Indications for Panoramic Imaging

Selection criteria guidelines are recommendations developed to assist the dentist in the appropriate prescription of dental radiographic examinations. In 2012, the American Dental Association (ADA) and the Food and Drug Administration (FDA) revised these recommendations, updating the previous version published in 2004.¹ In the updated version, the use of panoramic examinations in combination with posterior bitewings is provided as an option for imaging new patients in the child (transitional dentition), adolescent and adult categories. The application of the guidelines should be based on a clinical examination with consideration given to the patient’s signs, symptoms and oral/medical histories, as well as vulnerability to environmental factors that may affect oral health.¹ The resultant diagnostic information should help the dentist determine the type of imaging needed, if any, and its frequency. Dentists should prescribe radiographs only when they expect that the additional diagnostic information will affect patient care.¹ In addition, panoramic imaging may be appropriate in the assessment of growth and development, craniofacial trauma, third molars, implants, osseous disease or large, extensive bony lesions and the initial evaluation of edentulous ridges and temporomandibular joint disorders. Panoramic imaging is also a useful alternative technique for imaging patients with severe gag reflexes, large extensive tori or when the intraoral receptor cannot be tolerated inside the mouth.

By comparison, intraoral periapical and bitewing surveys are preferred for caries detection, identification of periapical pathology and the detection of periodontal lesions with furcation involvement. A full mouth intraoral radiographic survey is preferred when the patient has clinical evidence of generalized oral disease or a history of extensive dental treatment.^{1, 2}

Panoramic radiographic images alone or in combination with bitewings radiographs are commonly used for routine screening of all new adult patients. In 2002, Rushton et al. questioned this approach.^3,4 They found that approximately one-fifth of patients received no benefit from indiscriminate use of panoramic radiography. This proportion increased to one-fourth when asymptomatic patients were examined in isolation. They also found that clinical factors obtained from the patient history and examination modestly improved the chances of a high diagnostic yield from panoramic images. The clinical factors identified as the best predictors of useful diagnostic yield included clinical suspicion of teeth with periapical pathology, partially erupted teeth, evident carious lesions, dentition (dentate, partially dentate, edentulous), presence of crowns and suspected unerupted teeth.

In a 2012 study, Rushton et al. assessed the added value of screening panoramic radiographs compared to intraoral radiography in adult dentate patients in a primary care setting⁵. This study reaffirmed that there was no net diagnostic benefit to the patient with the use of panoramic radiographs as a routine screening tool.⁵

More recently, Benn and Vig published a study which estimated US dental practice radiographic-associated cancer cases.⁶ Findings of clinical relevance included a trend in orthodontic treatment to replace lower dose panoramic and cephalometric radiography with higher dose cone beam computed tomography and the lack of adherence to dose reduction measures by US dentists, such as the use of selection criteria to reduce radiographic-associated cancer cases.⁶

It is not only prudent but also necessary for the dentist to follow selection criteria guidelines so that the selected survey, whether intraoral, panoramic or a combination thereof, is appropriate for the patient, will produce a high yield result while minimizing radiation exposure.