With progress in dental materials manufacturing, the demand for esthetics is increasing – both with the patient and the practitioner. For decades, the gold standard for fixed prostheses was the metal-ceramic crown. However, zirconia crowns have ushered in greater demand within the past 10 years, due to their superior esthetic quality, especially in anterior restorations.
Previously, because zirconia cores did not have the ideal translucency, they were always layered with porcelain. This made these restorations weaker, as we could not achieve strong adhesion between the two materials. To solve this problem, “all- ceramic zirconia” fixed prostheses were introduced.
Even though they look good, can they stand the test of time?
This question was researched by Limones et al. The study conduced a systematic review and meta-analysis of 330 participants, comparing 177 zirconia- ceramic and 173 metal ceramic fixed dental prostheses. Any significant differences in complications associated with each were compared in the medium term (3-5 years).
The study focused on the following parameters:
-Patients who were partially edentulous in the posterior region.
-3-5 unit Zirconia-ceramic and Metal-ceramic restorations only were considered.
-Technical, biological, esthetic and survival rates were evaluated.
-The tooth preparation designs considered were controlled for, and the majority of the cases were cemented with a resin-based cement.
The study showed no significant differences between the two types of restorations when evaluating biological complications (pocket depth, periodontal attachment levels and loss of vitality of the teeth involved).
In zirconia- ceramic restorations, there was an increased incidence of veneer chipping with a rate of 22.3%. However there was no difference in the amount of occlusal wear.
The study also indicated a 95.4% survival rate for zirconia –metal and 96.9% survival rate for metal-ceramic. Therefore, from this study it can be said the zirconia- ceramic restorations are stable in the medium term, however veneer chipping has to be a factor to be evaluated. Due to their superior esthetic quality, zirconia crowns and bridges can be used confidently to give our patients