National Dentex Labs Teaches Dental Teams How to Obtain the Best Digital Impressions

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How Kelly Bevington, NDX Director of Intraoral Technology and National Trainer and her team use their clinical experience to support and educate group dental offices so they can get the most from their intraoral scanners.

National Dentex (NDX) supports its DSO partners by offering complimentary digital intraoral scanning training. GDN spoke with Kelly Bevington, RDA, EFDA, the NDX Director of Intraoral Technology and National Trainer. She leads the NDX Clinical IOS Training Team that has clinically trained more than 10,000 dentists and their team members. The NDX training team visits practices and teaches them how to properly use intraoral scanning devices to obtain the best digital impression images to help ensure accurate restorations.

GDN: What is different about NDX’s intraoral scanning training?

Kelly: One thing I’m extremely proud of is that all the trainers at NDX are clinical dental professionals. We’re either registered dental assistants, certified dental assistants, internationally trained dentists or registered dental hygienists. That’s unique in the industry and a key differentiator for us. When you have worked with patients in the clinical setting, you understand proper ergonomics, the importance and techniques of tissue isolation and keeping the oral cavity dry, how to expose margins on crown preps, and how to identify and scan the appropriate anatomical landmarks. We provide DSO offices with “over-the-shoulder” coaching, and we work with clinicians, dental assistants, and hygienists, so they are able to capture the best digital impression or intraoral scan (IOS) possible, regardless of the system or software they use. Our team is continuously trained on all the scanner systems and each of their latest versions.

GDN: Let’s review the benefits of digital intraoral scanning.

Kelly: For most offices, the benefits of scanning are:

  • Increased accuracy
  • Shortened insertion time for the prosthetic device
  • Lower overhead
  • Practice efficiency

GDN: What are the typical issues you see with restorations coming back for a remake?

Kelly: By far, the greatest reason is the margin not being adequately exposed and captured. This means the laboratory can’t see the line to where they will design the crown. That is often a result of improper isolation technique, not keeping the oral cavity dry or not using appropriate gingival retraction techniques. We see these issues with IOS impressions and polyvinyl siloxane (PVS). With PVS impressions, some material actually flows into the sulcus, which then allows gingival tissue to expand and expose the margin. Dentists use many different retraction techniques, from retraction cord to retraction paste to lasers. We train them and their staff on how to be successful using their preferred approach for taking IOS impressions.

GDN: How do people decide what type of scanner to purchase?

Kelly: There are a lot of variables involved in that process. The things they should consider are:

  • Do they offer Invisalign to their patients?
  • What types of restorations are they providing most often?
  • What do they want to use the scanner for? Full arch scans, wellness scans or for hygienists to provide education?
  • Do they focus predominantly on implants, incorporate cone beam and CBCT scans or will they use the scanner for everyday crowns and bridges?

It also depends on the size of their office and what type of space they have. Some of these machines are substantially larger than others, so it’s important to consider the operatory dimensions and how they will wheel it through their office and comfortably and ergonomically satisfy the needs within the operatory.

Each IOS has a different space requirement—some come on wheeled carts, others use laptops and some wands are attached to a dental chair mount. Which system will fit best in your environment? When investigating the wired laptop, ensure that the wand cord is long enough to reach the patient when placed on a countertop. Envision the scanner in your operatory and its accessibility to electric outlets, the dental chair, air/water and evacuation.

Another thing to consider is file management. How will they use these files in the future? Are they going to scan and send them directly to a laboratory? Do they intend to do some in-office printing or milling? If they choose to do in-office printing of nightguards, bruxism appliances or surgical guides, that doesn’t mean they will not use a dental lab for crowns and bridges and so forth.

GDN: How else do you advise clinicians to evaluate IOS features and tools?

Kelly: They need a scanner to address their needs. Some scanners can detect caries. Others can integrate seamlessly with existing practice management software so they can have paperless records, confirm when a case has been accepted or sent out to a laboratory and keep all their RX information within the patient chart versus on the scanner or a cloud-based system.

Another consideration is patient communication. Some scanners have wonderful patient education software and communication capabilities.

I also recommend that practices schedule several IOS system demonstrations. I think evaluating the top 3-5 systems is essential when choosing the right scanner for their needs. It is important to physically hold the different scanning wands to assess ergonomics and comfort as they come in various shapes, weights and sizes.

GDN: What are some other considerations?

Kelly:  I think it’s important for people to understand the different IOS file types. The most common is the STL file, and you want to ensure your device has the capability to create them because that is what gets sent to the lab with your RX form.

Also, ask if the scanner takes high-definition (HD) photos, which is a very nice feature to have. With HD, the scan is more like a video. The video data is stitched together to generate a model. An HD photo allows you to zoom in, magnify a particular area and take a snapshot.

The HD photo feature is commonly used when restoring an implant or a general crown prep. It gives the laboratory a magnified HD image of the area they are designing a crown for.

GDN: What are the most common errors you see on the lab side?

Kelly: One of the most common is inaccurate bite registration. Typically, when a crown prep is done, the patient is lying down in the chair when they’re asked to bite down normally. The doctor takes a scan and assumes it is accurate because the data points on the maxillary and mandibular arch merge. Reviewing that merged image and confirming that the image on the screen is indeed what the patient is presenting in the chair is critical.

I recommend sitting the patient up and asking them to open and close two or three times to loosen up the condyles, then taking the bite registration. Its accuracy will increase dramatically. It is also helpful to take the bite-registration image before anesthesia. The dental assistant can take the maxillary, mandibular and bite registration scans before or immediately after the dentist anesthetizes the patient. The accuracy of the bite registration is often better before the patient is fully numb.

GDN: Anatomically, what part of the dentition is the best area to begin a scan?

Kelly: Always position the wand in the patient’s mouth before you turn it on and always start on an occlusal surface, preferably on a molar because it has the greatest points of data for that initial capture and will allow for much faster stitching and creation of the digital model than if you start on a lingual or buccal surface.

GDN: How long does creating a digital intraoral impression typically take?

Kelly: Once proficient, a single-unit crown-prep scan can take only 3-5 minutes, which is probably the most common scan we receive. It takes 3 minutes for a quadrant and upper/lower bite registration and closer to 5 minutes for a full-arch scan.

If the patient is being scanned for aligners, that requires acquiring data from every single surface of the patient’s dentition and 2-4 millimeters of gingival soft tissue, buccally and lingually. That would also be the protocol for sending a scan to NDX for a nightguard, a partial or restorations along that line.

GDN: What’s involved in an NDX scanning training session?

Kelly: That depends on how many people we will be instructing. I start with a 40-minute overview of the device, evaluate some of their past scans and ask them about a case that did not go well. We look at the scans and see what could have been done differently to accomplish a better result.

Then, we go over tips for using the scanner. I take a typodont with the maxillary arch modified for demonstrating a partial and the mandibular arch for an implant crown, a single-unit crown and a bridge. I use a brace to attach the typodont to the operatory chair so we can tilt it back and forth and into different positions to demonstrate proper ergonomics.

We show the staff how to hold the wand, position themselves to the patient and how to look back and forth from the patient’s mouth to the screen, teaching hand-eye-screen coordination while using the technology. We ask them to have at least three separate patient scans scheduled, and we stay with them during the scanning appointment to ensure that they are able to incorporate the new skills we just taught them. We provide over-the-shoulder coaching or jump in and demonstrate how to take the scan while everybody is present. We consider that the optimal way to do the training.

About Kelly Bevington

Kelly Bevington, RDA, EFDA, began her career over 20 years ago as an RDA EFDA, graduating from Bryman College. She has a comprehensive knowledge of dentistry and the dental laboratory industry. Kelly has been professionally trained on most major devices and can provide expert chairside coaching. She manages the NDX Clinical IOS Training Team and has clinically trained more than 1,000 dentists and their teams. Kelly enjoys sharing her knowledge by presenting webinars and regularly contributes to dental publications.

National Dentex Labs

National Dentex Labs (NDX) is a leading provider of dental prosthetics and products using the most advanced restorative techniques and technologies. NDX offers dentures, crowns & bridges, implant restorations, surgical guides and appliances, including orthodontics, migraine therapy, and sleep apnea products. Since 2015, NDX has aggressively expanded its national footprint to meet the demands of a rapidly changing marketplace and deliver best-in-class restorative solutions to dentists, specialists, and DSOs throughout North America. With a network of 55 full-service labs across the United States, NDX is committed to providing top-quality products and highly personalized service.