Most Common Errors with the Dual Scan Protocol

In a previous post, we detailed the protocols to implement the “Dual Scan Protocol” (DSP) for fully edentulous cases. There are many benefits to using the DSP such as saving costs from having to duplicate the denture with a radio opaque material, the amount of time and the accuracy of a CAD/CAM surgical guide when the DSP is used correctly.

While the benefits are numerous and substantial, unfortunately, the DSP is by far the most widely rejected and trouble-some CBCT scan protocol for Implant Concierge referring dentists. Let’s spend some time reviewing the most common errors that we frequently see, and how it affects the accuracy and fabrication of a Fully Edentulous CAD/CAM mucosa borne surgical guide. Our goal by listing these common errors is to help our customers avoid these errors and help keep your Implant Concierge Guided Surgical cases stay on track and on time while minimizing unnecessary radiation exposure to your patients due to re-scans.




 Denture has a “soft reline”.

If the patient’s denture does not fit well without adhesive or the soft-liner, then the surgical guide will not either.  The denture’s hard surface (hardliner) defines the soft tissue dimensions. A soft-reline denture does not provide the required information and will result in a rejected CBCT DSP scan or worse, will result in a poor fitting surgical guide and if used, inaccurate final implant position.

    dent with soft reline

 The CBCT scan with the denture presents “black air space” between the patient’s soft tissue and the denture.

Black space is a true indicator of either an ill-fitting denture or soft-reline material or both.  This is not acceptable and the CBCT scan will be rejected.


 den ill fitting 1den ill fitting 2

 Radiographic x-ray markers not positioned correctly.

Use six to eight, 1.0mm x-ray markers, randomly positioned in the “pink”

 Mandl Denture Only Front w background on sponge (00000002)Mandl Denture Only Linglual on w background on sponge (00000002)

 Denture is cut off in the scan

The entire denture must be captured.  Before releasing patient, ensure that the entire denture is captured in both CBCT scans.

 den cut off

 Denture is touching  a hard-surface or CBCT platform

Denture should not touch any other radiopaque material or hard surface, such as the CBCT platform.


Position denture on a 1” – 2” foam block or magic eraser so that denture appears to be “floating”.


 den on platflorm

 Metal present in denture [mesh repair]

Radio opaque material other than x-ray markers present potential challenges.  If metal support or mesh interferes with intaglio surface or creates excessive scatter, CBCT might be rejected.  Locator housings might cause problems, but not always.  This is determined by a case by case basis.  To be safe, duplicate denture in clear acrylic and add x-ray markers!

 denture with mesh

Markers are moved between scanning the patient with the denture and scanning the denture solo.


Take CBCT of denture only first, then take second CBCT of patient wearing denture.  Do not move the x-ray markers between scans, otherwise the merge of DICOM #1 and DICOM #2 will be unsuccessful.

  Using “flat” markers

Flat markers are common when using gutta percha as the radiopaque markers.  They should be rolled into a ball and adhered to the denture.  If they are smashed flat, we cannot see a difference in what is a marker and what is the denture.

 den with flat mark


If you have any questions, comments, or concerns, please let us know at or by calling us at 866-977-2228. You may also tweet us at @CBCTmade easy, or ask us on Facebook!