthesis situation he has lost social self-confidence. In the initial appointment he thus stresses his need for a “fixed solution”. His medical history did not reveal any specific sys- temic disease or condition that contraindicates oral surgery. The patient’s soft tissues on the edentulous ridges were healthy and panoramic X-rays showed expanded sinuses at both sides and irregular alveolar ridges. The treatment plan, carried out for a maxillary screw-retained fixed prosthesis, included two im- plants at the pre-maxillary region and two tilted in the posterior maxilla to avoid a sinus lift surgery. Stent placement In order to acquire both anatomical and prosthetic information prior to the surgery, a scan prosthesis was manufactured by duplicating the maxillary den- ture (Fig. 2). It is important that the scan prosthesis has the same aesthetic and functional information as the complete denture or set-up. Thus, the scan pros- thesis was checked for its fit, aesthetics and maxilla mandibular relation (Fig. 3). The scan prosthesis was then used together with a Navident Edentulous Kit for CBCT imaging. The Navident edentulous protocol consists of a SDI (Small Diameter Implant of 2.2 mm or 2.5 mm diame- ter), which is inserted into the alveolar ridge of the arch to be operated, prior to the acquisition of the CT scan. This temporary SDI serves as a mount for the CT marker and for the Jaw Tag used for the registration of the CT scan to the patient and for tracking the patient’s jaw during surgery. The SDI can be placed either in a vertical position or in a horizontal position in relation to the alveolar crest. A special plastic arm with a proprietary alumin- ium bracket is then used for the connection of the CT marker and Jaw Tag to the SDI. Two types of arms are available: one for a vertically placed and another for a horizontally placed SDI (Figs. 4a & b). In the presented Fig. 5: Placement of an SDI as anchor mount. Fig. 6: Connecting the NaviStent Arm to the SDI. Figs. 7 & 8: Adjusted scan prosthesis for combined scanning. Fig. 9: Connecting the CT marker to the NaviStent. Fig. 10: Patient positioning in the CBCT scanner. implants 3 2017 39