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CASE OF THE WEEK: Episode 32
A Disastrous Double-Arch Impression Tray
– ARTICLE by Michael C. DiTolla, DDS, FAGD
When dentists attend my lectures, they are often fascinated by the clinical cases I show of what other dentists
are sending in to Glidewell Laboratories. “Chairside Live,” our weekly Web series, is a great opportunity for
me to share these cases with dentists on an ongoing basis. Episodes can be viewed online and on demand at
www.chairsidelive.com, or on YouTube and iTunes. If you aren’t already a viewer, I encourage you to start watching now
for informative case examples from our lab and intriguing dentistry-related news stories.
The video stills that follow highlight an interesting Case of the Week from Episode 32 that addresses what is probably
my biggest dental pet peeve: when a double-arch tray is used for a bridge impression. While double-arch impressions
can be suitable for one single-unit crown or two single-unit adjacent restorations, they should never be used for a bridge.
A closer look at the case illustrates why.
Figure 1: When walking through Glidewell’s crown & bridge department
the other day, I stopped to ask a technician what one thing dentists do in
cases they send to the lab that drives him crazy. “I’m glad you asked!” he
said, and handed me this impression.
Figure 2: Looking closer at this impression, we can see that it is for a 4-unit
bridge, but it was taken in a double-arch tray. I learned from Dr. Gordon Christensen
many years ago that this is a no-no, and now this technician wants me
to know that he dislikes this technique just as much as Gordon does.
A Disastrous Double-Arch Impression Tray39