It’s All About That Image! Isolation Techniques For My Cerec Assistants, Part I

In the state of WA, dental assistants can image for crowns! That means you can take a “final impression” and I know, you may be thinking, “big deal”, right? Well, when you think about it, it actually is a pretty big deal. I mean come on assistants… We are trusted with the outcome of our patients restorations! That’s why it’s imperative we know what we’re doing, and we take it seriously. There are a few things that go into capturing a nice crisp image including, isolation, technique, and knowing what to look for. Here, you will find my process for making sure I get the best possible image, every time.


So, as I’m sure all my clinical peeps already know, when preparing the tooth for an impression (digital or traditional), isolating the tooth is a key component. Most of us probably use cord with a hemostatic agent and “maybe” half the time that works great, but it’s those patients with uncontrollable heme and tissue that can give us a challenge. I’m sure there are many of you assistants that have techniques that work for you, and that’s great! I’d love to here your tips and tricks for imaging, either here, on my blog or my Facebook page,

The most important thing for assistants starting out with Cerec, is knowing when you got the image. This is not something you can overlook in the slightest because, it directly effects the outcome of your crown. You can’t have a single spot on the margin that looks suspicious. Any area where the heme, cord, or tissue is questionable needs to be re-isolated and re-imaged. That being said, I’d like to share some tips that have helped me be efficient with isolating and imaging for crowns.

You usually have a good idea of what you’re dealing with when it comes to the tissue, once Dr. gets into his prepping. So, start by paying attention to the tissue and devising a game plan, that way you can have an idea of what you will want and grab anything extra you may need. I will always pack at least one size 00 cord. If i’m still seeing a lot of tissue near the margin I will then pack another cord usually size 0, but I will occasionally need size 1, right over the initial cord (size 1 for deeper gingival sulcus). This is to widen the space between the crown margin and the gingival margin, and will need to be pulled before taking the image (if the heme is under control, I will sometimes pull both cords for a more clear image, especially in the 4.5 software). The idea is to pull the tissue away long enough to leave a 5 minute working time once you pull the cord out. You are on a time crunch to get the image before the tissue begins to sneak back up to that margin, or it’s covered in heme. The only time I would recommend leaving the second cord in for the image, is if you are able to see the margin sitting higher than the cord you packed and there is no tissue touching any part of it. These are the patients with a deeper gingival sulcus. If you pack the second cord and you’re still seeing some heme or questionable areas, you can then start by using a micro brush with your hemostatic agent to help clear up those small problem areas. If I have more than a couple of those feisty areas, I will sometimes have the patient bite on a folded up 2 x 2 after micro brushing. This helps a ton, because the prep is dry and often ready to image when you take the 2 x 2 out. In extreme cases, where there is a ton of heme and tissue, I will pack my cord, then use a product from 3M called, Retraction Capsule. Click here for the product picture and video. This product works well because the tip is long and narrow and reaches under the tissue when dispensing. This acts as a hemostatic agent as well as cord. Now, I don’t use this all the time because for one, cost, and two, it doesn’t keep the tissue away like cord does, on it’s own. When I do use the Retraction Capsule, it’s almost always after packing my first cord and getting a feel for what I’m working with.

Another product I have used in more difficult situations is Epi-Pellets. These are more of a last resort for me because they are time consuming. The longer they sit there, the more effective they are. The Retraction Capsule sits for 2-3 minutes, is rinsed thoroughly, then it’s ready to go.

By gauging the prep and surrounding tissue, you should be able to quickly make a decision on which route to take and what you will need to grab.

A quick overview goes like this: if you’re dealing with more of a tissue problem and you’re not seeing a ton of heme, then you can quickly decide you’re going to pack two cords and that should take care of it. If you are more worried about controlling the heme, you can pull out you Retraction Capsule and have it ready. Once you find what works best for you in those different situations, you will become efficient no matter what the case may be. It’s about being able to plan ahead for the worst and tackling the problem right off the bat. You know we’ve all been there: We try the easiest way first, hoping that you can somehow make it work and when it doesn’t, you’re starting over, waiting for images to load, going back to acquisition phase and cutting stuff out. It’s all very time consuming when you could have started tackling the problem from the get go.

A great image is considered a great image when the prep and margins are crisp, clear and without any questionable areas of tissue, heme, or cord (or anything for that matter). You can design a beautiful crown, but you won’t have a quality restoration without a crisp image! Your isolation is key to a great image, which is imperative to produce a quality restoration that’s sealed well and lasts the patient many years.

As assistants, in the State of WA, we are allowed to take the images for crowns, bridges, and implant crowns (which are final impressions). That means that we are trusted to produce a quality restoration for patients, and sometimes a failed restoration leads back to those small details that we were trusted with. Paying attention to detail is important when getting an image, designing a crown or implants, and stain and glaze. This leads me to my next tip for Assistants learning CAD/CAM.

Know What You’re Looking For

Checking the margin can be a stressful task. Remember, that the image of the margin can make or break your restoration. One little piece of cord over the margin and you’re back to the isolation step.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s