As with any skill, capturing digital impressions with an intraoral scanner is largely a matter of practice. With the emergence of digital technology as a major part of the dental industry, mastering your scanning technique is more important than ever. Although recent technological advances are making the scanning process simpler and more intuitive, errors can still occur. Fortunately, just providing a little extra effort for digital impressions will lead to a more accurate restoration — as well as time and money savings.

If you’re still within the learning curve in terms of capturing perfect digital scans, don’t worry — you’re not alone! According to the Centralized Digital Order Processing (CDOP) team at Glidewell, which handles all incoming digital impressions from doctors, there are three mistakes that most frequently cause issues with digital impressions and lead to delays and the need for retakes.

The good news is that it’s easy to correct once you know what to watch for. Read on for the list of the top three, and learn how you can keep these errors from happening. Before you know it, digital impressions — a key building block of digital dentistry — will be routine.

This one wins the award for “occurs most often” by a landslide. Achieving angles with an intraoral scanner wand can sometimes be difficult, and any areas of the dentition not scanned fully will result in missing information and blank spots on the impression. It happens most often on the hard-to-capture surfaces of the mesial and distal teeth adjacent to the preparation.

When this happens, the lab will typically have to ask you for a new intraoral scan before they can get to work on the restoration. While submitting digital impressions to Glidewell is a simple task, calling in the patient for a second round of intraoral scanning is not, so it’s best to avoid this however you can.

Obtaining superb digital impressions takes time. The more you work with the intraoral scanner wand, the better you’ll be able to manipulate it in ways that are comfortable for both you and the patient, while still capturing the information you need.

Below are a few checkpoints you should keep in mind when performing a digital scan. These will be useful in ensuring that you’re covering all of the areas you need to, and before long it’ll become second nature to do them.

• Visually inspect your results. Look at the screen as you work on areas where information is missing. Many intraoral scanners will highlight these for you so that you can go back and rescan the spots you missed.
• When it comes to the dentition areas that are just plain difficult to scan — whether due to awkward locations, lack of light or some other reason — develop a repertoire of potential methods that can help you capture what you need. Creative lighting, particular hand positions, and special wand grips can all go into your toolbox and be applied as the situation warrants. Keep in mind that every patient’s mouth presents its own challenges, so the more useful moves you have up your sleeve, the better.
• Get comfortable with your intraoral scanner! Many scanner manufacturers provide advanced instructions on scanning techniques that can help you achieve greater levels of accuracy for your digital impressions. Keep in mind that Glidewell accepts digital impression submissions from any intraoral scanner on the market, so you’re free to work with the one you prefer and are the most familiar with using.

Distortion or missing information caused by moisture in a scan is caused by the reaction of the intraoral scanner to anything that reflects back on it, such as saliva or other fluids. The scanner can’t differentiate between that reflection and the rest of the image it’s capturing. Depending on the viscosity and amount of liquid, it will either warp or entirely blot out the dentition beneath it, leading to models that don’t reflect reality or are missing information.

As with many things, when it comes to taking clear digital impressions, preparation is the key. Taking the time to remove moisture completely from the area is essential to getting a full and accurate 3D model and saves you time in the long run by eliminating the need for rescans. The tips below may also help.

• Make sure the lens on the intraoral scanner wand is clean and dry, and keep the wand within easy reach.
• Suction excess saliva while air-drying the field. Have the patient keep their mouth open.
• Use cotton rolls to help absorb moisture in lingual vestibules during mandibular scans. Cotton against the buccal mucosa can help control moisture during all scans.
• Remove any retraction cord while the mouth is still hydrated before using gauze and an air-dry syringe to dry the area again.
• If the patient can tolerate it, and you have enough room, keep the saliva ejector in place while you scan.

Digital impressions of the buccal view are particularly prone to inaccuracy due to the cheeks and tongue. They’re also prone to errors caused by an abnormal bite.

Misaligned occlusion in a buccal scan can give you a digital impression that shows the bite being open or misaligned in a way that it isn’t in reality. It can also cause artifacts or distortions that interfere with the image by causing misshapen teeth or inaccurate alignment. These issues can’t always be seen during the scanning phase, and often not until the digital impression is completed. Luckily, there are a few things you can do to help minimize the chance of this misalignment.

• Work with the patient to establish an accurate, natural bite before you begin the scan, and only activate the intraoral scanner once the bite is in place and the wand is positioned on the buccal.
• Inspect your 3D model thoroughly from the buccal view to ensure the contact points and intercuspation match the patient’s true bite.
• Capture as much buccal data for the maxillary and mandibular scans as possible to give the software multiple data points for use in aligning the bite scan.

Once you’ve identified the areas where your digital impressions have fallen short of ideal in the past and where you might benefit the most from these tips, it’s simply a matter of practicing them consistently until they become a natural part of your workflow. At that point you’ll find yourself quickly rewarded with increased accuracy — not only in your digital impressions, but also in the final restorations that rely upon them. Once you reach that point, you’re well on par with the latest trends in dentistry and positioned for future success.

P.S. If you're ready to move beyond digital impressions and get started in the world of in-office crown milling with same-day delivery, check out the glidewell.io™ In-Office Solution. It works with any intraoral scanner and makes the digital workflow simple and affordable.