Through the widespread acceptance of CAD/CAM and full contour zirconia (FZ) restorations, it is important to understand the availability and advantages of zirconia specific rotary instruments. Utilizing the correct tools for processing milled green state zirconia, and the post sintered zirconia, provides an opportunity for product enhancement. Through the use of these zirconia specific rotary instruments the availability of all needed tools is now complete. Now, let’s look at getting the most out of full contour zirconia.
Providing high end FZ restorations obviously begins with a great material, design and milling strategy. That said, there are significant enhancements one can add to the product using little time and some additional knowledge. Utilizing the best tools and materials will further enhance the product, and do so very efficiently. In fact, one of the primary reasons that zirconia is the fastest growing indirect restorative material is cost and low labor.
For full contour zirconia, the analog process begins after the milled zirconia is removed from the disk. In the green state, zirconia is quite soft and easily trimmed. Adjustment of the extra margin thickness is accomplished with HE Silicone™ Carbide Infused wheels and points (Fig 1). The GS Contour 2 step instrument may be used at the final connection point between the sprue and actual restoration. This leaves an ultra smooth surface. For refining embrasures, it is best to use a friction grip pointed diamond (ZD1C OR ZD2A, Fig 2) at a slower speed or the same shape in a hand piece slow speed tool (ZHP1C or ZHP2A - Ref HP chart). Additional green state adjustments or detailing such as subtle contouring, touching up occlusal anatomy and surface texture can be easily added with the ZD2F or ZD1C (Fig.3 & 4). Historically, most green state zirconia is dipped into a shading material to obtain a monochromatic color that somewhat matches the desired shade after sintering to better enhance the FZ restoration. Once all final contouring is complete a multi-coloring process can be utilized. Utilizing colorants for green state shading one can multi shade the FZ monolithic restoration (fig. 5). By nature, green state zirconia is quite absorbent. This absorbent property results in the colorants penetrating the surface of the material. By following the protocol one obtains the advantages of a monolithic restoration that is multi shaded.
Once sintered, all adjustments made with diamonds should be done with irrigation, so as to prevent introducing micro fractures into the restoration. First, crowns should be carefully tried on the die. Generally there is no adjustment needed. However, in the event of a prematurity, it is recommended to utilize a fit check paint or spray. Adjusting of axial walls or occlusal surface can be accomplished with a ZD1D high speed diamond and irrigation (fig 6). Proximal contacts can be fine tuned and occlusal adjustments can be accomplished with a 1 mm round high speed diamond (ZD4D). Due to the hardness of zirconia it is critical to polish the surface of the restoration prior to final stain and glaze. Zirconia manufactured for dental is extremely homogeneous.This results in a surface that can be polished to a super smooth surface. For final contouring it is recommended to use a RedBerry (Coarse) followed by BlueBerry (Medium) and GoldenBerry for high shine polishing( Fig 7). The Berrys actually leave a smooth surface as they reduce and contour. These instruments are also available in points for high shine polishing occlusal detail. Final stain and glaze may be accomplished with polishing compound.
Once the crown is delivered to the dentist it is just as important that any pre and or post insertion adjustments made by the dentist are also polished. The Wagner dentist ZR / LD chair side adjustment kit contains all the necessary tools for final intra oral adjustment and polishing.
With proper handling of zirconia by both the laboratory and dentist, these super high strength materials will offer patients years of service working in harmony with existing dentition.
Bob Cohen, CDT
Bob, a dental technician for 40 years and cofounder of CAP - Custom Automated Prosthetics, (an outsource milling and digital Solution Company) and founded Advanced Dental Technologies (ADT) in 1982 where he has been a consistent provider of high quality prosthetics to the dental community. Bob has had the opportunity to speak internationally on topics such as Functional Esthetics, Implants, Occlusion, Dental Economics and Digital Applications in Dentistry and the Dental Laboratory. He has developed processes for dentistry and holds several patents. Bob has authored and coauthored several articles on many developments in the dental and dental technology fields.
Bob Cohen can be contacted at