Digital Impressions

The following is excerpted from an article I wrote for Dental Economics:

untitledThe most important element a dentist needs to understand about new digital impression technology is not whether or not it can make a crown like we used to or how the technology works but simply that it is digital. That changes everything – that is the Aha. To understand the advantages of digital impressions let’s compare it to another digital system you have probably already used and understand; a digital photograph.

Infrastructure: Back in the olden days, you know, last century, BC (before computer) we took photographs with a film camera. This required a complex infrastructure that was purpose built and exclusive to photography. That is the film, the camera the chemicals the processing equipment and the printing materials were all exclusive to photography. In other words you could not use the photography system to send a post card or take an impression.

Conventional impressions also need single purpose systems from trays to impression materials and various stones, vibrators, mixers and vacuum pumps to create a model. You cannot use the impression system infrastructure to send a postcard or take a photograph.

Since the infrastructure is single purpose, complex and expensive most people do not try and do it themselves. They instead send the film to a special lab to be processed and printed.

Of course the same is true of impressions. Most are sent to a special lab to be processed and the restoration created.


Process: In addition to the infrastructure there was the process. You would take a photo but you would need to put it through a long and complex process of developing and printing before you could use it, usually hours or even days later. If there was an error, like poor focus or over exposure, you would not know about it until the photo was developed printed and returned to you. Then of course it was too late to fix it. If the photo was unneeded or just ugly (Aunt Tilly blinked) too late you already spent the time and money to create it.

The conventional impression process is similar. You take the impression but do not get to see or use the model for hours or days later. If there is an error, a bad margin a void or distortion it is too late to fix it.

Storage: Once you finally get the film photo print or slide that you want you then have to store it. At home that means throwing the snapshot in a shoebox randomly with all the rest or taking the time to put it neatly in a photo album. At the office it means labeling and dating the image and putting it in a patient chart.

Impressions are even harder to store. They need to be labeled, dated, boxed and stored on shelves in a manner where they can be found later. Because this is so tedious most models end up stored with the random shoe box technique or just thrown away.

Distribution: If you want to send a film photo to a friend or a clinical film photo to a colleague then it would need to be copied back at the lab, put in an envelope and mailed. The process would be expensive, the quality of the image would be degraded and it would take days to accomplish.

Sending a copy of an impression would be similar but even more complex time consuming and expensive.

Digital: With digital photography everything changes. The infrastructure is a computer network. This digital infrastructure can be used to capture, process, display, store and transmit the photograph. However it can also be used to send a post card; that is an e-mail. It can be used for impressions, records, diagnostics and a whole lot more.

With the digital photo process the user can see the image immediately. If there is an error it can be corrected right now. There is no need to pay the processing costs simply hit the delete button. The same is true of a digital impression. The user sees the image immediately and can make corrections if they are needed and discard the mistakes.

Digital photos don’t fill up shoe boxes or bulge out of files but are stored as part of the patient record on a hard drive. Digital impressions can also be stored on a hard drive. The storage process usually requires three or four mouse clicks and the hard drive is smaller than a shoe box and costs less than a file cabinet.

Sending a digital photo to a friend or colleague can be done online with just a few mouse clicks. It costs nothing, it happens instantly and the image is exactly the same quality as the original. The same is true of a digital impression.

Applications: CAD-CAM stands for Computer Aided Design and Computer Aided Manufacture. These systems take a digital impression of a prepared tooth and then the computer designs a restoration and mills it out in a special chamber. The result is a one step lab type restoration with no impression, no temporary and no second appointment.

There are two dental CAD-CAM devices available. The first is Cerec from Sirona which was introduced over 25 years ago. The second is the E4D from D4D Technologies.

Another application of this type of technology is a digital impression. A digital impression is simply the first step of CAD CAM; that is the capture of a 3D digital version of a tooth. There are two digital impression devices available. The first is iTero from Cadent. The second is the Lava COS from 3M.

Both iTero and Lava COS are designed with single tooth restorations in mind. However it is possible with Lava COS to take a full arch impression.

Full arch images leads to the final use of virtual 3D models and that is Invisalign. Any dentist who has seen the virtual models created by the Invisalign ClinCheck process has to have been impressed. Imagine having that type of system available in the office to create routine virtual study models. Currently Invisalign still requires an impression which is then scanned to create the virtual model.

Once it is digital everything changes…”Aha”, the future is coming and it will be amazing!

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