Analyzing the CBCT of a TMJ & Sleep Disordered Breathing Patient
This webinar took place on July 9, 2021, but you can still view the recording.
Dr. Tamimi earned her dental degree from King Saud University, Riyadh, Saudi Arabia in 1999. She trained at Harvard University and earned a doctorate of medical science (DMSc) and certificate of fellowship in Oral and Maxillofacial Radiology in 2005. She is board certified by the American Board of Oral and Maxillofacial Radiology (ABOMR). Dr. Tamimi is a co-author on “Diagnostic Imaging, Oral and Maxillofacial”, the lead author on “Specialty Imaging: Dental Implants”, and “Specialty Imaging: Temporomandibular joint”.
Chat comments to audience:
The main purpose of today's webinar is to teach objectivity in diagnosis. As much as we would like to discover findings that tell the story we want to hear, we have to keep an open mind to hear the story that is there and not the story that we want to see unfolding. This is a cornerstone in the art of diagnosis. I will touch upon this later during the Q&A.
While we have to look for instances that the TMD and sleep-disordered breathing symptoms and risk factors are linked, we also need to know when they are not and try to avoid the temptation to create linkages where there are none.
1.Is there an average airway measurement? Dr. Tamimi stated this airway was "narrow" but that is kind of subjective.
I measure the airway after this initial analysis. At this point I am collecting information about the morphology and the anatomy of the patient's craniofacial complex. It is important to realize that the measurements do not mean much without clinical correlation as there are multiple factors (postural and functional) that may narrow the airway during scan acquisition.
2. How old is this patient, gender?
This was a female in her 40s.
3. What causes septal spines?
Septal deviations and spurs can be developmental, traumatic, or functional. I see them often with maxillary asymmetries.
4. How clinically relevant is it to evaluate airway on cbct since it is so fluctuant?
Very. Airway analysis on CBCT is not just measurements of the oropharynx. It is a structural and morphological evaluation of the craniofacial complex to determine the areas of restriction and diagnose the cause of of the alteration of the jaws and growth deficit. It is a detailed and sequential evaluation of the patients anatomy that helps us diagnose why patients appear and function the way that they do.
5. I think it's important to look at the patients to see if photographs corroborate to the asymmetry you find on scan
Absolutely! Which is why I love receiving these clinical photographs and detailed history. Unfortunately I don't always get those so I do what I can with what I have. I will often create a surface rendering of the skin to see if there is a soft tissue compensation that masks the skeletal asymmetry. The asymmetry is not just about esthetics though, and we have to see if the bone tells us a story of altered function that is clinically relevant. With alteration of function comes an alteration of form.
6. Do you recommend taking these CBCT in MIP?
I do. This enables me to see what the condyles do in MIP
7. Do you have an airway measurement that you would say is somewhat normal? Up to what measurement mm2 do you suspect sleep disorder breathing is a concern?
These measurements don’t really mean much without clinical correlation. Below 120mm2 would be considered high risk, but really, you can have huge airways and increased collapsibility and sleep apnea and you can have small airways with good muscle tone and no sleep-apnea.
8. When should we be concerned with Concha Bullosa findings?
Large turbinates of any sort change the air flow. They are a risk factor for sleep-disordered breathing that should be put into consideration with the clinical presentation.
9. Could the morphology of the right condyle be an exostosis which can be exacerbated from bruxing?
Form follows function. The articular surface of the condyle responds to increased function by increasing surface area, by flattening and osteophyte formation.
10. Do you ever evaluate the swell body of the nasal septum and how often do you see posterior ponticle of the atlas (arcuate foramen)?
When I see a large one that is blocking the internal nasal valve I comment on it. With regards to arcuate foramen: The incidence is about 16.7%, but I don’t see these commonly.
11. I was told by a sleep physician that if the minimum cross-sectional area of the pharyngeal airway is less than 100 mm2, then they are at risk for OSA.
These measurements don’t really mean much without clinical correlation. Below 120 mm2 would be considered high risk, but really, you can have huge airways and increased collapsibility and sleep apnea and you can have small airways with good muscle tone and no sleep-apnea.
12. Does the course in Sep & Oct 2021 include info on TMJ and Airway?
Here is a link to both courses; https://www.beamreaders.com/courses. The Sept/Oct course does include 4.5 hours of TMJ & Airway information. The July/August course is more detailed, nine hours total. At the link I included here you can hit 'explore' and then 'download course overview to see the details.
13. Dr. Dania Tamimi, do you recommend a pathological reading of every CBCT scan that is taken in an office?
Someone has to read the scan, either the dentist or the radiologist. Reading radiographic material is a specialized dental procedure that requires extra education beyond that taught in dental school and passingly in conferences. It also takes time (30-60 minutes) to read a scan properly and to write a report.
14. What would your working diagnosis be for the nasopharyngeal mass continuous with the sphenoid sinus? Do you provide possible working diagnosis' for each of the common anomalies you find in your courses?
A benign soft tissue entity, most likely antral polyposis because it was not destroying or expanding the walls of the sinus, but had the appearance of worming its way through the drainage pathway. To review the common anomalies, it is better to book a private course with specifically this material prepared for you as it is a special interest area. The course goes through typical normal anatomy, which is a good place to start!
15. Can we request Dr. Tamimi to evaluate our CBCT submissions to BeamReaders?
You can certainly request this with your case submission Dr. Brawner! However due to her lecturing and travel schedule, Dr. Tamimi isn't really taking new clients. The turnaround can be long due to this. Happy to connect you with an OMR here that could turn your cases around in our typical 2-5 days!
16. I have questioned whether to take a screenshot of the pano before repositioning to image the joint. From what you are saying here we should start with getting the joints aligned?
We are not aligning to the joints. We are aligning to the external auditory canals.
17. Will the Sept/Oct course require a live participation? Would it be possible to gain access to a recording?
These sessions are not recorded, and so would require live (virtual) participation. Dr. Tamimi does these courses typically 2x per year and we can let you know about future courses too
18. Can you comment on the ideal position of the hyoid to the mandible?
The average is about 14mm inferior to the inferior border of the mandible, with men having a lower hyoid (up to 17mm).
19. How often do you see osteophytic lipping of the anterior bodies of the cervical vertebrae when there is nasal obstruction present?
I have honestly not made an association, but I will look from now on.
20. Will a hands on practice be given in September course?
There is the option to add on a private two hour session after the course in which you will be able to practice the practical component.
21. Would it be accurate to measure mandibular asymmetry in the 2D pano?
A 2D panoramic projection has too many source of error (magnification, distortion, superimposition.. etc) to be reliable for measurements.
22. What was in the sphenoid sinus?
A benign soft tissue entity, most likely antral polyposis because it was not destroying or expanding the walls of the sinus, but had the appearance of worming its way through the drainage pathway.
23. I have a child patient with hemifacial microsomia and in treatment with ALF therapy. How do you suggest to measure the changes periodically without exposing the child to radiation? Thanks you for your wonderful presentation!
I would ask an osteopath about this one. You could look into anthropologic points on 2D and 3D photographs, but this will require more training on your part to do accurately.
24. (Do you have a) recommendation for how to not freak patients out when recognizing abnormal anatomy?
Try this, “CBCT is a limited diagnostic tool that gives us very specific information. In order to determine if this finding is significant or not, I need to refer you to the appropriate specialist that can further assess this finding. That specialist may say that its nothing, or may require more tests. As a dentist, my expertise does not extend to this area.”
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