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

CAD/CAM - international magazine of digital dentistry

industry report _ aesthetic dentures I I 29CAD/CAM 4_2013 such as IPS e.max Ceram (Ivoclar Vivadent), good aesthetics can be attained.9 The lithium disilicate ingots are specifically designed for press-on procedures indicated for zirconium oxide-supported gingiva portions, single-toothrestorations,anteriorandposterior bridges, inlay-retained bridges, and implant superstructures.10 Manufactured in nine block sizes, the larger ones suitable for long-span bridge frameworks or for stack milling and the smaller ones for cop- ings, zirconia substructures can satisfy patient’s demands for high-strength, highly aesthetic, functional, fixed prosthetic results.10 TheAll-on-4treatmentconcept(NobelBiocare) includes fixed and removable prosthesis and canbeusedincombinationwithafull-archzirco- nia substructure as well as a variety of implants (Nobel Active, Nobel Biocare). The ability to screw a provisional prosthesis onto the implants di- rectly after surgery provides edentulous patients with an immediate implant-supported restora- tion.11-15 Accommodating a wide range of abut- ments and prosthetics, this technique benefits patients by providing an aesthetically pleasing, comfortable,stableandfunctionalprosthesis.11-16 _Clinical Protocol The patient presented with severely worn and damaged dentition (Figs. 1 & 2). After perform- ing a panoramic X-ray of the patient’s mouth, it was decided that the complete removal of all remaining teeth was necessary (Fig. 3). The treatment agreed upon was the application of the All-in-4 technique (Nobel Biocare). Therefore, the first step was to guide the placement of the four RP Nobel Active implants, and the multi-unit transmucosal abutments used to facilitate tissue level emergence by cre- ating a precision surgical implant guide. Once the implants were placed, impression copings were inserted, an impression was taken from which to create the master cast and immediate dentures were placed (Fig. 4). A face-bow transfer was performed to ide- alise the parameters for a precision restoration (Fig. 5). At this point, the decision was made to fabricate a zirconia-hybrid prosthesis for the upper arch and an acrylic prosthesis for the lower (Fig. 6). A laboratory verification jig was created from the master cast to guarantee the accuracy of the final fit. To set tooth arrange- ment and function, an occlusal wax rim was created. The set-up was then screwed in, the bite verified, and phonetics, function, and aesthetics approved. _Laboratory Protocol The patient-approved immediate denture was duplicated and mid-line smile design and curve positions, i.e., Wilson spee, incorporated (Fig. 7). The plastic temporary abutment was placed over the multi-unit abutment (Fig. 8) and parts A and B of the resin were mixed and applied over the plastic abutment (Figs. 9 & 10), creatingtheresindenture(Fig.11).Theframewas designed and the scanning process performed (Fig. 12). The zirconia frame was tried in (Fig. 13). A variety of samples of IPS e.max Ceram were chosen from the shade guide to produce natural colouration and mask the white zirconia frame (Fig. 14). The colour was tested with the same background as the frame colour to evaluate the shade intensity of intensive dentin and dentin. The frame was characterised with Zirliner 1 and baked at 1,060 °C to create a bond between the zirconia and ceramic (Fig. 15). A full-contour wax crow design was com- pleted (Figs. 16 & 17). Intensive pink porcelain (IPSe.maxCeram)wasbuiltuptomasktheframe and mixed with opal enamel white (OE4) and opal violet in specific areas to create a natural look. The bake speed was lowered to 35 °C per minute, held for one minute at 760 °C, cooled at a rate of 25 °C per minute and held at 350 °C for 15 minutes (Fig. 18). Characterisation of the pink porcelain was finalised using Essence stains (Ivoclar Vivadent). Low speed rates were used to fire the glaze. Fired at 35 °C to 730 °C for one minute, the glaze was then slowly cooled at 25 °C per minute andfinallyheldat350°Cfor15minutes(Fig.19). Next, the crowns were glazed with shades one and two of copper, white, cream, profundo, ma- hogany, ocean and sunset, then baked at 775 °C per one minute hold (Figs. 20–25). _Seating Once the patient was satisfied with the co- lour, phonetics, and smile line (Fig. 26), the case was prepared for bonding. The zirconia and tita- nium were primed (Monobond, Ivoclar Vivadent) to create mechanical and chemical retention in both materials. The case was then cement- ed using universal adhesive implant cement (Multilink Implant, Ivoclar Vivadent, Figs. 27–29).