How are you taking impressions for crown and bridge in your dental practice?

 At the moment we are taking impressions two different ways. The traditional way is still valid and involves using elastomeric impression material, usually PVS type. Often this requires cord packing prior to taking the impression. If use properly it can take extremely accurate impressions . The models are poured up by the lab and mounted using a bite registration. The resulting dental restorations made on these models can fit extremely well. Some inaccuracies can result when the opposing models are mounted and can necessitate occlusal adjustments on the restorations before they are luted in the mouth.

We recently purchased a state of the art Trios 3D Scanner and my son has been using it extensively for taking full arch impressions of the mouth and opposing arch, even for single restorations. These scans, if done with appropriate care are extremely accurate. I believe their digital mountings are even more accurate than the 'old school' techniques that I use. We ask the lab to use their best 3d printer to print a hard uncut model and they use that to fit their milled crowns. 

Taking digital impressions can still necessitate packing cord to clearly expose preparation margins and crown preps should be a clean and smooth as possible, since scanners can only optically impress details that are visible to them. Saliva, blood and gingiva can introduce inaccuracies.

Preparations need to be as smooth and continuous as is possible and steps or sharp edges or undercuts can result in poorly fitting restorations. This is true for both types of impressions , but is especially true for preparations that are to be digitally scanned.

I look forward to using the scanner myself for my patients. It is much easier to use to help fabricate night guards and essex retainers and we even have used it to duplicate dentures that my patients are happy with but want an extra spare.



from Ask Dr. Spindel - http://lspindelnycdds.blogspot.com/2025/04/how-are-you-taking-impressions-for.html - http://lspindelnycdds.blogspot.com/

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