What are the 4 Steps of Performing a Dual Scan for Single Arch and Double Arch Cases?

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A scan appliance for a fully edentulous is generally the patient’s existing denture. Now there are some rules about that. You want the denture to fit, in other words, you want the denture to seat with no rock, a nice positive seat, and you want it to have good occlusion. If it doesn’t have good occlusion, equilibrate. And if it doesn’t fit, well do a hard reline, never a soft reline. If you do a soft, then the soft will show up in the cone beam as a void and we can’t tell that the denture is fully seated. So do a hard reline or if you have blue mousse, you can load this with blue mousse and fully seat it. Put the patient in occlusion and then take it back out of the mouth and you’ll put markers on it. We’ll talk about the markers in just a second, but the most important part is the denture fits the blue mousse will make it fit.

The hard reline will make it fit. And you have an intimate contact between the tissue, between the tissue and between the denture when you’re doing your dual scan. If you don’t have a denture, then do the normal customary workups to get a denture bite block set up. Try in and finish the denture because if you’re doing a case like we normally do then you’ll want to back up denture anyway, and that serves its purpose. The next step with the denture, let’s say your denture fits and it has good occlusion, then the next step is to put markers on it. With all, with all dual scans, the scan appliance has to have markers and it has to have four to six markers, preferably six if you have them. You can use either a gutta perca, uh, like a number eight round bur and just buried about a millimeter deep randomly in the pink.

Or you can purchase, uh, sure marks from a company called Sure Mark, or we sell them as well. They are clear radiopaque markers and they come on stickers and you’ll just peel the sticker off and you’ll place them randomly on the pink surface of the denture. On the labial. You can put ’em on the tongue side if, if you want to, if for some reason it’s not much flange, you could even put ’em in the tissue area, but you wouldn’t want to put ’em on the intaglio because that’ll hold the denture up. So place six markers and then your denture is ready to scan. Many of the patients that we work on are double edentulous, upper denture, lower denture, and on those cases we do something a little bit different. We will make both scan appliances or we use both dentures and in this case we use 12 markers, six on the upper, six on the lower, and we do a dual scan.

Actually that’s three scans. The first scan is with both dentures in the mouth in occlusion, which we’re gonna show. And then the second scan is of the appliances by themselves individually. When you take a CT scan for an edentulous, you always have the teeth together biting. You never put cotton rolls or a stick bite or the scan of the scan bite to separate the teeth. We want the denture to be loaded in full occlusion so that we can plan the case when we know that it’s contacting tissue in occlusion, that’s very important. So you’ll just have your patient enter the machine and put their chin on a chin rest. Different machines have different types of chin rests, but just have ’em put it on the chin rest, bite together. Make sure that you visually see that they are biting in their habitual denture bite.

They’re coming together. Hold on and take the CT. The second scan will be of the scan appliance alone. And maybe you’ll notice if you’re zoomed in on this, you’ll notice that there are markers on the scan appliance. Now these markers are the, in the same exact position as the original scan in the mouth. They have to be the same. If for some reason the patient left and came back because there was an error with scanning, redo the markers and redo both scans. If the appliance is sitting on plastic or the metal table, this becomes this, they will actually merge together and we can’t separate them. If you take a scan like this, the appliance will appear as if it’s floating in space when we’re planning the case and when we’re bringing the files in. So we will register the denture with the patient as a dual scan.

So you simply take this scan and you’ll export this file and you’ll export the one with the patient. You’ll send them separately. Name one patient, one appliance, zip the folders, and simply upload. And just like with the upper, you’ll have markers, six of them randomly placed around the denture and they are the exact same in the exact same position as they were in the mouth. If they change or deviate at all for some reason, you want to do both scans over again. So that is the second scan. You’ll export this one, you’ll export the upper, you’ll export them in the mouth and you’ll have three folders. Lower, upper, patient – name them such, zip them, and then send them off to the laboratory.


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