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Inside Dentistry
July 2015
Volume 11, Issue 7

Better diagnosis can be achieved in many ways through the use of digital technologies. One example is Logicon from Carestream, which is a computer-aided radiographic caries diagnosis software. Digital images can be enhanced through filters in the software to make diagnosing easier. The software scans the radiographic bitewing image and applies an algorithm on all eligible interproximal surfaces to generate a view of potential caries.

Digital panoramic 2D images and cone-beam 3D imaging are also changing the diagnostic landscape. Digital panoramic radiographs can now extrapolate bitewing radiographs using the imaging software. So there is no need for additional radiation to the patient. In keeping with the ALARA principle (“as low as (is) reasonably achievable,” which means making every reasonable effort to maintain exposures to ionizing radiation as far below the dose limits as clinically practical), we are enhancing our diagnostic abilities while reducing patient exposure. 3D images allow for enhanced diagnostics, especially when placing implants and removing third molars.

Digital intraoral photography using both intra- and extra-oral cameras instantly provides enhanced visualization that allows us to maintain the appropriate documentation for medical/legal considerations in addition to improving diagnosis. The ability to have static images that can be magnified should be considered for all new patients and especially for patient education. All of these images become part of the patient record and can easily be recalled in the software when needed.

Caries diagnostics is on the cutting edge of advances in digital technology. Intraoral cameras such as Air Techniques’ Spectra, Acteon’s Soprolife and Soprocare, Carestream CS 1600, and the Canary System from Quantum Dental Technologies are the latest in digital dental diagnosis. Through the use of magnification and both white light and fluorescence, images can be reviewed for fissure caries and stored for later comparison. This allows for monitoring of caries and better treatment decisions. Another new device to enhance caries diagnosis is DEXIS CariVu. This is a trans-illumination device that allows you to see caries without the use of radiation. The photo can be stored in the imaging software and used to see if the carious lesion is growing or is arrested.

A diagnosis is made after a very thorough evaluation of the patient and after all diagnostic tests are complete. No matter how high tech a device is, the decision to treat a patient is made by the dentist and should not be abdicated to a machine.

A Closer Look at Digital Workflow

As Dr. Shuman explained, the concept of digital workflow has been evolving for some time and often means different things to different stakeholders. Digital diagnostics as described above provide many key advantages for enhanced efficiency and patient care, but the benefits of digital technology do not stop at the diagnostic stage of the typical restorative workflow.

Digital Impressions

The latest addition to digital dentistry is the impression system using wands that capture images of prepared teeth and are used to acquire a digital impression of the teeth. There are also impression and model scanners, which scan a standard impression or model to achieve the digital model. The latter may serve as a more comfortable point of entry into this step of the digital workflow for some clinicians. Some clinicians may not be aware that their current restorations have been scanned and fabricated this way, as most dentists and labs still like to produce models.

These digital impressions can be used for fabrication of orthodontic appliances or aligners, along with restorative prosthetics such as inlays, onlays, crowns, bridges, implants, and dentures.

After a tooth is prepared for the restoration, the margins must be visible to the camera. You still need good hemostasis and may need to use retraction cord. Remember, if you cannot see the margin, neither can the camera, which is quite different than conventional impression techniques. After proper preparation, the digital impression can now be acquired with the camera. In many cases, the use of the camera is more comfortable to the patient than using impression material. Using digital impressions, there are no distortions or margin inaccuracies. Should you feel an area is not adequately visualized in the digital impression, it is very simple to just rescan the area in question. Digital impression software can check for proper occlusal clearance and notify you immediately if any correction to the preparation is necessary. All of these enhancements will save you time, because there will be fewer remakes and less time delivering the restoration, as the contacts and occlusion should be more accurately reproduced.

Milling Considerations

Digital impression systems produce files, not impressions, and these files maybe in an open or proprietary (“closed”) format. The open systems produce STL (stereolithography) files, which can be shared with any laboratory or chairside milling system to produce a restoration. Closed systems keep you locked into specific milling machines and/or labs that have acquired the mills to produce that company’s restorations. If the restoration is to be milled at the lab, using a digital impression will save you money on the shipping costs to the lab and also may see reduced turn around time. Some labs will even reduce the cost of the restoration if you get a “crown in a box.” What this means is that no model has been produced, similar to what you do with in-office milling.

When considering in-office fabrication, there are advantages to buying the scanner and mill from the same company. Some companies, including Planmeca, Sirona, and Carestream, offer both scanners and mills. (However, this doesn’t necessarily mean that the system is a closed system—see the enclosed Product Resource Guide for more information.) Some of the advantages of the same-manufacturer approach include being assured the products will work together and getting tech support from one place.

If you choose an open system, then you can pick the scanner that you want from one manufacturer and choose the milling machine from another company. Some dentists may prefer to purchase a scanner and a mill from different companies because this allows flexibility. Practices get to choose which parts of the impression or CAD/CAM equipment from each manufacturer work best for them. Buying “a la cart” may mean decreased costs, but the there is a possibility of increased IT issues. Some companies assist with this approach, such as Benco’s OneVisit system, which includes the 3M™ True Definition Scanner used with the IOS Glidewell TS 150™ mill. In addition, there are lower cost mills from Roland (between $15,000 and $30,000) that reduce the barrier to entry. You will need to select the mill that is appropriate for the restorations that you are looking to produce.

When using in-office mills, you will need to understand the limitations of your system and select the appropriate milling blocks. During treatment planning, you will need to determine treatment issues such as occlusion and restoration type (eg, inlay, onlay, or crown) and select the appropriate block for each case. For example, you will not, in most cases, be able to mill zirconia restorations, meaning that you may still need a laboratory for fabricating some crowns. Most dentists are currently using Ivoclar Vivadent IPS e.max® (lithium disilicate) CAD blocks for crowns, inlays, and onlays. These blocks are strong and have good esthetics. They are tried in and adjusted in the patient’s mouth and then stained and glazed in an oven. The restoration is then bonded or cemented into place.

Final Delivery

The final piece to the restorative digital workflow is to check the occlusion. Through the use of the Tekscan T-Scan, you can perform a digital occlusal analysis. You can actually determine not only the points of contact but also see how much force is being generated. This is a level of detail that cannot be obtained using any articulating paper. The mini movies it produces allow you to store and view the actual occlusal contacts and forces.

Final Considerations

Digital technology makes sense for both the patient and practice. There are increased efficiencies. Digitizing data can make for faster retrieval of information when making critical diagnostic decisions, along with increased accuracy of treatment. The digital workflow will distinguish your practice form others, because in many cases these digital advances allow for a better patient experience.

About the Author

Martin Jablow, DMD, is a clinician, speaker, and author. He presents and publishes worldwide on many topics, including state-of-the-art dental technology and dental materials. Dr. Jablow is president of Dental Technology Solutions, a lecture and consulting company. He is an active member of the American Dental Association, New Jersey Dental Association, and Middlesex County Dental Association, and has achieved Fellowships in the Academy of General Dentistry and International Academy of Dental Facial Esthetics. As the Internet has grown, so has Dr. Jablow’s online presence with his dental blog, webinars, and as host of TakeFiveWithMarty.com.

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