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A Legal Insight Into Dental X-Rays

by Dr. Stephen Bray

We live in an age of increasing expectations; of this we’re reminded daily. As this occurs we have to protect ourselves from others’ unreasonable expectations. This implies that we have insight into what are ‘reasonable expectations’. These may be guided by our own experience and governance or by guidelines from a special interest group or authoritative body. Sometimes the reasonable expectations fall in-between these and the onus is on the practitioner to deliver care and service to protect both the patient and themselves.

Dental X-Rays

Radiographic (X-ray) imaging is a case in point. The acronym ALARA (as low as reasonably achievable) should remain in the forefront of dentists’ minds throughout. Why is the radiograph being taken, for what purpose - diagnosis, screening or another reason?

Dental X-Rays and Cancer

Do dental x-rays cause cancer? There is no doubt that ionising radiation (of which an example is x-rays) has that capability. There have been studies that have shown an increase in non-malignant meningioma, hence the American Dental Association’s new guidelines of adult “Bite-wing” x-rays every 2-3 years if appropriate. Children under 10 appear to be more susceptible.

Insight and Rationale

Why is the radiograph being taken, for what purpose, diagnosis, screening or another reason?

The use (and abuse) of x-rays in dental practice goes back many decades and during this time we’ve moved forward in many respects, although “the jury is still out” on some issues – a primary example being the use of neck (or thyroid) collars during radiograph taking. It is clear when reviewing literature on this, that whilst there are “guidelines,” they are both open to interpretation and, to some extent, modifiable by the clinician, depending on the clinical situation.

It must be remembered that like other ‘tests,’ radiographs are an adjunct to diagnosis or screening and should not be relied upon alone. Consequently, if the dentist takes a radiograph, there must be a clinical reason for doing so. It becomes clear therefore, that a radiograph can only be made following a clinical examination.

When To Take a Radiograph

If radiographs are taken in response to a clinical suspicion, grounds for that suspicion must be noted. If the radiograph is being taken in order to develop a diagnosis and form a treatment plan, then a note of this rationale must also be made. Radiographs should only be taken when clinically necessary. The dentist remains responsible for the clinical decision reasoning, so taking radiographs on the request of third parties for administrative purposes alone would be difficult to support in a court of law based on unnecessary exposure.

Radiograph Notation

Consent for any test should be made, including radiographs, and this consent may be performed as a test alone or part of overall consent for dental treatment.

Dated notation of findings is important for any diagnostic test, including radiographs. Not every image shows what is intended and when the need to retake one is indicated, its retaking must be checked with the patient and noted, and the image retained. Notation of the absence of findings, “nothing abnormal discovered” (NAD), is usually acceptable when no evidence of pathology or sub-optimal dentistry is observed.

The reason, type, and number of radiographs must be noted, even if one or more are repeats. As discussed above, a decision to retake a radiograph should not be based on ideal technical requirements, but on a lack of necessary diagnostic information on that just taken. Failure to take radiographs when necessary, poor diagnostic quality and/or failure to check them (“if its not written – it didn’t happen”), are a common basis for a claim of negligence.

Some form of quality assurance is recommended. Even a notation as a tick or (digital) notation for good image (if it is) is likely sufficient. Radiograph images remain an indispensable mainstay of a dental practice, and should be retained for the same length of time as other records. They are confidential and should not be shared with clinicians (or others) without the patient’s permission.

Why Take a Radiograph

It is recommended that a radiograph is taken of any tooth to be restored or removed before treatment consent and intervention. Any pathology such as caries, bone loss, sub-optimal treatments (e.g. inadequate endodontic intervention), sub-gingival calculus or other lesions/pathologies must be noted. If discussed with the patient, this must also be noted.

Diagnostic Interpretation of a Discovered Lesion

A potentially enlarging lesion, affecting adjacent teeth or tissues or one of a suspicious nature, should alert the dentist to seek referral to either a dental radiologist or a maxillofacial surgeon, informing the patient ‘s medical doctor by copy. The patient must always be consulted and given their options, and referral must be managed in a timely fashion.

A referral package should comprise of (regardless of format):

  1. Patient demographics (contact information)
  2. Medical and dental history
  3. Signs (seen) and symptoms (experienced) relating to the lesion if any
  4. Notation of the nature of the lesion (location, size, history, anatomical associations and reason for review/referral)
  5. While a specific diagnosis doesn’t have to be made, differential diagnosis may assist

A timely referral is paramount, not only to the patient’s health and welfare, but also to potential liability should these actions not take place.

The radiograph should be copied and/or sent (depending on format) after having the patient consent for referral (preference is that this should have already been performed, allowing free sharing of information with and between other professionals). Although copies may reasonably be sent (most states accept this to carry a fee) the original image must never leave the dentist’s office avoiding the inability to rebut a claim.

The dentist should follow-up with the specialist’s office to ensure receipt of the information and notations made.

For a lesion, which is chronic, asymptomatic and well-delineated, referral should still be made, and like the above, noted carefully. Throughout referral, sensitive language should be used for the patient, encouraging a review and diagnosis without alarm or panic as that failure to do so also presents a future liability.

Most dentists would agree that early caries might not necessarily be restored. While studies have shown that radiographs alone may not be accurate, if a decision is made to do this, it is absolutely crucial to tell the patient and explain why you recommend this approach in this case, and without promise. To provide supportive therapy (diet, cleaning, fluoride, etc.) and office information sheets, ideally by way of pamphlets which are therefore consistent in content, strengthens rationale, the dentist-patient bond and reduces misunderstandings between that approach and other dentists. This avoids the appearance of the “watch and wait” mentality, which can be very difficult to legally defend. The patient should sign indicating they understand the benefits and shortcomings. The lesions should be noted and this retained with the imaging and a review date made to determine if it is stable or deteriorating.

Diagnostic Screening - Interpretation of Potential Lesion Suspected

It is becoming more difficult to justify procedures based on a “the dentist always does that” rationale. Historically, many dentists have taken x-rays because they always do, often “looking for cavities.” At the other end of the range, “I don’t need them - after all these years I can tell if someone has a cavity,” is equally as legally indefensible.

Two last points need clarification. The dentist prescribes the radiograph and may do it themselves or have a team member take it under their prescription. It is the dentist who reads and interprets it, hence the importance of looking at it and reporting on their findings. While there is a tendency to “look for things” (i.e. cavities) rather than perform objective observation, most dentists are fairly proficient in the interpretation of basic dental radiographs e.g. ‘Peri-apical’, ‘Bite-wing’ or ‘panorex’ (orthopantograms) images. The duty of care may require diagnosis from the image adequately, and to the level expected. With the increased use of more complex imaging, for example, Cone beam computed tomography (CBCT), the dentist is now required to report on far more complex information, despite the fact that they may only be taking it for one reason.

Regardless of this, the dentist retains the duty of care to read the image adequately throughout, so a full review of the complex image must be performed and reported upon - the practice of obtaining a radiologist’s report to ensure “nothing is over-looked” is to be encouraged.

From this it may be seen that these complex images are often taken for one reason, but must be reviewed throughout. These machines are expensive and may be utilized extensively. The use for certain purposes must be reviewed; images taken to visualize the airway when sleep disordered breathing is suspected (snoring and obstructive sleep apnea) presently has no clinical basis. Firstly, the dentist is performing a test to investigate a medical condition; secondly, to date there has not been shown (in peer reviewed literature) any justification for doing so. I believe that both of these issues would be difficult to defend in court.

With safe exposure, evidence-based practice, and patient-centered service using local (state, provincial) guidelines for operator, patient and others’ safety, dental radiology may be considered to be of great healthcare benefit. Failure of insight or failure to comply with guidelines, however, rapidly centers liability on the individual dentist and the potential for a claim of clinical negligence increases significantly. This is a fact of which the dentist must remain fully cognizant.

The above is my own opinion as of the time it was written; November 2018. Accepted techniques, knowledge, belief and opinion change with time. Circumstances may be different between patients and situations, reflecting appropriateness under a particular scenario. Therefore, the above is simply an outline to which thought might be given, but not necessarily acted upon.