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Considering CBCT

24 October 2019

One of the most spectacular examples of new technology in modern dentistry is the increasing use of cone beam computed tomography (CBCT). Dentolegal consultant Jim Lafferty looks at the technique’s main areas of awareness and key risks.

The improvements in assessment, diagnosis and treatment planning are well known – in the fields of implant placement and third molar surgery we have seen significant uptake, and our endodontic specialist colleagues are now also seeing the benefits of using it and how it can improve results for patients.

The use of such technology to improve patient care and reduce risk will be an attractive proposition to all involved, but there are potential pitfalls – awareness of these is vital, particularly given the high costs associated with purchases of this type. 

There is a considerably higher exposure to ionising radiation that increases the risk of developing a malignancy, so we should all be able to justify why any CBCT is being used, even if you are prescribing the imaging to be taken elsewhere. There is now a legal requirement to record this justification in writing. Members in other regions where a written justification and report is already mandatory report that this means they are more careful to consider both the benefits and the risks associated with CBCT, and, as a result, have reduced the numbers of CBCT images that they take, reducing the amount of exposure to ionising radiation. 

If you are responsible for assessing the resulting image you should ensure that you can demonstrate that you have suitable training for this and make a written record of your assessment of the entire dataset. There are enormous amounts of information to be gleaned from these x-rays, and the person reviewing the slices has the responsibility to check for pathology in all those slices – even at sites distant to the area of interest. Any practitioner providing a radiological report should hold an appropriate Annual Practising Certificate, and maintain their knowledge through continuing education and training, particularly if new equipment or techniques are adopted.

In the accompanying case report, you will see that it is very important to establish who will be reporting on the image. 

The key points dentists should consider in the area of CBCT are:

  • Arrangements – who will be responsible for reporting?

Dentoalveolar: For CBCT images of teeth, their supporting structures, the mandible and maxilla (to floor of nose), an adequately trained GDP or dental specialist may do the report.

Non-dentoalveolar: For craniofacial CBCT or non-dentoalveolar small fields (eg temporal bone) the report should be made by a suitably trained specialist.

  • Assess – a CBCT without a prior clinical examination is very difficult to defend.
  • Balance – the risks of ionising radiation against the clinical information gained (the benefits).
    Will the CBCT potentially add new information to aid patient management?
  • Minimise – can the same information be obtained with a lower dose alternative x-ray, or by a smaller field or resolution of CBCT?
  • Justification – record in writing the reason for taking the x-ray.
    This should demonstrate the benefits outweigh the risks
  • Prescribe – an appropriate resolution and volume (size of field)
  • Report – there must be a written report of the entire dataset, leading to your normal recording of diagnosis, discussion of treatment options, planning, risk and consent.

Case study

Mr D was referred to an oral surgeon for pain related to his temporomandibular joint (TMJ) issues. During the early assessments, a CBCT was prescribed, carried out in a remote CBCT and imaging centre, with a specialist radiologist report ordered. Over a year later a further CBCT was ordered from the same centre when symptoms had spread. 

The patient went on to develop a cancerous neuroma in his tongue, which by now had spread into the lymph nodes, and was considered inoperable.

The family complained to the regulator, and the oral surgeon contacted Dental Protection. He was particularly concerned, as his records of the patient’s treatment were somewhat brief and generally of a low standard, however, with assistance from Dental Protection the member was able to show that he had ordered specialist reports, and that the developing neuroma had been missed in the original scan. It was put forward that the responsibility for failing to diagnose the tumour was not the oral surgeon’s. We then worked closely with the member on developing a CPD programme around record keeping, so that by the time of the hearing, he was able to demonstrate that he had shown insight and taken steps to remediate.

Naturally the member was keen to emphasise in his response to the Dental Council how distraught he was at hearing the news but that he did not consider the complaint showed any wrong doing on his part. This was recognised by the Dental Council and the case was dismissed.

Learning points

  • By having the image reported on by an appropriate specialist, the responsibility for spotting pathology outside the area of interest is not the dentist’s.
  • All x-rays should have a written report

These case studies are based on real events and provided here as guidance. They do not constitute legal advice but are published to help members better understand how they might deal with certain situations. This is just one of the many benefits Dental Protection members enjoy as part of their subscription. 
For more detailed advice on any issues, contact us