Translucency of zirconia copings made with different CAD/CAM systems

Baldissara, Paolo; Llukacej, Altin; Ciocca, Leonardo; Valandro, Felipe L.; Scotti, Roberto

doi:10.1016/S0022-3913(10)60086-8

« Previous Next »Journal of Prosthetic Dentistry
Volume 104, Issue 1 , Pages 6-12, July 2010

Translucency of zirconia copings made with different CAD/CAM systems

Paolo Baldissara, DDS
- Professor, Department of Oral Sciences, Section of Prosthodontics, Alma Mater Studiorum University of Bologna, Bologna, Italy
- Corresponding author: Dr Paolo Baldissara, Alma Mater Studiorum University of Bologna, Department of Oral Sciences, Section of Prosthodontics, Via S. Vitale 59, 40125 Bologna, ITALY, Fax: 0039 051 225208
Altin Llukacej, DDS
- Granted Tutor, School of Dentistry, Department of Oral Sciences, Section of Prosthodontics, Alma Mater Studiorum University of Bologna, Bologna, Italy
Leonardo Ciocca, DDS
- Clinical Assistant Professor, Department of Oral Sciences, Section of Prosthodontics, Alma Mater Studiorum University of Bologna, Bologna, Italy
Felipe L. Valandro, MSD, PhD
- Associate Professor, Division of Prosthodontics, Department of Restorative Dentistry, Federal University of Santa Maria, Santa Maria, Brazil
Roberto Scotti, MD, DDS
- Chief and Professor of Prosthodontics, Department of Oral Sciences, Section of Prosthodontics, Alma Mater Studiorum University of Bologna, Bologna, Italy

Statement of problem

Zirconia cores are reported to be less translucent than glass, lithium disilicate, or alumina cores. This could affect the esthetic appearance and the clinical choices made when using zirconia-based restorations.

Purpose

The purpose of this in vitro study was to evaluate the translucency of zirconia copings for single crowns fabricated using different CAD/CAM systems, using lithium disilicate glass ceramic as a control.

Material and methods

Using impressions made from a stainless steel complete-crown master die, 9 stone cast replicas were fabricated, numbered, and distributed into 8 ceramic ZrO₂ CAD/CAM system groups (Lava Frame 0.3 and 0.5, IPS e.max ZirCAD, VITA YZ, Procera AllZircon, Digizon, DC Zircon, and Cercon Base) and to a lithium disilicate glass-ceramic control group (IPS e.max Press) using a simple computer-generated randomization method. From each die, the manufacturer's authorized milling centers supplied 5 copings per group without applying any dying technique to the ceramic base material. The copings were prepared to allow for a 40-μm cement layer and were of different thicknesses according to system specifications. Translucency was measured by the direct transmission method with a digital photoradiometer mounted in a dark chamber. The light source was a 150-W halogen lamp beam. Measurements were repeated 3 times for each specimen. Data obtained were analyzed using 1-way ANOVA and the Bonferroni multiple comparison test (α=.05).

Results

Among ZrO₂ copings, Lava (0.3 mm and 0.5 mm thick) showed the highest (P<.05) values of translucency measured as light flow units (3.572 ±018 × 10³ lx and 3.181 ±0.13 × 10³ lx, respectively). These values represent 71.7% and 63.9%, respectively, of the glass-ceramic control group (4.98 × 10³ lx).

Conclusions

All ZrO₂ copings demonstrated different levels of light transmission, with the 2 Lava specimens showing the highest values. Translucency of zirconia copings was significantly lower (P=.001) than that of the lithium disilicate glass-ceramic control. (J Prosthet Dent 2010;104:6-12)