Risks of child CBCT revisited.
Last week’s blog post on the risks of chlld CBCT sparked many questions and controversy, particularly on social media, where I received considerable criticism for suggesting that we should not routinely use CBCT examinations on children. I wonder if my message was lost amid the substantial “white noise” surrounding this issue. Therefore, I have written a new post to outline what I believe are the main points regarding the routine use of CBCT for children.
I will start with the British Orthodontic Society Guidelines. Although they are getting rather old, their essential messages are still relevant.
British Orthodontic Society Guidelines
The general theme of the guidelines is set out in this statement.
“Before any radiographic examination, a clinical examination must be conducted to avoid unnecessary radiation exposure. To prevent radiographs from being taken simply because it is ‘routine’, the justification should conclude that the needed information is not available elsewhere and that radiography is the most suitable method for obtaining it.”
There is no safe dose for radiation exposure; radiation dose is accumulative. This is particularly important for child radiography.
What is the dose?
There is a surprising lack of knowledge about the dose from CBCT taken for orthodontic purposes. This is a rapidly evolving field, and I have taken this from the ADA recommendations on dental radiography.
| Type of examination | EFFECTIVE DOSE, AVERAGE OR RANGE,∗ μSv | AVERAGE BACKGROUND RADIATION EQUIVALENT, D† |
| Extra oral radiographs | ||
| Panoramic | 19.0-75.0 | 2-9 |
| Cephalometric | 2.0-10.0 | < 1-1.3 |
| Paediartic Cone-beam computed tomography | ||
| Small FOV | 7-521 | 1-61 |
| Medium or large FOV | 13-769 | 1.5-91 |
The most striking feature of this table is the wide range for CBCT doses. These were obtained from the paper by Ludlow in 2014.
To put a perspective on this information, people often quote the equivalence to natural background radiation.
- Natural background radiation: ~8–10 µSv/day.
- Depending on the settings, a CBCT scan can equal a few days to several months of background radiation.
- Panorex and cephalometric images roughly equal 1–3 days of background radiation.
One of the most frequent points raised by orthodontists justifying the routine use of CBCT is that the dose is the same as that for a cephalogram and panoramic examination. However, I cannot find any scientific publication that states this.
I have looked at the documentation for the Newtom, Morita Accuitomo 170 and Carestream CBCT machines but could not find any information on their effective doses for an “Orthodontic” CBCT. This was disappointing. There may be a lot of smoke and mirrors surrounding this critical issue. If I have missed something, can someone point me to the evidence supporting the claims about similar doses?
Is CBCT useful?
There is no doubt that we obtain great images with CBCT. However, limited research has been conducted into the utility of these images. The only papers that I have come across have suggested.
CBCT cannot be recommended for a valid and reliable comparison of airway dimensions for our patients.
CBCT images provided much additional information than conventional views, their use did not significantly impact the treatment decisions for impacted canines.
Therefore, there is a lack of evidence for the effect of CBCT on changing or reinforcing our clinical decisions. It still appears that we can get sufficient information for diagnosis from examining the patient and 2D radiographs.
ADA recommendations
The latest set of recommendations on dental CBCT are included in a recent set of guidelines produced by an expert panel from the ADA. These state:
- Exposure to any amount of ionizing radiation can increase the risk of adverse health effects.
- Dental imaging exposure levels are typically well below the threshold for harm. However, patients often undergo multiple radiographic examinations throughout their lives, and studies have shown that cumulative low-level radiation exposure may be associated with triggering oxidative stress or potentially inducing damage to cellular DNA or oral epithelium, thereby increasing the risk of carcinogenesis. In addition, the risk for children may be heightened due to longer cumulative exposure over their lifespans as well as their higher organ radiosensitivity.
- A CBCT examination should not be merely routine and should not be used for screening purposes.
- CBCT imaging should not be used routinely. CBCT examinations shall not be used as the primary or initial imaging modality when a lower-dose alternative is adequate for diagnosis and treatment planning.
Decisions
It is, of course, a personal decision for orthodontists to select the radiographs they deem most useful while ensuring the lowest level of radiation. However, we should not disregard guidelines merely because they do not align with our clinical experiences. If we do, we put our patients at risk. Furthermore, are we also risking ourselves? For instance, where would you stand if you performed a CBCT on an 8-year-old to assess the airway and, many years later, they developed cancer? What would your grounds for defence be?
Final comments
After reviewing much information and discussing child CBCT with maxillofacial radiologists, I would follow the ADA guidelines and not use CBCT routinely. I would stick with standard 2D views where indicated and only take CBCT views when I need them to investigate potential problems further.
Importantly, I don’t understand why some people reject the ADA guidelines and feel they know better than an expert panel. I, certainly, do not have the knowledge to disagree with these panels.
Let’s have a civilised chat about this.
Emeritus Professor of Orthodontics, University of Manchester, UK.
Congratulations! Even in adults, the guidelines should be the same. CBCT would not be a routine in orthodontic records.
the key word here is ROUTINE…I know of no one who takes routine CBCT on children…however only after doing a thorough and complete diagnosis can a decision be made and sometimes the decision is not to take a CBCT but on other occasions we decide to take a CBCT….and that makes in some cases all the difference…..after nearly 40 years I am seeing that 70-75% of my first consultations are retreatments…and almost always due to misdiagnosis…..diagnosis is the name of the game and sometimes CBCT helps
Kevin
well said – absolutely agree
Ross
Kevin,
I appreciate the post. A quick Google search revealed this handy PDF from Planmeca regarding the effective dose of their CBCT machines. Although it does not specifically call out “orthodontics,” the imaging profile used for an orthodontic exam is the “face” setting. https://www.planmeca.com/globalassets/planmeca/usaintranet/radiation/effective_doses_planmeca_xray_0413.pdf
Thanks this is useful. I have looked at this table and I cannot see a dose for a child. Unless, it is stated in the row “child skull”. This is 128 µSv. Unless I have missed something? Best wishes
I’m pleased to say that you are revisiting this issue and took the feedback you received seriously. I’m also pleased that you put in the ranges of effective dosage for CBCT imaging to prove the point that a full FOV CBCT image can be taken for LESS radiation than a panorex alone.
I’d also like to point out that your statement that “panorex and cephalometric images roughly equal 1–3 days of background radiation” has multiple flaws. Firstly, a panorex cannot equal 1 day of background radiation (8-10uSv), as the dosage at lowest end (per your numbers) = 19uSv. Additionally, the way you stated it makes it seem as if a pan and a ceph can be taken for 1 day of background. That is false.
Secondly, in the bullet point prior to that, you reference both the high and low ranges of the effective dose of CBCT when you state they can be “a few days to several months of background radiation.” Ironically, when referring to panorex and cephalometric images, you only cite the lowest end (1-3 days). To be fair and factual, you should state that the combined values of a pan/ceph can be as high as 10 days of background radiation.
For someone who is such a prolific writer and quite precise with their verbiage, I find such flagrant wordsmithing quite interesting. I sincerely hope the inaccuracy of your comments was merely an oversight and not intentionally meant to mislead the reader.
Lastly, I’ll repeat the question I asked you on social media but you neglected to answer. If we can take a full CBCT image on
a child (low-dose = 13uSv, per your numbers; 17uSv per Ludlow, AJODO 2013) for LESS radiation than a pan and ceph (total at lowest end = 21uSv, per your numbers), AND we know that we can get exponentially more diagnostic information from a 3D image (which is not disputable), what could possibly be the argument against the routine use of CBCT imaging for pediatric patients?
Thank you for your comments. The statements regarding dose equivalents were derived from multiple sources, including the International Atomic Energy Agency, which supports the accuracy of my remarks. Additionally, I believe you missed my point about the use of information from Cone Beam Computed Tomography (CBCT). There is limited research on this topic, and we should be cautious about assuming that high-quality images will automatically influence our treatment decisions.
Importantly, radiographic guidelines indicate that CBCT should not be used routinely. This fundamental information is crucial to consider, and it is the primary focus I aimed to convey in my blog post.
Not surprisingly, you continue to evade the question, which confirms that you cannot answer it. It also shows that you were likely trying ot decide the reader with the way you worded the bullet points. But nice job trying to deflect.
Also, are you really trying to make the argument that we need a study to say that a 2D pan/ceph allows you to see more diagnostic information than even a low-dose 3D image? I’d like to think you’re more intelligent than that.
Additionally, the “radiographic guidelines” you quote are irrelevant if they are not taking low-dose imaging into account.
Since you’re clearly either unwilling or unable to answer my previous question, let’s see if you can handle this one: Do you believe in ALARA principles?
I answered your question. Yes, I do believe in ALARA. I feel that you are getting too aggressive and rude. As I wrote in my blog post “let’s have a civil discussion. So this exchange stops now.
Looks like we typing the same viewpoint on comments simultaneously, Kevin!
You absolutely did not answer the question. You evaded it and gaslighted like you always do.
If you were the true academic you claim to be, you could take a little heat, Kevin. I thought you were tougher than that! Ironically, or not, you refused to answer the same question when asked by a colleague online. But for him the reason you gave to stopping the conversation was that he was a KOL for a company that had absolutely nothing to do w/CBCT whatsoever. I’m noticing a trend – when you can’t defend your position, you take your ball and go home. If you can’t take the heat, then don’t put these topics out there, my friend! After all, you’re the one who started the thread, not me!
Furthermore, and back to the topic at hand, if you believe in ALARA, then please explain how you defend taking a 2D image that delivers MORE radiation than a full FOV low-dose 3D image??? I’ll wait…
As for your comment that there is insufficient research on the benefits of 3D over 2D, do you feel 3D has any benefits over 2D when it comes to impactions? Or cleft-cranio patients? Or implants? Or surgery? If so, then you’re inherently stating that it has a value beyond what can be seen in 2D.
Please keep it civil. We’re supposed to be professional, so please let’s keep the language that way. Anyone who likes inflammatory or insulting comments should redirect to X 🙂
I am concerned that many CBCTs are taken on a first visit, without an adequate explanation to parents (oh, we just going to take some pictures) or a clinical evaluation first (for which you would lose your license to practice in much of Europe). Also most of us in practice are not using the newest and lowest exposure machines so trying to use the lowest figures to compare is not valid and so your ALARA comment is not applicable since the older machines have higher dosages especially for CBCT.
Your attitude to a respected professor for expressing a very valid view (which may be contrary to yours) is totally unacceptable from a fellow professional.
Just wanting to comment in reply to your post in defense of the blog author. The Ludlow guidelines from 2015 noted the “mean child doses were 175 µSv (combined large and medium) and 103 µSv (small).” I am unsure why someone would take the time to criticize a blog poster trying to provide research review to help the general orthodontic population. I appreciate the updates from this blog and try to critically evaluate the articles/information to see if applies to my practice. Often this leads me to further check the published research on topics. But to take the single lowest reported dosage of a range (CBCT) and then compare to the highest reported range possible (pan/ceph) is unfair in my mind. Not sure why quoting this except if trying to defend a clinical practice have implemented. I’d hope all doctors on here would have an open mind and not cherry pick the data to prove a point. The author even noted the research is sparse and varied on CBCT dosage…so cannot assume we are only ever giving the lowest dose to kids. IF the low dose becomes standard of care and is proven in the research, then doctors should consider switching to CBCT, but NOT before and not if potential for vastly higher dosages.
After reading both of your recent posts on CBCT, I appreciate how you flushed out your points here; they are well taken.
How ridiculous that there is still discussion about dosage in a subject that may cause cancer in children.
Routine or not, we must think twice before taking a CBCT in childeren.
Thank you very much for your sensitivity and information, Dr. O’brien.
I hope all our colleagues will show the same sensitivity.
it strikes me that this would all be solved if there were some up to date figures for dosage. Then a clinician could make an informed decision about which radiograph to take. I would expect this to depend on the machine and setting used. One would think that manufacturers would publish such dosage figures, maybe not. Without such figures arguing about it seems rather pointless.
I completely agree with your posts warning from routine use of radiographic examinations. It is hardly new information that radiation is not healthy and the correlation between radioactive radiation and cancer is a well-established fact documented and proven since decades. These facts alone should be enough for a serious health care provider to only use radiographic examinations when it is bringing new and vital diagnostic information for the treatment of their patients. A skilled and professional orthodontist have a lot of knowledge and does not necessarily need to see all details in 3D images even in impacted cuspids or cleft patients. CBCT is however, a useful tool that should, as you clearly point out, only be used in cases when things are not as expected, and when it is of great importance to our treatment plan that we acquire the information that the CBCT gives. The dosage and risks are then considered as the information from the radiographs are vital for the treatment and the wellbeing of the patient.
If we read the article quoted by Dr. DeLuke,
https://pubmed.ncbi.nlm.nih.gov/24286904/
as well as his comments on this, Dr. O’Kevin O’Brien’s blog. Once we look past the bullying, and examine the article for what it actually says, consider what information is pertinent and necessary on orthodontic radiographs, it is entirely possible to come to the conclusion that the 2024 ADA guidelines against routine use of CBCT is justified.
Within the shared article, when discussing “QuickScan+” is the quote:
*”Significant dose reductions are accompanied by significant reductions in image quality.”
This becomes an important distinction when we consider that the information on 2D cephalometric radiographs and tracings is still necessary for proper diagnosis and is not replaced by CBCT. We have almost 100 years of research on cephalometric analysis for evaluation of the patient’s current situation and growth prediction. While the original hope for CBCT was that “growth plane analysis” would eventually supersede cephalometrics, this prediction has not led to fruition and now appears unlikely to.
As a result, a practitioner wishing to provide a full orthodontic diagnosis, which includes cephalometric analysis, is left with the choice between extrapolating a ceph from a CBCT or taking a separate 2D ceph.
The issue with the former is that cephs extrapolated from low dose CBCT are of lesser quality and, from my own personal observation, frequently of non-diagnostic quality. So an extrapolated ceph, if it is to be of equivalent diagnostic quality, needs to be taken at a higher dosage. This violates ALARA, as there is a lesser dosage alternative option. The logical alternative is to take a 2D lateral ceph.
The need for a quality separate 2D ceph now being apparent, we must next consider the diagnostic value of the low dose CBCT as compared to panoramic and individual PA films. The primary purpose of which is frequently to determine the periodontal bone height, evaluate changes in root length and the presence or absence of resorption, and evaluate root parallelism.
To that end, I will share two additional quotes from the research provided by Dr. DeLuke:
• Published evidence establishing the usability of low-dose and low-quality scans for diagnostic purposes in dentistry or in orthodontics is limited.
• Additional studies are needed to confirm that other important information in 2-dimensional imaging or higher-dose scans such as gross advances in periodontal conditions, changes in root length, and changes in morphology that indicate patterns of resorption are not lost in these lowdose scans.
Research has shown that CBCT can sometimes affect the direction of eruption of traction for patients with impacted canines. However, this does not justify taking CBCT on all patients.
None of this is to say that CBCT should never be taken on individual patients. However, this is a reaffirmation of the ADA guidelines on CBCT, that they should not be taken routinely.
I think we are missing one important point in this whole discussion…marketing/sales tactics.
Let me explain. One of our neighbor orthodontists has a CBCT and takes them routinely on their new patients. Some of those patients then come to our office for a second opinion. In every case, the CBCT/lateral ceph image they bring in shows a bright red area in the pharyngeal region. The patients and parents always say that they were told by the other orthodontist this shows a “narrow airway”. In fact, the vast majority of these second opinion patients tell us that the other orthodontist said the patient was in “respiratory distress”. But wait, I thought a CBCT cannot be recommended for a valid and reliable comparison of airway dimensions for our patients.
So, I conclude that some of the doctors who insist on taking a CBCT at the initial exam are doing this (at least partially) to convince patients/parents to start treatment in their office.
“There is no safe dose for radiation exposure; radiation dose is accumulative. This is particularly important for child radiography.”
Is it still the case that the lifetime increased cancer risk in relation to age for a given uSv dose is normalized as if given to a 30yr old with the following a reasonable multiplier to keep in memory
Less than 10yrs = 3x
10-20yrs = 2x
20-30yrs =1.5x
A 50uSv panoral to a 30yr old is the equivalent lifetime cancer risk of a 150uSv panoral in a 9yr old if those multipliers are correct.
Most of my patients present with a panoral from the GeneralDentist. Very selectively do I need a pretreatment Ceph. Those instances such as direction of impacted canine traction will have a CBCT taken by the Surgeon to identify efficacious surgical access and one can read the Surgeons CBCT.
ALARA is my NorthStar.
I think a core issue is even reps are sometimes unsure what their CBCT brand does at. They are sometimes marketed as a means of giving lower dosage. For me I tend to request CBCT for impacted teeth short roots implants and jaw surgery which are not routine cases . Kind regards to all.