Category: Digital Impressions

Same visit restorations are a great way to measure accuracy of an iOS and cad software and milling machines 

One thing that I highly recommend is to take the bite before imaging the prep itself. It forces you to check for clearance and to keep reducing until you have the appropriate space for a ceramic restoration

You have to be comfortable with different workflows you may be accustomed to 

Emax Try- in before bonding with NX3 resin cement

Immediate post op

Don’t be mislead; it is much easier to scan the upper edentulous jaw than the lower, as you don’t have to deal with the tongue or saliva. With the Medit i500 we have a feature called the model display mode, where you can see how the meshwork is being formed by turning red areas to green. When scanning, you can image at the rate of “red colors turning green” so you can produce global accuracy across the arch without distortion or double images forming like you see with all intra oral scanners when they try and scan edentulous ridges on a flat plane

You can download the meshwork for this case by clicking here (Note that the gold caps were omitted on purpose)

The following case is a 4 unit splinted bridge where the upper central incisors where root canal treated. The laterals remained vital after trauma to the upper maxilla fracture a pre-existing bridge. In this single appointment procedure, the case was set up by imaging the pre-existing temporaries, the opposing and the bite.

After the preparation were made, the tissue was retracted and hemostasis was achieved. The preps were imaged in HD mode with the Medit i500 intra-oral scanner. The restorations were designed in exocad and the final prosthesis was milled with the Z4 VHF Milling Machine. A size 40 block was used to mill the splinted units of eMax.

The fixed bridge was seated with NX3 resin cement and the excess was removed. Cord, packed in the sulcus, allowed for easy identification of the margins in the design step and aided in cement clean up. The patient will return for post op photos once the tissue has healed. The following video depict the steps the milling machine goes through as it carves out the four unit bridge, starting with the 2.4 mm drill, then the 1 mm drill, and the 0.6 diameter drill. Milling time was under 40 minutes

Look at that contact area! A dentist’s and lab tech’s dream, but you still get some crowns that are way too tight and you adjust like crazy until it seats and if you were too aggressive, you likely blew right through the contact. Here is what is happening:

When you image what is happening is that you are imaging below the height of contours of the adjacent teeth / contacts.  A designer just sees a big contact area with lots of colors and s/he is happy, not realizing that they actually made contact with material BELOW the height of contour of the adjacent teeth. This is a VERY common error.  It will sound strange, but if you are an advanced user, consider NOT taking scans below the HOC and let the software drop a straight wall down to the gumline and your seat issues will disappear!  You can also recognize this issue and communicate it to the lab so they can address it

This a case that was done in a single appointment, where the second molar was restored with a class 2 composite restoration and the first molar was replaced using the copy mode in exocad. An initial scan was taken copying capturing the outline form of the pre-existing restoration, the crown was then removed, the tissue was retracted and the preparation was modified

After the decay was removed the Medit i500 was used to capture the prep and the restoration was designed in our CAD software. The eMax restoration was milled and crystallized and then delivered with NX3 resin cement

This restoration was milled in the regular mode without using the 060 drill. This speeds up milling but does not provide for detailed anatomy, which you can accentuate with a handpiece. It is your decision to select fine mode, regular, or fast mode.

Immediate post-op bitewing X-ray was taken to verify fit and to remove any excess resin that may have been left behind

Since July, we have imaged and milled many restorations with at least 4 different milling machines, including lab fabricated restorations. The margins and fit have been impeccable even with my terrible preps :). I love seeing the post op bitewings and the adaptation of the restorations. One thing I love having control over is the spacer settings; both the amount of space and also the distance I want the gap to end from my margins.

The following case is a lower first molar with the distobuccal cusp fractured and recurrent decay underneath the pre-existing composite restoration, warranting full cuspal coverage. The case was managed with the CAD-Ray workflow, where the medit software is launched and all the imaging is done in that platform.

Directly from meditlink, exocad software is launched and the margins are placed. Once the restoration designed, it nested in the block and sent off to the milling machine. The total time from final design to end of mill was about 18 minutes, and the last 4 or so minutes, the milling machine refined the sprue size and location. One can easily stop the milling process and remove the sprue manually.

Once the restoration was assessed for fit and proper contours, it was chrystalized and then bonded in with Kerr NX3 material. A final post op bitewing was taken to assess if any excess cement was left behind.

Time Stamps:

This video is sped up at some points, but from the time the design was finished and it was sent to production, it tool less than 90 seconds for the milling machine to start milling. It took a total of 9 minutes and 20 seconds from the time the first water is sprayed to the time the water stops.

The Meditlink software allows you to log in as a clinician or a laboratory. There are quite a few benefits to logging in as a lab, one of them is to have control over the whole process from imaging to design to fabrication

Here, we demonstrate how the case is set up in the job definition. We have linked the exocad CS CADapp as the design software of choice. You have many other options including manually exporting the models.

Once you define the job, you can directly launch the Medit scanner and start imaging. Once you are finished with imaging, you can start marking margins and complete the design of the restoration in the CAD software.

Once designed completely, you have a number of ways to submit it tofabrication. One big advantage here is how you can start milling as soon the calculations start, with the VHF Z4 milling machine. As opposed to milling machines that must have the calculation completed before they start milling, which oftentimes puts the procedure outside the realm of single visit dentistry

Imaging highly reflective surfaces can be challenging. In this particular situation, every tooth had either a pfm or a gold crown restoration. The video playback feature of the medit software allows you to see exactly how these areas are managed and captured. in the live preview box in the lower right corner, you can see the purple silhouette which shows areas that cannot be seen. Just angle the camera and moving its focal length and angulation allows all the areas to be captured. Not retraction besides a mirror was used. No isolation, air, or suction was used. Both arches were captured for an obstructive sleep apnea device with the Medit i500

Scanning highly reflective surfaces can be a challenge with every intra-oral scanner. Here’s a pointer that can help: don’t start by trying to scan the metal or highly reflective surface. Get your purchase point on material that is easy to scan, like gum tissue or tooth structure. Once the model starts to form, you can then build on your desired material.

In this example, we are scanning a metal framework for a hybrid. Notice how the scanner does not recognize the metal at first, until it starts to image the thumb holding it. Once you start building the metal model and then remove the thumb and image over that area, the fingers are removed from the equation