Diagnostic imaging for acute pain in a pregnant patient

Clinically justified diagnostic imaging is not contraindicated in pregnancy, and the standard is the same as for any other patient: take the images needed to make the diagnosis, using the smallest dose that answers the question. What changes is not the indication but the technique - collimation, shielding, receptor choice, and refusal to accept retakes.

Her symptom pattern is the reason this is not a discretionary film. Pain that wakes her at night and lingers after a cold stimulus points to irreversible pulpitis, and irreversible pulpitis progresses to pulp necrosis and then to periapical infection. An untreated dental infection in pregnancy carries real risk - pain, poor nutrition, and eventually antibiotics or emergency care under worse circumstances - and treating it later means more appointments and more imaging, not less.

Radiation risk framing that is honest and useful: the fetal dose from a shielded intraoral periapical is on the order of a small fraction of a milligray, far below the 50–100 mGy threshold at which concern about deterministic effects begins, and well under the background radiation she receives over the course of the pregnancy. Nondiagnostic imaging is the actual harm to avoid. Also note that the second trimester is the preferred window for elective treatment; urgent treatment is appropriate in any trimester.

Choose:

• Digital intraoral receptors rather than film - roughly half or better dose reduction relative to D-speed film, with no loss of diagnostic yield.
• Rectangular collimation with the matching receptor holder; this cuts the exposed tissue volume substantially compared with round collimation and simultaneously reduces cone-cut retakes.
• A size-appropriate receptor and a lead apron with thyroid collar.
• A single, well-positioned periapical of the symptomatic tooth plus the bitewing only if the bitewing adds information - for example, to check interproximal caries on the adjacent teeth at the same time.

Avoid:

• A full-mouth series or panoramic as a 'while we're here' baseline. Neither answers the question in front of you, and the panoramic is not a substitute for a periapical in this situation.
• Retakes caused by sloppy technique. The single biggest dose multiplier in intraoral radiography is repeating an image because the receptor was not positioned properly. Do it once, correctly.
• Any film-processing step that invites a repeat, and any CBCT for a question an intraoral image can answer.

Honor the refusal, but do not let it turn into treatment without a diagnosis.

What you can do: a thorough clinical examination, pulp sensibility testing (cold and percussion), periodontal probing, transillumination, and a careful visual caries assessment. Explain in plain terms what you can and cannot determine without the image - restorability, caries depth relative to the pulp, and periapical status are the specific unknowns.

What you should not do: proceed with an irreversible restoration or an extraction on a presumed diagnosis, or hand over a prescription to substitute for one. 'Just clean the tooth' is not a treatment plan; without knowing whether the pulp is irreversibly inflamed, the patient may leave with a temporary that fails and no improvement.

Documentation: record that the diagnostic images were recommended, the reason they were recommended, that the risks of declining were explained in terms she confirmed understanding of, and that she declined. Record the clinical findings you did obtain. Offer a written summary and an open door - patients frequently accept imaging after the pain escalates or after they speak with their obstetric provider.

Interim management: analgesia appropriate for pregnancy in consultation with her obstetric provider, and a scheduled follow-up. If swelling, fever, or trismus develops, that is a different and more urgent conversation.