Please activate JavaScript!
Please install Adobe Flash Player, click here for download

CAD/CAM international magazine of digital dentistry

I case report _ patient-specific abutments Fig. 1_Maxillary anterior gap in regions 12, 11, 21 and 22 (Kennedy Class IV), four months after implant insertion. Fig. 2_Occlusal view of the maxilla with an interdental gap between teeth #13 and 23. Fig. 3_Implant exposure four months post-op. CAD/CAM patient-specific abutments and a new implant design Authors_Prof. Frank Liebaug & Dr Ning Wu, Germany 22 I CAD/CAM 4_2012 _Introduction The objective of any dental reconstruction is the natural, functional reconstruction of the stomatog- nathic system and the functionally unimpaired or functionally treated masticatory organ. This objec- tivecanonlybeachievedifindividualpatientparam- eters and distinctive anatomical features are incor- porated into surgical planning and the subsequent prosthetic restoration. Implant-prosthetic care methods must be estab- lished as independent therapy alternatives for spe- cialists and patients, and the possibility of achieving this objective is high. With attention focused on the prosthetic functional aspects of implantology, the pros- thetic therapy objective is currently becoming the focal point of all ef- forts. From the point of view of the practisingdentist,themainemphasis in treatment planning for implant- supported dentures is placed on the prosthetic specialist. If said specialist isalsotrainedinimplantsandsurgery, he will place the implant himself as a support measure for his prosthetic therapy, which results in great sim- plification with regard to planning and the treatment process. As a rule, however, a dentist who deals with prosthetics will complete his implant prosthesisinclosecollaborationwith an oral surgeon or oral-maxillofacial surgeon. While surgeons are concerned with the best possible implant pro- cedure or implant design, prosthetic specialists bring us back to the start- ing point of implantology: the pa- tient’s wishes. Patients do not want implants; rather they want beautiful newteethwithwhichtheyfeelconfi- dent in day-to-day life.1 Team-work is gaining increasing importance in thisregard,since,dependingonthefunctionalpros- theticobjective,prostheticspecialists,dentaltechni- cians and implant surgeons might have to work to- getherontheoptimalimplementationoftheplanned results using navigation and CAD/CAM systems. In the future, this method of integrating implantology willbefoundinjustabouteverypractice.Asthehard- ware for 3-D planning is currently very expensive, dentists should seek suitable partners to support them in the integration of current therapy options. Furthermore, from a biological and an economic perspective, production should rely on the most biologically compatible material with sufficient me- chanical stability, for example titanium and cobalt- chromium alloys. Zirconium oxide is also an option. However, in terms of casting engineering, the pro- cessing of these alternative materials does not offer sufficient precision of fit. Cast implant structures manufactured from non-precious metals have been foundtoexhibitgapswithanaveragewidthof200to 230 µm between the superstructure and the implant abutment.2 In contrast, cast structures manufac- tured from precious metal alloys have been found to have gaps with an average width of 40 to 50 µm.3 The use of alternative materials thus requires the use of alternative production technologies, if only to obtain the required precision. Ideally, a superstructure is milled from an indus- trially prefabricated solid material in order to elimi- nate inhomogeneities safely. Following this line of thought, milling-based manufacture of superstruc- tures using the CNC (computer numerical control) procedure began more than ten years ago. Attempts withthiskindofCAD/CAMtechnologydemonstrated that the achievable precision of current construc- tions—between 20 and 30 µm—is better than the precision of fit achieved with cast precious metal structures.3 With modern scanning and software technology, this production principle has been extended to the area of virtual construction. Thus, the CNC milling procedure, which has been used for years, is supple- mented with the possibility of a purely virtual con- Fig. 2 Fig. 3 Fig. 1