How to use Interproximal Scan

Table of Contents

Some people ask me that they hear about Interproximal Scan a lot, but what is the function, and others ask me that they know Interproximal
Scan is good, but how does it work. 
Today, let’s take a look at what Interproximal Scan is and how it can be used.

Example of when interproximal scanning is useful: scanning a solid model without pin work

To learn more about Interproximal Scan, I prepare a solid model. Most labs do pin work and scan abutments separately, but some labs don’t do pin work and just scan solid models. In that case, Interproximal Scan is very useful.

Then, I will show you how the data are different between the cases with Interproximal Scan and without Interproximal Scan.

How to work with a solid model using interproximal scan

First, I’ll create a project in the exocad window. Make the exocad project called Interproximal Scan Test. When you run ScanApp for the first time, the scan setting window appears.

In the case of a pin model, there is no option to scan interproximal areas because abutments can be separated and scanned. The interproximal scan option is appeared only when a solid model is selected. I have to choose whether to scan only the buccal or the lingual side as well. I will proceed to scan with the lingual side.

First, I’ll scan a base model. If you look at the area on the interproximal side, the unscanned part like the image below appears in black holes. Even if you do an additional scan, this part is very tricky to scan.

In this case, it is much better to use the interproximal scan function instead of trying additional scans.

Place the model upright like this for Interproximal Scan.

The second step is scanning the lingual side. Attach the model using gum and place the labial side of the anterior teeth towards the bottom of the scanner.

Interproximal Scan is finished. There is no need to perform additional scans even though there are unscanned areas. It is because the data will be combined by matching the scanned data.

First, I’ll delete the unnecessary part. Let’s match the data like the image below.

When you look at the abutment after matching, every part is scanned precisely without any unscanned parts. All the margins are scanned cleanly.

I will delete the unnecessary part and proceed with the build. 

The difference between hole filling and Interproximal Scan

Maybe some of you have questions like this. My scanner can scan interproximal area well even without using Interproximal Scan. I’d like to say that it’s misunderstanding. It’s because the holes are automatically filled during the build process. Then, even if it wasn’t scanned, it looks like it’s been scanned. The problem is that you can’t get the real data. When a hole is filled, the program grasps what the scan data look like around the hole, then it fills the hole by prediction. Therefore, the hole is not the exact data. If you make a prosthesis over it, it doesn’t fit well.

After the build is complete, you can see the margins that have been reproduced very precisely.

Until now, we learned how to use Interproximal Scan works with solid models.


How Interproximal Scan can be applied to the partial model

Lately, many people are working on partial frames with CAD. Therefore, Interproximal Scan is gaining popularity. In the case of a partial frame, a clasp of the partial frame is attached to the interproximal area. We use the clasp’s tip to get retention. However, since the interproximal part is not well scanned, the end of the clasp is not properly attached. Thus, the retention power is lost, or rather more retention power is gained. Let’s take a look at how Interproximal Scan can be applied to the partial model.

Comparison between Interproximal Scan and the model without Interproximal Scan by data matching

Create a project at exocad. For a more reliable comparison, I will compare the model with Interproximal Scan and the model without Interproximal Scan by matching these data. Now, let’s first scan without selecting the Interproximal Scan option. If you scan without Interproximal Scan, most results would be like the image above. It doesn’t scan well, but the holes are automatically filled after build, so it looks like the scan is well done. I’ll save this data.

And for the data to be scanned this time, I will apply Interproximal Scan. If Interproximal Scan is complete, save this data as well. Now, let’s open exocad and compare the difference between these data.

This model is scanned without Interproximal Scan. Let’s load the model with Interproximal Scan applied as gingiva. I will load the data and match by three points matching. 

You can see the big difference between the two data, depending on whether you’ve done Interproximal Scan or not. Let’s take a cross-sectional view and see how different these data are.

If you look at the graph above, you can find out that the actual data is deep inside, but the hole-filled data is blunt. The clasp tip has to come into the end and hook the tooth, but if the class tip doesn’t come into the end and can’t hook it, you can’t get the retention.

So far, we’ve seen how Interproximal Scan is applied to the partial model. If you are worried that the clasp tip’s fit is not good, I’d recommend applying Interproximal Scan. If you feel that the crown does not fit on a solid model, I’d recommend trying Interproximal Scan as well.

Thank you for reading my lecture, I will be back with another good contents later.


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