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18 Dental Tribune Middle East & Africa Edition | January-February 2016 aesthetics < Page 16 sal line allows the tooth arches to be integrated more easily in terms of esthetics and func- tion. Impression taking Open tray impressions were taken with a special plaster (Snow White) and unsplinted impression posts. The con- siderable stiffness of the im- pression material completely immobilized the impression posts, which prevented any errors from occurring in the casting of the study models. Articulation of the models The articulator allows the ki- nematics of the jaw to be cor- rectly simulated. The aim of this part of the treatment is of a functional nature. It is in- tended to ensure the optimal occlusal integration of the res- torations and the proper jaw movements during chewing, speaking and swallowing. In this particular case, the up- per jaw model was positioned with the help of a facebow. Four impression posts were screwed on the implants in order to provide strong sup- port and enhanced reliabil- ity. Alternatively, this step can take place directly on the im- mediately loaded provisional restorations. For this purpose, however, the model has to be mounted in the articulator of the dental practice. In the present case, the masticatory model was positioned in the correct relation to the hinge axis-orbital plane. Subsequently, we adjusted the bite patterns in order to re- cord the vertical dimension of occlusion. The centric re- lationship is regarded as the reference position for adjust- ing the muscles to the centric and functional jaw relation- ship. The mandibular model was mounted in the articulator with the help of an antagonist jaw relationship record. If the centric and the vertical dimen- sion of occlusion are correct, the immediately loaded provi- sional restorations can be used for this purpose. The restorations have to be immobilized when they are mounted in the articulator. The Artex system allows the articulator of the dental prac- tice and that of the laboratory to be synchronized. Recording of the major facial criteria the Ditramax® system was used to transfer the pre- cise data related to the esthetic facial axes to the maxillary model (Figs. 5a and b). Two axes were marked on the plas- ter base of the model (vertical and horizontal). The vertical axis represents the sagittal median plane. From the front, the horizontal axis is aligned parallel to the bipupillary line and from the side to Camper’s plane. These markings, which should be very close to the working area, act as a guide for the dental technician in setting up the teeth. Therefore, the incisal line has a predict- able parallel alignment to the bipupillary line. The incisal axis is aligned par- allel with the sagittal/median plane. The Camper’s plane markings indicate the align- ment of the occlusal plane. All these elements provide a sound rationale for the tooth set-up according to esthetic and functional principles. Tooth selection and set-up We selected the tooth shade and the teeth on the basis of the SR Phonares® II tooth mould chart. Holding the teeth up against the lips of the patient quickly reveals whether or not they are in harmony with the facial features. The set-up of the teeth according to the Ditramax markings (Fig. 6) allows the situation to be clini- cally validated. In this case, particular attention was given to the esthetic integration of the dentogingival complex when the patient was smiling. The lip dynamics were shown with video clips. The function- al criteria were also checked. The vertical dimension of oc- clusion had to be harmonious in order to achieve a balanced lower facial third and proper phonation. Fabrication of the framework We felt that a CAD/CAM-fab- ricated titanium framework (e.g. Procera® from Nobel Bio- care) would best fulfil this in- dication. The double scan technique allowed the implant model to be superimposed on the tooth set-up to construct the frame- work. In the next step, the frame- work was machined and then tried on the model and in the patient’s mouth (Fig. 7). The cast impression and the high-performance processing systems significantly contrib- uted to ensuring the optimal passive (tension-free) fit of the framework, which is decisive for the long-term success of the restoration. Preparation of the frame- work for veneering The areas that needed to be built up with Gingiva mate- rials were blasted with alu- minium oxide using 2 to 3 bar pressure. Subsequently, the SR Link bonding agent was applied, followed by a thin layer of the light-curing SR Nexco® Gingi- va Opaquer to mask the metal framework. The opaquer was polymerized and then a sec- ond coating was applied and polymerized. The resulting inhibition layer was removed. The conventional flask tech- nique with a heat-curing den- ture base material (ProBase® hot) was used to produce the denture. After the polymeriza- tion process, the denture base was ground and space was made for building up the Gin- giva composite. The surface was conditioned by blasting it with aluminium oxide (50 μm) at 2 bar (Fig. 8). Then, a bond- ing agent was applied, which was left to react for three min- utes before it was light cured. Veneering of the gingival ar- eas Fig. 14: The complex restoration gave the patient a new lease on life. Fig. 12: The restorations on the implants in the upper and lower jaw Fig. 13: Close-up view: The macro- and microstructure of the teeth and the characteristic play of colour of the gingiva is clearly visible. In order to achieve very lifelike results in the layering of the gingival tissue, saturated (in- tensive) materials were used first (SR Nexco Paste Intensive Gingiva) (Fig. 9). Next, trans- lucent, light-curing Gingiva materials (SR Nexco Paste Gin- giva, SR Nexco Paste Basic Gin- giva) were used to impart the gingival areas with the desired depth (Fig. 10). The colours of he Gingiva composites range from pale pink to reddish and or ange and purple. A certain learning curve is necessary to master the necessary mix- ing techniques and achieve a harmonious interplay of the intensive and the translucent materials. Practice is essential and it will pay off. With some technical skill, the gingival areas can be naturally reproduced in shape, texture and shade. All the individual layers were precured (Quick) in segments. A high-performance curing light was used for the final po- lymerization. Prior to this step, a coating of glycerine gel (SR Gel) was ap- plied to the surfaces to prevent oxygen inhibition, which could lead to an unattractive and dif- ficult-to-polish result. The surfaces of the teeth were characterized with a vertical and horizontal macrostruc- ture. Particular attention was paid to mechanical polishing. Once the glycerine gel was re- moved, the restorations were finished with different polish- ing instruments (various grit sizes, pumice, leather buffing wheels and universal polish- ing paste) (Fig. 11). In the pres- ent case, mechanical polishing was preferred to glazing with light-curing composite in or- der to prevent premature age- ing of the surface. Attachment of the perma- nent dental restorations The dentures were inserted manually with the help of mul- tiunit abutments from Nobel Biocare (Fig. 12). The screw channels were sealed with Teflon and light-curing com- posite resin. The position of maximum in- tercuspation was checked and the occlusal pathways were adjusted to the protrusive and laterotrusive movements. In addition, the restorations were checked in terms of the ability to clean them with interdental brushes, and the patient was given special instructions re- garding her oral hygiene. Discussion For a long time, ceramics were considered to be the esthetic benchmark. With the intro- duction of state-of-the-art in- dustrially fabricated acrylic teeth, which are specially designed for implant applica- tions, the bar for esthetics has been raised in this category of materials. The teeth used in this case exhibit a true-to- nature morphology, which al- lows the restoration to be func- tionally integrated without any problems. Using the laboratory composite SR Nexco to recre- ate gingival tissue is a good restorative approach. In con- trast to ceramic materials, the composite resin is easy to han- dle and delivers exceptionally esthetic results (Fig. 13). The light weight of the material is an added bonus. An all-ceram- ic restoration (zirconium oxide framework, layering ceramic, gingival mask) weighs almost twice as much as a titanium- composite resin denture. An- other advantage of the type of restoration described here is its long service life. Conclusion The success of an implant- retained denture depends on the systematic coordination of all the surgical and prosthetic requirements. A strict procedure needs to be followed from the treatment plan to the final outcome. Lay- ering gingival portions with a laboratory composite repre- sents a genuine improvement on previous materials and methods with regard to esthet- ics, handling and hygiene (Fig. 14). Dr Patrice Margossian 232 avenue du Prado 13008 Marseille France pm@patricemargossian.com Pierre Andrieu 5 boulevard du Roi René 13100 Aix-en-Provence France andrieupi@wanadoo.fr Contact Information “The Artex system allows the articulator of the dental practice and that of the laboratory to be synchronized.” “The success of an implant-retained denture depends on the systematic coordination of all the surgical and prosthetic requirements.”