April 27, 2020

Cephalograms: Are we in need of some lateral thinking?

Lateral cephalometry has been pivotal in improving our knowledge of facial growth and response to treatment.  For example, In the 1940s and 1950s, the use of cephalograms showed that we could not change skeletal growth with inter-arch elastics. This led us to conclude that the skeletal pattern is essentially ‘immutable’. Over the years, researchers have continued to trace cephalograms to understand the relative contribution of skeletal and dental change associated with various treatments. As such, the use of cephalometry as a research tool has been indispensable and even transformational.

Of course, daily, most of us also use cephalometric radiographs to assist with our diagnosis and treatment planning. But how useful are cephalograms in routine practice? Do they provide us with critical insight that influences our diagnoses and treatment plans? Or are they unnecessary in some, most or indeed all of our cases? A team from Farmington, Connecticut did this neat study to answer these questions. The Angle Orthodontist published the paper.

Padhraig Fleming

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Value-addition of lateral cephalometric radiographs in orthodontic diagnosis and treatment planning

Authors: Anjali Dinesh; Sunil Mutalik; Jonathan Feldman; Aditya Tadinada

Angle Orthod. 2020. doi: 10.2319/062319-425.1

What did they do?

They did an analytic study to assess the effect of the inclusion (or omission) of a lateral cephalogram as part of baseline records on both orthodontic diagnosis and treatment planning decisions.

Participants: 

They selected 7 rates (3 orthodontists and 4 residents) The raters had between 1 and 10 years of orthodontic experience. Then they asked them to examine records from 100 orthodontic patients. They took this sample of patients from a private orthodontic office. It included patients ranging in age from 8 to 21 years with a range of malocclusion types.

Intervention: 

They gave the raters the patients records. These were intra-oral and extra-oral photographs, digital models and a panoramic radiograph. They asked them to complete a 7-question survey concerning diagnosis and treatment planning for each patient. Six weeks later, they gave the raters the same records for the same patients. However, on this occasion, they included the lateral cephalogram.

Outcomes:

A primary outcome was not pre-specified. However, the following areas were addressed within the 7-question survey: diagnosis (skeletal, dental or both); Angle’s classification; completeness of information; space conditions; and a perceived requirement for extractions, maxillary arch expansion and orthognathic surgery. They used kappa values to assess the agreement between the responses at the two time-points.  This is the key assessment relating to the value of the cephalogram. They also measured the agreement between raters using Cronbach’s alpha.

What did they find?

All kappa values were high (ranging from moderate to near-perfect). This suggests that the inclusion (or omission) of a cephalogram had little effect on either diagnosis or planning.

In terms of treatment planning, the agreement concerning the need for extraction, expansion and orthognathic surgery all ranged from moderate to substantial. There was less agreement concerning the aetiology of malocclusion, which may reflect the inclusion of relatively mild cases.

Interestingly, more participants did suggest that additional records would have been helpful during the initial evaluation (37%) than during the later assessment with the cephalogram available (21%). A small number of raters felt that a cone-beam CT would have been useful both during the initial evaluation (7%) and indeed, even when the cephalogram was available (5%). They also found that the level of inter-rater agreement was acceptable.

What did I think?

I thought that this was an interesting, defined study with a simple question. They wrote the paper very clearly and incorporated a thoughtful discussion of the merits and limitations of lateral cephalograms. It is not overly original, however, with numerous similar studies published in the past. Nevertheless, the findings are mostly consistent with earlier studies on this topic. They should make us question further our prescription of lateral cephalograms.

The sample size is significant, with 100 sets of records evaluated. I imagine that this would have been quite an undertaking for the raters. The number of raters was relatively low and did include more residents than qualified orthodontists. It may have been interesting to include more experienced practitioners within this cohort. Furthermore, background information, including the raters’ typical approach to imaging, would have been useful. Indeed, it would be interesting to note whether involvement in this study has influenced their own radiographic prescribing.

Final thoughts

Like much of the research we read, the findings from this study could be interpreted and applied in more than one way. The message seems to be that lateral cephalograms may have limited benefit in terms of decision-making. So should we take fewer cephalograms or at least be more discerning in terms of our use of cephalometry? Or could we conclude that we should replace the two-dimensional cephalogram with focused use of CBCT?

Have your say!

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    I totally agree with you Dr Kevin

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    Thanks Pad for the thoughtful analysis. I may also add that the thought process in this sample does not necessarily have significant external validity. There is a high likelihood that the residents and their faculty do have a common treatment decision process that a random sample of clinicians. Another way to approach this would have been to focus on a handful of scenarios were the lateral cephalogram information is more likely to influence the clinical decisions. So in those borderline clinical scenarios do the addition of lateral cephalograms modify the decision process?

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    The “limited benefit” may only be applied to these “100 orthodontic patients”. To generalise and apply to all orthodontic patients maybe overstepping the mark. Unless of course these 100 patients are representative of all orthodontic patients. With a sample size of 100 I hardly think it is likely.

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    I find this interesting as it is very rare ( if ever) that I change my initial plan based solely on values derived from a L.Ceph. I certainly do not take them at the conclusion of treatment. In extreme class 2/3’s when surgery is an option I see a need but is CBCT now nore appopriate for these patients?

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    Very well Summerized Sir. I like to add that cephalometric radiograph should be avoided if pts are having Angle’s Class I Bimaxillary protrusion, requiring extractions. Except in surgical and grow modification treatment planning , cephalometric radiograph provides no significant advantages because of softtissue paradigm.

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      Dear Kevin
      I enjoy your blogs a lot Thank you
      The same study was done by Baumrind with the same results in 1986 and he presented this at the EOS in Firenze.
      Best regards
      Birte Melsen

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    Lateral cephalograms provide information that simple photos and models cannot provide, not to mention evaluation of the CMVS and/or possible pathology. I have often times seen discrepancies in the lateral photos and cephalograms, wherein the patient has postured forward in the photo, but is in a verified occlusal contact in the cephalogram. That one piece of information can make a big difference in the treatment planning decisions. It may not happen very often, but like one terrorists who is missed in airport security, it can have a dramatic impact on the outcome.
    While the findings of this study may be a valid conclusion in regards to diagnosis in a majority of cases, it misses the point that the cephalogram is a baseline record to be able to evaluate with a later correctly done superimposition, what happened when a particular corrective strategy is used. How can one evaluate whether it was growth or mechanics that was the cause of a faulty result? How can one evaluate the claims of the effects of a particular device without a beginning ceph? I am sure the future will allow CBCT superimpositions for this, but for now, cephalograms are the best we have. We are on a slippery slope if this or any other similar research is used as a justification for incomplete records.

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      I agree. The question, “Are you attempting growth modification?” was not one of the seven questions asked. With the demise of the hand-wrist film, lat cephs provide at least some indication of growth potential (though is far from perfect) and give a clear measurement of facial height. Occasionally I am surprised at how much the soft tissues mask or worsen the underlying malocclusion or skeletal imbalance than I had guessed clinically.

      There are several problems with the paper. One of the postgrads was a first year (I was appalled by how bad some of my early tracings were at the end of training), and severity of malocclusion isn’t mentioned (eg the digital model shown in the paper looks like it is Class I with a Little’s irregularity of less than 3mm – I agree that a ceph would not change my treatment for that case). The cases are all from from one private orthodontist. This is good for comparable quality of records, but could be a highly skewed sample.
      With the current state of litigiousness in the community (a valid xray is one more level of justification for many treatment plans), the information that can be gleaned (even if it only affirms what your treatment plan is), and the radiation dose of most digital cephs being less than one day of background radiation, I think the question for me is more “why not” than “why” for the routine taking of cephs.

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    I agree with Ron. I think this is a seriously flawed study with erroneous conclusions. There was no “Gold Standard” objective criteria for either the diagnosis, or the treatment plan. In other words, the raters may have been precise, but very inaccurate.

    Precision, in the absence of accuracy or validity, is just a measure of how individuals may be consistently erroneous. Also absent, was the lack of any quantifiable treatment goals or outcome evaluation. How is one to assess the consequences of missing diagnostic information? And what would an acceptable final result look like? Those are the more relevant questions.

    Inability to completely evaluate alveolar boundary conditions, skeletal pattern, incisor position and inclination, lip-tooth relationships etc. form a potent recipe for compromised treatment outcomes, not to mention the litany of liability that will attach with treatment sans records. Like Clint Eastwood succinctly inquired, before proceeding with incomplete records, every practitioner needs to ask themselves – “Do you feel lucky”?

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      Thanks, Vijay. I really liked your last comment about “feeling lucky”! I want to reinforce what you stated about treatment objectives. How can one measure treatment objectives accomplished if one does not have a starting point. “Looks good to me and the patient is pleased” is not a good enough assessment for such a learned profession.

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      You are correct. We have been precisely measuring an inaccurate data set (lateral and maybe frontal cephs) since the beginning. Broadbent was aware of the geometric errors of projections and developed his cephalostat to take 90 degree views AND used the acetate OREINTATOR to correct for these distortions, which we di not do today. Do you want adequate imaging and adequate diagnosis or the ” Anatomic Truth” which Dr. David Hatcher and i coined. CBCT dosage is now lower than a standard pan and lateral ceph. So now what is your excuse? Costs? Well I hope your patients dont find out you are cheating them of an accurate diagnosis, treatment plan, treatment based on the patients anatomic truth , and monitoring.

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      I agree with Vishnu and Ron, so no need to reiterate their comments. I can add only that I have never been sorry, during treatment and after treating a case, to have acquired an initial lateral ceph and, in some cases, a frontal ceph; I have been sorry on occasion, though, when, for whatever reason, a ceph was not made. Lateral and frontal cephs give me the ability to quantify my clinical impression of a case and, thus, apply mechanics that I might have otherwise not deemed necessary.

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    In my opinion a bias based on previous education and use of Cephalograms exists in the interpretation and analysis of diagnostic material. Since the participants have used radiographs and have visualized tooth/jaw positioning based on previous experience/study as well as knowledge of growth and development based on Cephalograms, the results can be significantly biased.

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    My favorite paper on this topic is Moyers and Bookstein’s (1979) “The inappropriateness of conventional cephalometrics”. It was the first time that the orthodontic canon was challenged, in my experience. This current paper appears to be the final nail in the coffin. The question now is: What about the utility/necessity of 3D CBCT scans?

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    I had a look at the original paper and it just says 100 records, without further qualification. I think that would be a fair number to be representative* but I’d have to trust that it’s a reasonably well distributed range of malocclusion – there are a good few malocclusions where I don’t think the ceph would change my decision.

    That said, on occasions where I didn’t take a ceph for that (or any other) reason there have been treatments that didn’t go well and I wished I had one to go back to so I could see if there is something I didn’t allow for or if there really has been some unusual growth.

    Stephen Murray
    Swords Orthodontics

    *(but I have no idea if that’s statistically accurate, I’ve never heard of Cronbach’s Alpha)

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    I think one of the problems is we are ‘trained’ a certain way and so it becomes entrenched in our process and ‘custom’ and so very hard to let go (like etching for 20 secs instead of 60 or seeing patients every 5 weeks when we could leave it for 8 to 10 when indicated – e.g. NiTi). As clinician scientists, we should be evaluating where irradiating a patient is indicated rather than a scatter-gun approach of one in, all in as part of our routine.

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    I’m really pleased to see this study. I no longer take cephs for every dual arch treatment as I was taught. In fact at one location I work I don’t have access to a ceph, and whilst I can refer elsewhere I find that I rarely do (admittedly my case mix is purely private so less growing or severe patients). I find them most useful for the borderline orthognathic Class III. However I’d never treat without a panoramic.

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    Hi and thanks a lot for the accurate review of this paper
    i really do not understand how it is possible (with or without cephalometric analysis) to estimate things as incisors torque , occlusal plane, mandibular angle, etc …all very important informatiotions at diagnosis and in the presurgical phase ( if decided that the patient is candidate for orthognathic surgery)…I really think the cbct cannot replace lateral ceph due to the very important issue of the head positining…3d imaging is very useful instead for other reasons like the study of the dentoalveolar units, the visualization of the bony contour and the upper airways, the study of the nasal cavity and the paranasal sinuses, as third level in the tmj imaging, etc

    best regards
    nicola sgaramella, MD, DDS, PhD
    oral and maxillofacial surgeon
    sweden-italy

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    Again, just because one doesn’t take it anymore, does not de facto make this the right thing to do. There seems to be a two-tier set of outcomes – one with appropriate diagnostic records including a ceph, and one without. The real question is, which one is superior? I think we know the answer to that. For those that prefer the other outcome, a ceph may not be called for.

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    I agree with the findings that is a Ceph necessary if all you are doing is having a quick look at it. What a waste.
    But I totally disagree with the finding as at Progressive Orthodontics, we use the ceph and combine it with the models and get Visual Treatment Objectives on our computers that allows us to see what the case looks like with alignment and elastics and extractions mod and max anchorage and surgical work ups and distalisation. We can then look at the brackets required and the torque and skeletal resistance. And we can do skeletal anchorage in intrusion and headgear interaction etc etc etc. So the ceph is vital to plan a case before we even start the case.
    So we can see what a case looks like after 2 years of treatment without having to treat the case. So a ceph is totally vital if you have the latest technology to be able to use it. But if you are old school and just looking at a few numbers then you don’t need it I suppose.But you would need to start treatment and then make a treatment change during treatment. It is rare using the software and making a change in treatment during treatment.
    Bi Max cases can be visualized to see how much the bite deepens after extraction and avoid clinical issues 12 months down the track.
    So I do not like the article at all as it didn’t look at the latest software to be able to utilize a lateral ceph properly and extend its use.

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    Cephalometrics for many years has been used as an aid in diagnosis and planning. Despite its limitations, it constitutes a fundamental diagnostic element in the evaluation of severe dento-skeletal discrepancies in the anteroposterior and vertical directions. Of course, other factors must be taken into account when determining the treatment plan; the clinical experience and the individual characteristics of each case. In young patients, cephalometric assumptions are valuable in monitoring the growth trend. During treatment, partial superimpositions of the maxilla and mandible guide the clinician on the results of applied biomechanics. With regard to the study carried out, I think there was a lack of more significant sample and a greater number of experienced residents and clinicians. The CBTC exam, despite being a significant technological advance, still has limitations for orthodontics.
    Thank you.
    Sávio Prado Msd, Phd,
    Asociated Professor- Federal University of Para- Brazil

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