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He reduced the axial and occlusal by an average of 1.5mm (the minimum thickness considered ideal for full contour zirconia restorations is 1.0mm) and created a definitive finish line, a shoulder with rounded internal line angles or chamfer, and rounded all the sharp edges and line angles.
Dr. Harnois took digital impressions and sent them with the photographs and shade information to Sundance Dental Laboratory and fitted the patient with an appropriate provisional restoration.
Upon receiving the milled restoration, Sundance slightly adjusted it using grinding instruments with little or no pressure and water to prevent excessive heat that can cause the zirconia to fracture.
To create a clean surface so the stain and glaze adhered to the crown, the zirconia surface was sandblasted with alumina (no coarser than 50µm at pressures not exceeding 50psi is recommended). The crown was steam cleaned for several seconds to remove surface contaminants (an ultrasonic cleaner can also be used).
Restorative Challenge: The female patient presented with a fractured tooth #30. Because the restoration on the opposing tooth was a PFM, a full contour zirconia restoration was deemed appropriate (she is a bruxer) and offered better esthetics than the PFM.
Laboratory Protocol: The laboratory digitally designed the full contour crown and sent the file to Diadem for milling; the models were milled simultaneously with the crown.
The laboratory used the shade tab, patient photograph and DiazirTM Full Contour Zirconia Stains and Glazes to ensure a polychromatic natural appearance. Because this was a posterior tooth, the stain was applied to the occlusal fossae along with the pits and fissures. The Diazir system includes a Shade Coordination Chart that recommends the appropriate stain for each desired shade and a Firing Chart detailing all necessary parameters; in this case, the firing parameters for staining and glazing were the same.
Steven Dearien, CDT, began his career at age 15 as an in-house technician and five years later, in 1987, he opened Sundance Dental Laboratory in Scottsdale, AZ. Since then Dearien has grown the company to include a team of 42 dedicated employees. He credits the laboratory’s success to a simple philosophy: provide a great product with excellent customer service. He is noted for his exceptional technical skills and teaching techniques.
Chairside: Dr. Peter Harnois determined the appropriate shade and took photographs in order to communicate with Sundance Dental Laboratory.
After firing, the full contour zirconia restoration appeared smooth and glazed. However, if the proper surface texture had not been achieved, Diazir Full Contour Zirconia Glaze could have been re-applied and re-fired according to the parameters.
(To prevent damaging the restoration surface, Diadem recommends the use of specific zirconia polishers: NTI CeraGlaze or Zir-Cut Zirconia Polishers from Axis Dental and Jota Porcelain Polisher by Jota AG. Additionally, specialized zirconia polishers are available from Komet and Brasseler. If polishing paste is required, DiaShine Diamond Polishing Compound (fine) from VH Technologies is recommended.)
Dr. Harnois removed the provisional restoration, cleaned and dried the preparation and tried in the Diazir restoration to verify the fit and contacts. He used Ivoclar Vivadent’s Multilink cement to seat the restoration. (If a higher level of adhesion had been desired, self-adhesive and adhesive resin cementation systems could have been used.) The patient was very pleased with the results and happy to have a long-lasting, well-made restoration.
About Diadem Precision Technology Diadem Precision Technology is a milling center offering DiazirTM Full Contour Zirconia Copings and Frameworks and IPS e.max CAD lithium disilicate, all milled with Röders industrial precision milling systems. Founded by Mike Girard, RDT, in 2009, Diadem is an authorized Ivoclar Vivadent milling partner and authorized reseller of 3Shape Dental Systems. It has locations in Troy, MI, and Windsor, ON. For more information, call 888-9DIADEM (888-934-2336) or visit www.diademprecision.com; for technical support, call 800-922-5520.