How to reliably
Alec J. Ganci, DDS, FICOI
ZIRCONIA WAS INTRODUCED TO DENTISTRY in the early 2000s. For years, it
had been used by the orthopedic industry for prosthetic joints due to its similarity
to titanium, both in terms of strength and biocompatibility. When zirconia was first
used in dentistry, it was regarded as an incredibly strong material used for bridge
frameworks and single-unit copings.
1 However, it was too dull, white, and chalky to
be considered for a posterior restoration—let alone anterior.
2 Luckily for the field of
dentistry, things have changed.
Full contour zirconia (FCZir) now is being used routinely
for everything from anterior single crowns and bridges to
full-arch implant prostheses. Personally, I have found the
esthetics of newer types of FCZir to be just as good as
lithium disilicate, with the added benefits of higher strength
and biocompatibility. The only fixed restorations for which
I’m not using zirconia are veneers.
The problem with zirconia, however, is that when used
in restorations, it has a penchant for falling off after insertion,
sometimes after only a few weeks. To combat this issue,
products had come out that were designed to treat the crown
or the intaglio of the zirconia restoration. But unfortunately,
the results of these products were unreliable. This is because
our industry didn’t have a strong grasp on the mechanics
and chemistry of bonding zirconia.
However, all this seems to be changing. One day, while
using my intraoral scanner (True Definition Scanner, 3M),
I noticed another option suddenly appear from the drop-down menu: Lava Esthetic Fluorescent Full-Contour
Zirconia (3M). I was skeptical to try a new material (as I
always am), but after speaking to my laboratory, we decided to give it a try.
The reasons Lava Esthetic interested us were as follows:
• Inherent, toothlike fluorescence
• High translucency
• Excellent shade match to Vita Classic shades, plus unique
shading technology and built-in shade gradient
• Durable full-contour, with high-flexural strength (800
MPa) and fracture toughness (> 3. 5 MPa/m1/2)
• Strong, reliable bond
The next day, a good case opportunity presented itself.
I had to prepare and scan No. 13 for a crown. I figured it
was anteriorly positioned enough that I could test the
esthetics, but it was posterior enough that the stakes weren’t
too high. Nevertheless, you can see from Figures 1a–1c
that we were thrilled with the results. Additional restoration
examples can be seen in Figures 2 and 3.
SCIENCE & TECH
1a: Prepared No. 13
1b: True Definition
scan merged with
1c: No. 13 with Lava
Esthetic full contour