Superstructures for single-tooth implants

In modern dental implantology, aesthetics are becoming increasingly important. Improved aesthetic results can be achieved as a result of the wider variety of materials, designs and techniques available for implant restorations today. There is also a wider selection of implant abutments, including CAD/CAM, UCLA and prefabricated abutments made of different materials such as zirconia, titanium and gold. This article describes singletooth implant cases in which aesthetic superstructures were success-fully fabricated with the IPS d.SIGN■ layering ceramic system.

In order to achieve a natural shape and contour of implant restorations, profound knowledge of the anatomy of teeth and the gingival outline is necessary. A careful examination of the horizontal sections of teeth (Fig 1) reveals that each section is unique and has a different appearance. Ceramists should consider these unique charac-teristics of dental anatomy in order to achieve a natural emergence profile which is in harmony with that of the adjacent teeth (Fig 2).
A customized abutment (UCLA abutment) must mimic the shape and contour of the natural tooth. In this case, the abutment was cast in gold and a ceramic shoulder was applied using IPS d.SIGN materials (Fig 3). In order to ensure a natural-looking gingival outline, the gingival contour on the working model had to be modified (Fig 4). After the fabrication of the customized abutment, the metal framework was created based on a reduced full-contour wax-up (Figs 5 and 6). Prior to veneering with IPS d.SIGN layering materials, the surfaces of the metal frameworks were carefully finished using crosscut tungsten carbide or ceramic-bonded burs. After having blasted the frameworks with 100 μaluminium oxide at two bar pressure and steam-cleaning them, they were ready for the first wash firing or the actual opaquer firing cycle (Figs 7 and 8).

Following this,the fluorapatite glass ceramic materials were built up. After contouring and finishing, surface texture was applied. Finally the restoration was glazed and polished. This is only briefly shown here by means of the Figures 9 to 18.

Summary
When fabricating restorations, it is important to imitate the features of natural teeth. The root and the shape in the cervical area require particular attention when implant-borne restorations are made. Never -theless, the fabrication of implant-retained restorations has been difficult to date, as the metal imposes certain limitations.
Fortunately, a number of manufacturers have developed new materials which open up new possibilities and thus enable results to be achieved that are satisfactory for all the parties involved.
In particular the IPS d.SIGN materials provide outstanding properties which allow the natural tooth shade to be precisely mimicked (Figs 19 and 20).
Consequently, the fabrication of aesthetically pleasing, implant-supported restorations has become considerably easier, as suitable materials are available for each individual case