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 2004.⁴ Recently a comprehensive review of dental radiation safety research, regulatory standards, and guidance from national and international agencies was completed to update several aspects of the 2012 document.³ The resultant publication of this review provides evidenced-based recommendations to assist practitioners to develop and enact safety practices that will not only optimize diagnostic image value but also minimize radiation risks to patients and personnel.³ Relevant updated evidenced-based recommendations will be discussed in the foregoing content.

Selection criteria guidelines indicate that the use of panoramic examinations in combination with posterior bitewings is an option for imaging new patients in the child (transitional dentition), adolescent, and adult categories.⁴ 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.⁴ The resultant diagnostic information should help the dentist determine the type of imaging needed, if any, and its frequency. Dentists should prescribe radiographic images only when they expect that the additional diagnostic information will have an impact on patient care.⁴ 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.^4,5

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.^6,7 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.^6,7

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 setting.⁸ This study reaffirmed that there was no net diagnostic benefit to the patient with the use of panoramic radiographic images as a routine screening tool.⁸

In addition, Benn and Vig published a study in 2021 which estimated US dental practice radiographic-associated cancer cases.⁹ 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 (CBCT) 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.⁹

Therefore, it is not only judicious but also necessary for the dentist to follow selection criteria guidelines so that the determined survey, whether intraoral, panoramic or a combination thereof, or CBCT, is appropriate for the patient and will produce a high yield result while simultaneously minimizing radiation exposure.³ The recent comprehensive review reiterated the importance of selection criteria and appropriate imaging practices to reduce radiation exposure to patients as well as adherence to all relevant regulatory requirements.³