ACE Panel report finds dentists favor strength of zirconia but struggle with restoration removal

Dentists recognize the favorable fracture resistance and flexural strength properties of zirconia, but restoration removal and shade matching are a struggle for many, according to an  ADA Clinical Evaluators Panel report published in the January issue of The Journal of the American Dental Association.

The report includes responses from 277 ACE Panel member dentists about how they use zirconia in their practices.

"We chose to look at zirconia because of how prevalent this material has become. Our study showed that 99% of dentists who use zirconia use it for natural teeth restorations," said Nathaniel Lawson, D.M.D., Ph.D., one of the report's co-authors and a member of the ADA Council on Scientific Affairs' ACE Panel Oversight Subcommittee. "Additionally, there are now different types of zirconia that have different properties, so dentists can now use zirconia for many different clinical applications."

Nearly all of the responding dentists (98%) said they use zirconia for posterior crowns, while 61% use it for anterior crowns. Regarding bridges, 78% use it for posterior bridges and 57% use it for anterior.

Shade matching and translucency (36%) and restoration removal for replacement (35%) were the top two cited disadvantages of zirconia in the survey. More than half of the respondents (57%) cited flexural strength or fracture resistance as the biggest advantage.

The three most common complications with zirconia compared with metal-ceramic restorations reported by respondents were restoration debonding (52%), opposing tooth wear (31%) and restoration fracture (23%).

"It was surprising to see that over 50% of dentists had more issues with debonding of zirconia crowns than metal-ceramic crowns," Dr. Lawson said. "Zirconia bonded with a correct protocol can have long-term success, according to studies performed on anterior cantilevered resin-bonded fixed dental prostheses."

Ceramic polishers (65%) and fine diamonds (61%) are used most often to polish and adjust zirconia restorations, while coarse diamond rotary instruments (51%) and those made specifically for zirconia (43%) are most frequently used for removing these restorations.

"The survey discovered that the most common instrument used to remove zirconia crowns was a coarse diamond; however, clinicians should consider that zirconia-specific diamonds can be more efficient," Dr. Lawson said.

Dentists can view the entire ACE Panel report online and download the PDF at JADA.ADA.org .

ACE Panel reports feature data from ADA member dentists who have signed up to participate in short surveys related to dental products, practices and other clinical topics. The ACE Panel Oversight Subcommittee of the ADA Council on Scientific Affairs writes the reports with ADA Science & Research Institute staff.

The reports aim to offer ADA members a way to understand their peers' opinions on various dental products and practices, offering insight and awareness on new products and techniques that can benefit patients and the profession.

Members are invited to join the ACE Panel and contribute to upcoming surveys, which occur no more than once every few months and usually take five to 10 minutes to complete.

To learn more orjoin the ACE Panel, visit ADA.org/ACE .