Panoramic Discrepancies on Atrophic Mandible Ridge

Panoramic radiographs are good for a general assessment of jaw bone size and teeth / anatomical structures. However, the inherent magnification and difficulty of placing the jaws inside the focal trough, together with lack of third dimension can produce significant problems in assessing bone morphology. The panoramic  image Figure 1 below of a 76 year old lady shows a moderately atrophic mandibular ridge  but there does appear to be bone above the mylohyoid ridge in the posterior regions. However, in Figure 2  the reformatted CBCT panoramic shows none on the left and  a little on the right.


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Tracing of the inferior alveolar nerve canal in figure 4 shows the mental foramen at the level of the alveolar ridge.


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In Figure 5  cross sections across the mandible show the left mental foramen opening onto the ridge crest and a lingual knife edge ridge running from the mental

foramen region posteriorly. A similar appearance was found on the right side. None of this was apparent from the panoramic image although an experienced

clinician might be suspicious of the apparent panoramic ridge height .

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If you are planning implants cross sectional CBCT should always be performed after your initial pan assessment.



Dr Douglas K Benn BDS, M Phil, DDS, PhD, Diplomate of Dental Radiology (Royal College of Radiologists, England)
Professor of Oral and Maxillofacial Radiology
Creighton University School of Dentistry
Boyne room 207
2802 Webster Street • Omaha NE • 68178
Tel: 402-280-5025

American Academy of Dental Group Practice Event

Our CEO, Bret E. Royal, will be attending the 2016 American Academy of Dental Group Practice Event, taking place Thursday, February 3rd to Saturday, February 6th in Las Vegas, Nevada!

Take a moment to stop by the Implant Concierge booth, #528, and say hi to Bret! He will be there to answer any questions and looks forward to meeting some of our fellow doctors, and of course our potential new doctors!

Implant Concierge hopes to see you there. Have a great meeting!

For more information, please visit:

How To Read A CAT Scan

Quiet often, I am asked by dentists if they should get a Board Certified Radiology Interpretation on every CBCT scan.  Since I am not a lawyer, a dentist or an expert, I really can’t answer that question.  However, I always mention to a dentist that if they do not feel comfortable reading a CBCT scan, then it only seems logical that they should get an expert to review their CBCT scan.  With that being said, less than 10% of all CBCT scans acquired at our imaging centers and new cases started at order an interpretation.

I am surprised by this number, but also thankful because honestly, there aren’t enough radiologist to handle the workload if EVERY CBCT scan taken required a radiology interpretation!  The wait for an interpretation would be months!!  It is common for dentists to provide their own general review and if they see something that catches their eye, then they will order an interpretation.  Of course then, the next question is, “Is there a recommended process or official manner to read a CBCT scan?

To answer this question, Dr. Douglas Benn, one of our radiology partners and XXXXX at Creighton University has created this outline to help a dentist review their own CBCT.

Thank you Dr. Benn!


“A structured approach is required as there is a huge amount of anatomy contained within the scanned volume and unless a careful systematic approach is used then it is likely that you will miss something. My advice is:

  1. Review the clinical history, medical history, chief complaints. Know which teeth have been removed in the last few months to explain areas of bone loss with healing/ disrupted bone. Know if bone grafts are present and date of surgery.
  2. Review the axial slices starting with the anterior superior region (Frontal sinus), move down through the jaws and anterior face until you reach the cervical region. Then concentrate on the airway and spine and move up to the cranium. In this way you will cover the whole region. DO NOT THINK ABOUT THE CHIEF COMPLAINT  as this will bias you away from looking at all  the other areas.
  3. Now read the coronal slices from front to back and come back to the mental region.
  4. Lastly sagittal slices from right to left.
  5. Create a panoramic tomograph view and count how many teeth are missing.
  6. Adjust the field of view so you are only looking at the maxilla and in panoramic cross section work from right to left. Carefully examine all apices for widening of PLS, enlargement of the nasopalatine canal and presence of maxillary sinus bony septa as these should be avoided when performing sinus lifts.
  7. Adjust the field of view so you are only looking at the mandible and in panoramic cross section work from left to right. If implants or removal of third molars are planned, trace the inferior alveolar canals. Again check apical areas. In the midline search for the lingual canal if anterior implants are planned to avoid cutting these vessels. A simple arrow can be used to note the position of the canals.
  8. Lastly examine the region/s of the chief complaint/s and note abnormalities.
  9. Allow plenty of time. An average adult 40 years of age with most of their teeth and 2-3 root canals will take at least 20 minutes including make copies of selected slices of interest. A patient with large restorations and multiple root treatments (5+) is likely to take at least 40 minutes as the probability of apical pathology is high.

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The time spent will reward you handsomely as your treatment planning will be more thorough and you will avoid pitfalls of providing implants next to diseased teeth.”

Dr. Douglas K Benn DDS PhD, Diploma in Dental Radiology (Royal College of Radiologists, England)

Oral and Maxillofacial Radiologist
3610 Leavenworth Court
Nebraska 68105