CAD/CAM - international magazine of digital dentistry

I 23 case report _ dental implantology I CAD/CAM 2_2014 preserved and stabilized. This requirement was incor- poratedintotheplanning,andtheemergenceprofile of the implant from the soft tissue was considered already at this early stage. The final implant location was based on the existing anatomical parameters and the desired prosthetic restoration (Fig. 3a). _Initial surgical session According to the plan and the drilling protocol, the implant was inserted in region 36 and the bone grafted in the buccal area (Fig. 3b). To fabricate the abutment during the healing phase of the implant, it was necessary to transfer the situation (implant location) from the mouth to the cast model as precisely as possible. The index registration proved successful for this purpose. The implant impression copingwasscrewedintoplaceinthemouthandthe implantlocationfixedusingaplasticindexkey.After removing the central screw, the key was removed from the mouth with the impression coping and transferred to the dental laboratory with the im- pression for fabrication of the master cast. A cover screw was used to enable a submerged healing. _Fabrication of the abutment Thedentaltechnicianusedtheindexkeytotrans- fer the exact location of the implant to the cast and to mold a wax-up of the planned prosthetic restora- tion.Basedonthisspecification,theidealemergence profilewasdefined(basedonbiologicalwidth)(Fig.4). A gingival mask provided the corresponding emer- gence profile of the basal abutment area. It was im- portant to design the connection between the abut- ment and the later crown at gingival level to prevent excess cement from compromising the long-term result. A subgingival crown margin significantly increases the risk of overlooked excess cement.2 ATLANTIS (DENTSPLY Implants) was chosen to design and fabricate the abutment using CAD/CAM technology. This concept allows custom abutments for cement-retained prosthetic solutions to be cre- ated in a simple and efficient manner. After scanning theimplantcast(withgingivalmask),adetailedthree- dimensionalimageoftheintra-oralsituationemerged. At the Design & Fabrication Center (ATLANTIS), a vir- tual abutment was fabricated based on the patient’s specific situation and an image of the situation sent tothetreatmentteamviathewebportal(Figs.5a&b). After assessing the templates and slightly adapting the virtual wax-up in the 3-D editor, the design was released and fabrication of the abutment ordered (Fig. 5c). Zirconium oxide, titanium, and titanium- nitride-coated titanium (GoldHue) are available as materials for implementation. In this case, titanium was the material of choice for the abutment, for rea- sonsofstability.Thelaboratoryreceivedtheindustri- ally fabricated abutment just a few days after receiv- ing the ordering information. It fits perfectly on the cast model and required no rework. The instructions were to leave the basal area of the abutment un- touched and not polish the abutment in any way. The titanium surface has a certain roughness in the area of the emergence profile, which optimally sup- ports epithelial attachment of the soft tissue (Fig. 6). However, the abutment was not the only component to be fabricated in preparation for the next appoint- ment (Figs. 7a & b). The temporary crown also had to be cemented in the mouth at the appointment for placing the abutment. Therefore, the dental techni- cian fabricated a monolithic crown (CEREC, Sirona) madeoflithiumdisilicatebasedonthewax-up(Fig.7c). Fig. 10_The exposed implant is ready to receive the abutment. Figs. 11a & b_The transfer guide supported accurate positioning of the abutment in the mouth. Fig. 11b Fig. 11aFig. 10 CAD0214_20-24_Bergmann 13.05.14 11:16 Seite 4