Diagnostic value of extraoral periapical radiograph in comparison to intraoral periapical radiograph: A cross-sectional, institutional study

Background: Radiographs form an invaluable adjunct in diagnosis, treatment planning, and postoperative evaluation during patient management in the dental office where intraoral periapical (IOPA) radiographs are the ones most commonly used. However, certain conditions render the placement of film difficult. In such cases, a panoramic radiograph may be taken, but it has the disadvantage of higher radiation exposure and cost. Extraoral periapical (EOPA) technique allows radiographs to be taken on an IOPA film by placing it extraorally. We aimed to evaluate its diagnostic accuracy compared to intraoral bisecting angle technique. Materials and Methods: Forty-five patients were randomly selected. Ninety radiographs were taken; two for each patient. First image was obtained by intraoral bisecting angle technique and second by EOPA technique. A scale was devised for the comparison of radiographs taken by the two techniques. Two experienced oral radiologists rated them based on the scale followed by statistical analysis. Results: Patients reported increased compliance with the EOPA technique. 84.40% of the EOPA radiographs (EOPARs) were diagnostically acceptable; sensitivity and specificity was 84% and 55%, respectively. Conclusion: EOPAR is beneficial in cases where intraoral film placement is difficult, and a radiograph is necessary for patient management, even though it demonstrates comparatively lesser diagnostic accuracy.