To evaluate the translucency of several monolithic zirconias (MZ) processed in various
sintering ovens designed for single-visit, chairside use.Discs (n=40) from zirconia
blocks were fabricated for each MZ at manufacturer-recommended minimal thicknesses,
as provided in each material's instructions for use: IPS e.max ZirCAD LT (ZLT); CEREC
Zirconia+ (CZ+); 3M Chairside (3M); KATANA Zirconia (KT). Groups (n=10) were sintered
following manufacturer instructions for each oven: CEREC SpeedFire, Ivoclar CS4, Ivoclar
CS6, and Ivoclar S2 (laboratory furnace control). Specimens were highly polished on
one side and glazed on the other. Each side was measured with a spectrophotometer
against white and black backgrounds to determine translucency parameter (TP) and contrast
ratio (CR) values. Results for TP and CR for each material and oven combination were
compared with a linear mixed model. Oven precision was evaluated using the Kruskall-Wallis
test.Glazed specimens were more translucent than polished ones (p < 0.001). ZLT and
CZ+ were more translucent than 3M and KT regardless of the sintering oven (p < 0.01).
Several oven/material combinations reached or exceeded the S2 oven TP: CS4 with CZ+
and 3M; CS6 with ZLT and KT (p < 0.01). SpeedFire was significantly less precise (p
< 0.05) and produced lower TP values for ZLT, CZ+, and KT (p < 0.01). Results for
TP and CR were highly correlated.MZ surface finish, material thickness, and oven used
all had a significant effect on translucency. Some chairside-oriented solutions produced
results with translucency equal to conventionally processed zirconia.The translucency
of a ceramic restoration is an important factor in determining its esthetics. Clinicians
desiring the most esthetic outcomes with monolithic zirconia should be aware of the
significant effects; surface finishing, material thickness, and sintering oven use
can have on restoration translucency.
