A Literature Review on the Uncommon Use of Extraoral Periapical Radiography

Periapical radiography is a regular radiographic procedure performed by dentists. However, at times, it may not be possible to position the image receptor into a patient’s mouth in an optimized or practical way. For these cases, some dentists advocated the use of extraoral periapical radiography (EOPA). This literature review aimed to review the dental literature on the use of EOPA. In October 2023, PubMed, Web of Science, and Scopus were searched to identify papers that reported on the use of EOPA, supplemented by manual reference tracing and Google Scholar searches. After screening, 18 papers published between 2003 and 2022 were identified, including 14 original articles and 4 reviews. From very limited and conflicting evidence, it was found that root length/working length measurements between EOPA and IOPA did not significantly differ or EOPA showed inferiority. No data were available to compare EOPA with other extraoral modalities such as panoramic radiography. The technique used in EOPA to visualize posterior teeth in the maxilla and mandible varied across studies, such as the vertical angulation of the primary beam, whether mouth should be opened or closed, and whether a holder should be used or not. At the current time, EOPA probably should not be advocated for regular use.