CAD/CAM international magazine of digital dentistry No. 4, 2016

| case report full mouth restoration 16 CAD/CAM 4 2016 Addressing bone loss and implant angulation with custom abutments and monolithic zirconia Author: Dr Ara Nazarian, USA Introduction According to the Misch prosthetic classifications for completely edentulous patients, the FP3 (fixed-prosthesis-3) is an implant restoration that addresses cases with significant tissue loss by in- cluding pink gingival areas that replace the lost boneandsoft-tissuecontours.1 TheFP3prosthesis allows for the reestablishment of proper function, esthetics,lipsupportandphoneticswhileavoiding over-elongated teeth. The fixed nature of this prosthesis type affords the highest levels of sta- bility, chewing capability and patient satisfaction, making it the premium restorative option for fully edentulous cases.2 For clinicians who favor the maximum durability and high esthetics of monolithic zirconia, the ver- satilityofdentalCAD/CAMtechnologyallowsfora screw-orcement-retainedrestoration.Whileboth of these prosthetic options offer a predictable, highlyeffectivemeansofrestoringtheedentulous arch,thisarticlewillfocusontheindications,treat- ment protocol and benefits of the cementable full-arch BruxZir restoration (Glidewell Europe GmbH; Frankfurt/Main, Germany) over custom abutments. Because of bone loss and anatomical factors, some implants must be tilted buccal-lingually in a manner that would situate the access holes on the incisal edge or facial aspect of a screw-retained restoration. The use of custom abutments and a cementable prosthesis corrects the angulation of the implants and eliminates the need for screw access holes. This approach also allows for a pros- thesiswithlessbuccal-lingualwidthinthesechal- lenging situations. Using CAD software, custom abutments can be designed in the precise manner needed to support an esthetic restoration. And becausetheentirebodyoftherestorationismilled from high-strength monolithic zirconia, the prob- lems of wear, chipping and fracture that can occur with layered porcelain, which has traditionally been used in cementable full-arch bridges, are prevented. DeterminingwhetheracementableFP3prosthesis is indicated largely depends on the bone charac- teristics of the patient and the preferences of the practitioner. The clinical workflow for the full-arch BruxZir bridge over custom abutments is relativelysimpletofollowandincludesmanytech- niques used in traditional crown & bridge work. The protocol includes a poly(methyl methacrylate) try-in bridge, which offers a three-dimensional preview of the proposed restoration and is a pre- cise communication tool between the practitioner anddentallab.Anynecessaryalterationsaremade to the PMMA try-in bridge, digitally scanned by Fig. 1: Preoperative full-face view of the patient. Fig. 2: Initial condition of patient, including edentulous upper arch and severe caries of his mandibular dentition, which was untreatable and required extraction. Fig. 3: Panoramic radiograph exhibits adequate vertical bone height for implant treatment. Fig. 4: Tissue-level surgical guide in place. Fig. 1 Fig. 2 Fig. 3 Fig. 4 42016

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