Appropriate Handling of Monolithic Zirconia Restorations Pre-Insertion

In fact, Glidewell Laboratories (Newport Beach, CA) reports that 72.3% of all restorations fabricated in 2018 were full contour zirconia restorations.1  Perhaps it is the excellent mechanical properties or the decreased lab fee associated with these restorations that has led to the popularity. Regardless of the reasons, these restorations are serving our patients very well.

With a flexural strength of greater than 900 MPa for most zirconia restorations, strength is not an issue; however, the opposing strength and wear become a concern for many practitioners especially against enamel. It has been confirmed through validated studies that the opposing wear of zirconia may be not as detrimental as one may think. In a study published in 2013, the wear of zirconia and other materials was analyzed against enamel. It was found that the most wear against opposing dentition was veneering porcelain, followed by glazed zirconia. Enamel caused moderate opposing wear, yet the least amount of opposing wear was cause by polished zirconia.2

With the aforementioned results taken into consideration, it is imperative that we remove all glaze on the occlusal surface of our zirconia restorations. One may also request that the restorations not be glazed on the occlusal surface; however, this request is not always adhered to by the lab or it may not be possible to exclude the occluding surface while glazing. The ASAP Indirect+ All Access Surface Polishers by Clinician’s Choice are an excellent choice to insure removal of the glaze prior to or following final cementation. These polishers have been designed with a high concentration of diamond particles coupled with a durable silicone binder. They are ideal for zirconia, as well as all other ceramic restorations. They have diamond-impregnated adjusters and polishers which both allow easy access to all surfaces. In addition, the adjusters and polishers are available in both intra- and extra-oral handpiece configurations. 

 The restoration(s) should be tried in and both interproximal and occlusal contacts should be adjusted. Following adjustments, the adjuster is used to remove any scratches made by a diamond bur, as well as insure the glaze is removed (Fig 1 and 2). Following the use of the adjuster, the pre-polisher (blue) is used to smooth and initiate the polishing process (Fig 3). Once pleased with the pre-polisher, the final polisher (pink) is used to create a beautiful lustre in a matter of seconds (Fig 4 and 5). Figures 6 and 7 show the final restoration seated following polishing.

Adherence to this technique will allow the clinician to place long-lasting, durable restorations with excellent mechanical properties. Literature has proven the minimal wear of zirconia restorations. Don’t be fearful of zirconia as it has many benefits to both the clinician and patient. 

 References: 

1. Data on file, Glidewell Dental Laboratories, Newport Beach, California. Accessed November 20, 2019. 

2. Janyavula, S, et al. The wear of polished and glazed zirconia against enamel. J Prosthet Dent. 2013 Jan;109(1):22-9