Clinical Concerns and Common Misconceptions Regarding Zirconia Restorations

Perhaps the most significant change in restorative dentistry this decade has been the large-scale, widespread permeation of zirconia into everyday practice. Several factors have propagated the success of this material, including the rising cost of precious metals, increased demand for esthetics, advancements in digital design and laboratory milling, new techniques for bonding, and developments in dental zirconia. Zirconia has been compared to steel because of the toughness it achieves through a process termed transformation toughening. Yet, despite zirconia’s excellent mechanical properties, its use as an acetabular cup in hip implants was ill-fated due to excessive wear following surface roughening from unwanted phase transformation. To avoid the clinical failures and legal ramifications experienced by the orthopedic field, dentists should have a basic understanding of the properties of zirconia in relation to clinical procedures. This article provides a simplified explanation of the structure of zirconia and how that structure affects several clinical situations. It also presents and discusses common concerns and misconceptions regarding zirconia.

LEARNING OBJECTIVES:

• Describe the structural composition of zirconia and how this affects its strength and long-term performance

• Discuss the effects of particle abrasion and bur adjustment on the strength of zirconia and why zirconia causes less wear to opposing enamel than veneering porcelain

• List reasons for fracture of veneering porcelain on zirconia and how to avoid it

• Identify burs for removing and accessing through zirconia crowns, and describe preparation guidelines for a zirconia crown

About the Authors

Nathaniel Lawson, DMD, PhD
Assistant Professor and Director of Biomaterials Residency, University of Alabama Birmingham (UAB) School of Dentistry, Birmingham, Alabama

Chin Chuan Fu, DDS, MS
Assistant Professor, University of Alabama Birmingham (UAB) School of Dentistry, Birmingham, Alabama