Partnering for optimal outcomes

March 21, 2012
Vern Tinker
Issue 2

Coming together to enhance the success of restorative computer aided designed and manufactured (CAD/CAM) treatments, Ivoclar Vivadent and Nobel Biocare have formed a partnership based on Ivoclar’s IPS e.max CAD lithium disilicate glass ceramic and NobelProcera™ CAD/CAM technology. Through the use of both companies’ products, restorative treatment can be provided from the laboratory, while unparalleled esthetics, precise fit, and function are delivered to the patient.3-5

Coming together to enhance the success of restorative computer aided designed and manufactured (CAD/CAM) treatments, Ivoclar Vivadent and Nobel Biocare have formed a partnership based on Ivoclar’s IPS e.max CAD lithium disilicate glass ceramic and NobelProcera™ CAD/CAM technology. Through the use of both companies’ products, restorative treatment can be provided from the laboratory, while unparalleled esthetics, precise fit, and function are delivered to the patient.3-5

Pre-Milling Protocol
01 The working model was fabricated following standard procedures, ensuring that the die and model segments were readily removable (Fig. A).

02 The case criteria were confirmed to ensure that proper design specifications were met and contained all the proper information, including adequate reduction, crown shade and stump shade (Fig. B).

03 The case was prepared for scanning with the NobelProcera scanner. The die preps were trimmed to ensure smooth margins that were not grossly undercut, which could create capturing issues leading to an unusable scan.

04 A laboratory putty bite registration was created that would be used as the opposing model during the scan process (Fig. C).

05 The correct position of the putty bite on the preparation model was verified, ensuring that it could be removed and replaced on the model. To allow for complete scanning, the bite was trimmed 2 mm below the occlusal surface, and the exposed surfaces were marked with a black marker to camouflage them from the scanner (Fig. D).

06 To begin the scan, the correct scan option was selected in the NobelProcera desktop, which allowed the technician to enter case information, the type of restoration, the desired material and the shade (Fig. E).

07 The case components were scanned into the software program, beginning with individual pieces, followed by the putty bite positioned on the model (Fig. F).

08 The case was finalized in the software and the scan module was exited (Fig. G).

09 Following the Workflow icons in the C&B Design window, the path of insertion (Axis Insertion) was set up, along with quick reference tooth positions (Unit Alignment). Margin positioning was modified as necessary and verified by selecting the preparation to work on, which highlighted the margins (Fig. H).

10 The Crown Placement tool was positioned to determine basic crown placement (Fig. I).

11 Using the Tooth Selector, the technician chose from a generic tooth pattern or Ivoclar Vivadent and VITA (Vident) tooth patterns (Fig. J).

12 The software allowed for manual crown positioning by placing the appropriate crown on the 3D scan of the tooth preparation, enabling changes to size, position (vertical, M-D, B-L, positioning), and axial rotation (3-axis rotational) (Fig. K).

13 Once the crown was in its proper placement, more specific modifications for cusp deformations, height of contours (emergence profile), and local deformations for occlusion were created. The areas that showed red on the design indicated areas that were too thin, and adjustments were made accordingly (Fig. L).

14 The crown was finalized using the software, which analyzed and alerted the technician of any areas of concern that required modification (Fig. M). After the crown underwent this process, it was electronically sent to the central milling facility to be manufactured.

Post-Milling Protocol
The IPS e.max CAD crown was received from the central milling facility after about 2 days in its blue state (Fig. N).

15 The fit was checked on the die and the margins adjusted if necessary, and modifications were made to the contacts and occlusion as necessary (Fig. 0). With careful designing, the need for these modifications and finishing procedures can be greatly minimized.

16 A combination of green stones, impregnated rubber wheels and diamond instruments were used for finishing, while being cautious not to overheat or shock the restoration (Fig. P).

17 The blue-state crown was filled with a stabilizing paste (IPS Object Fix, Ivoclar Vivadent) and placed on a special crystallization tray (Fig. Q), after which it underwent crystallization at 850°C/1,562°F for 20-30 minutes.

18 The shading die was fabricated from IPS Natural Die Material (Ivoclar Vivadent), a natural die material to assist in the stain and glaze process.

Shading and Glazing Options

To begin the stain and glaze process, it was necessary to understand the several different options available, including simple glazing to multiple stain and glaze techniques. The decision made should depend on the shade requirements of the case.

When doing a basic stain and glaze, a coat of regular or fluorescent IPS e.max Ceram Glaze paste or powder would be applied.  The regular glaze would be used for a regular or lower-value crown and a fluorescent glaze for higher-value crowns, with the required stains to modify the shade according to the prescription. In a case requiring detailed shading, a basic wet shade/glaze would be applied and set, followed by detailed characterization staining using the appropriate IPS e.max essence stains and a final glaze.

Final Adjustments
Once satisfied with the stain and glaze, the crown was placed on the model, final adjustments were made, and the crown was etched and sent for final cementation (Fig. R).

The IPS e.max CAD crown was seated in the patient’s mouth and demonstrated excellent function and esthetics (Fig. S).

Conclusion
Using advanced CAD/CAM technologies, technicians can create naturally appearing restorations in the least amount of time.1,2 With a greater understanding of the functional forces that are placed on crowns and other prosthetics, technicians now can be sure that their restorations will provide the function and longevity, along with the esthetics, demanded by patients today.1,2

Through partnerships like the one between Ivoclar Vivadent and Nobel Biocare, dental professionals can expect continued advancements in the field of restorative dentistry, which will allow the best of care for patients and ease-of-use for technicians and dentists.3-6