“I’ve only been working with CEREC Connect for a few months now,” said Dr. Gillespie. “But the outcome of the restorative treatment has been so positive. The restorations are beautiful, the fit is superior, and turn-around is a single day in some cases.” He credits Buffum’s willingness to invest in compatible technology and the artistry of the laboratory-fabricated restorations as the primary reasons he’s foregoing CEREC’s biggest advantage of same-day restorative treatment.

Dr. Gillespie and Mike Buffum are among the growing number of dentist/laboratory teams taking advantage of new technologies allowing the transfer of digital information from chairside to the laboratory or providing the ability to capture and digitize information directly from traditionally prepared impressions.

The recent introduction of the Cadent iTero (www.cadentitero.com) and 3M ESPE Lava C.O.S. (www.3MESPE.com/LavaCOS) chairside digital impression-taking technologies, along with the introduction of CEREC Connect Internet portal and impression scanners such as Zahn Dental’s Dental Wings DWOS (www.zahndental.com) or the Optimet scanner from Nobel Biocare (www.nobelbiocare.com) that can convert conventional negative impression information into positive virtual models on-screen, have opened the door for dentists and laboratories to transmit case information digitally or transform impression information into a digital format. From the digitally captured information, the laboratory can CAD design the case as well as receive a 3D printed or milled model to use for conventional fabrication techniques or for scanning if the case requires zirconia milled substructures or 3D printed wax substructures for casting or pressing.

Nelson Rego, CDT, owner of Smile Designs by Rego located in Sante Fe Springs, Calif., works with both the chairside digital impression capture technology and a scanning technology that digitizes conventional impression information. This allows him the versatility to service not only early adopters of digital impression-taking technologies but also those GPs who prefer to take conventional impressions.

In either case, he uses his in-house Dental Wings DWOS scanner to accept STL files from Cadent iTero users for case design or to scan a conventional impression, converting it into a virtual model. Once Rego designs the restoration, he sends the information to Custom Milling Center (www.custom-milling.com), located in Arvada, Colo., for the manufacture of a 3D model, printed on the newly introduced Zahn Dental EnvisionTec Perfactory Xede 3D model printer, and for the restorative assemblies the case requires, including a zirconia substructure, wax copings, or wax bridge framework for casting or pressing.

“We’ve been working with the chairside CEREC system and milling our own crowns for several years,” said Dr. Gillespie. “So the only difference in our protocol is sending the digital information to the laboratory instead of to our milling machine.” The scan information is downloaded from the CEREC unit by his dental assistant and then taken to a computer hooked up to highspeed Internet where the CEREC Connect portal is accessed. There, Gillespie fills out a prescription form with the shade, the patient’s last name, and any other case information.

Dr. John Walker, who operates a practice in Olympia, Wash., works with the 3M ESPE Lava C.O.S. digital impression-taking device. He had used the chairside CEREC unit for years and says that experience was an advantage in the learning curve for using the Lava C.O.S. unit. After a two-day training period, it took about a week working in tandem with a C.O.S. trainer before he obtained certification to use the system to produce actual cases.

Dr. Walker’s two assistants do the actual scanning, which frees him to see other patients while they scan the preparation, then scan the opposing arch and the bite. He then quickly checks the scans before they are sent to his laboratory.

“The beauty of a digital impression is that you immediately see what has been scanned on-screen,” he said. “This is not like looking at a conventional impression where you look at it and think ‘Well maybe I got the margin, maybe I didn’t’. You know immediately if you captured all the needed information. If you need to take another scan, it only takes 60 seconds. With a conventional impression, you have to take what you get or do it over. That means repacking the cord, cleaning the prep site, mixing a new batch of impression material, taking another impression and letting it set up for 6 minutes, taking it out, and checking it again.”

There are challenges to digital impression-taking, but, according to Dr. Walker, the challenges are no different than those faced when using traditional impression-taking methods. Getting the tissue out of the way and controlling fluids are paramount to capturing a good margin using either technique. “There is no technology that will do all the work for the dentist,” said Dr. Walker. “Digital is not a magic wand. And the lab can’t work with something that’s not there.”

But, if done properly, the end result according to both Drs. Gillespie and Walker, are restorations that need little if any adjustment.

“The accuracy we see in restorations fabricated from a digital impression is amazing because there is no possibility of distortion as there is when working with traditional impression material and dental stone,” said Dr. Gillespie. “And when you can save time on both the front end and back end of an appointment, that means more available time to see patients and prep teeth.”

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