Making Other Full Contour Zirconias Obsolete
Inside Dental Technology delivers updates on digital workflows, materials, lab techniques, and innovation in dental technology through expert articles and videos.
June 1, 2014
Volume 5, Issue 6, June 2014
Page(s): p. 62-63
For more than a decade, monolithic monochromatic restorations have become the standard of care for most dentists and patients. This is due to the development of high-strength, all ceramic, monolithic materials—such as lithium disilicate and full contour zirconia. In addition to their high-strength, these materials represent a reduction in labor, a lower cost, and fewer manufacturing cycles for many laboratories. Additional benefits of these monolithic materials include the elimination of multiple materials in a single restoration and the interface between them. For decades, dental experts have researched the bond between frameworks and ceramic layering, and this area of the restoration has often proven to be a weak point. By using monolithic materials, laboratories can eliminate this potentially problematic interface.
Since their inception, the many benefits of monolithic materials have changed the scope of the majority of work produced in most dental laboratories. With the advent of these specialized materials, it appears as though the only compromise regarding the final restoration is in the realm of esthetics as a result of the monochromatic nature of the material. Now, for the first time, laboratories have the option of producing a high-strength, monolithic, full contour, multi-colored zirconia restoration with Custom Automated Prosthetics’ CAP Multi FZ.
CAP Multi FZ has been specifically developed to demonstrate excellent strength and esthetics, offering laboratory technicians an MPa of 1100 and layers that closely match the shade gradations of natural dentition, which gives CAP Multi FZ restorations a very true-to-life appearance. Multi FZ zirconia discs are available in the standard 98 mm disc form in several different thicknesses. They are fabricated to include three distinctly shaded layers—a cervical shade, a body shade, and an enamel shade. During disc manufacturing, the different shades are blended with one another, providing a life-like transition between each shade zone in each disc for superior esthetics. The cross section of the disc results in five areas of color and color transition zones (Figure 1). Currently, there are three different shaded discs available to the market, as well as a white disk for bleach shades (Figure 2).
At CAP, technicians use conventional CAD/CAM steps in order to produce a very high-end, monolithic, Multi FZ restoration. Initially, they obtain scan data from either the dentist (using a device such as 3Shape’s TRIOS® intraoral scanner (Figure 3), or they scan physical models (using a 3Shape desktop scanner). Through CAP’s proprietary software, CAPZilla, the digital workflow moves seamlessly through the manufacturing process. CAPZilla allows for reduced data entry, reduced sorting of files, and reduced the potential for human error in a digital workflow. This makes it easy for the CAP team to transition files from the 3Shape scanner through the entire manufacturing process. Utilizing the CAP Anatomic Library, the CAP team is able to achieve best-in-class tooth morphology for every individual restoration (Figure 4).
Once the restoration is designed, CAPZilla places the design file into a folder based on needed disc thickness and shade. This streamlined CAM (Sum 3D) operation is achieved by selecting a new or partially used disk of the correct thickness and shade. For instance, the CAM operator will be presented with several folders that only include STL files that require a 14 mm disc and a particular shade. As production continues, there will be several CAM folders that are automatically sorted by CAPZilla based on the shade of the restoration and height of the STL file.
The disc barcode is scanned and the CAM is quickly completed (Figure 5). The restoration file can also be moved up or down in the disc to increase or decrease the amount of enamel shade represented. Next, the disc is placed into a Roland DWX-50 milling machine (Figure 6) and the milling process begins. Once milling is complete, the restorations are removed from the disc, cleaned, and placed in a sintering tray. Firing of the CAP Multi Z zirconia can be facilitated in almost any programmable sintering furnace. Technicians at CAP use the SINTRA sintering furnace from ShenPaz ( www.shenpaz.com), which offers all of the components necessary to achieve consistent, accurate, and reliable firing of zirconia. These components include bottom entry, Mosi2 heating elements, a user-friendly interface, and the ability to achieve true customization of programs.
After the restorations have cooled, a quick check for fit to the die is performed microscopically. If the CAD parameters and mill are properly integrated, the fit of the restoration to the die will likely be perfect and require no internal adjustment. From there, the margins are thinned and the restoration is polished, stained, glazed (Figure 6), and checked for quality. After these steps, it is ready to be shipped to the customer.
The insertion process is performed like most any other restoration. If adjustments are needed, CAP Multi FZ may require hand polishing, which can be accomplished with conventional ceramic polishing products. Once fully adjusted, the restoration can be conventionally cemented (Figure 7).
Disclaimer: The preceding material was provided by the manufacturer. The statements and opinions contained therein are solely those of the manufacturer and not of the editors, publisher, or the Editorial Board of Inside Dental Technology.
About the author
Bob Cohen, CDT is the President of Custom Automated Prosthetics in Stoneham, MA.
