Validation of dental panoramic radiographs for the localization of impacted maxillary canines

Abstract

<b>Objective:</b> The purpose of the study was to assess the reliability and validity of panoramic radiographs in localizing impacted maxillary canines (IMCs).<br> <b>Materials and Methods:</b> The study group consisted of nine patients of either sex in the age group of 13-30 years with unilateral or bilateral impacted maxillary permanent canines. The study subjects were selected from outpatients attending the Department of Oral Medicine and Radiology of Rajah Muthiah Dental College and Hospital, Chidambaram. One of the patients had bilateral impactions resulting in 10 IMCs. The patients were subjected to undergo intraoral periapical (IOPA) radiographic examination using the same-lingual, opposite-buccal (SLOB) technique and the bucco-palatal position was assessed. Later, an orthopantomograph (OPG) of the same patient was taken and the position of impacted permanent maxillary canine was determined by applying vertical restriction and magnification criteria. Spiral computed tomography (CT) scan was performed for each and every patient and the images obtained were reconstructed by three-dimensional (3D) rendering. Surgical exposure was done for the confirmation of the results obtained from the three methods and was considered as the gold standard for authentication of the results.<br> <b>Results:</b> IOPA, axial CT, and 3D reconstruction revealed 100% agreement of the results on surgical exposure, whereas OPG using the magnification criteria showed 80% agreement and OPG using the vertical restriction criteria showed only 50% agreement on surgical exposure. The results obtained using the vertical restriction criteria proved to be insignificant.<br><b>Conclusion:</b> OPG can be used as a reliable screening aid in localization of IMCs by using the magnification criteria. The use of a single panoramic radiograph to localize the IMC will, therefore, reduce the cost and amount of radiation exposure to the patient. The OPG is more precise than accurate because it only projects the two-dimensional image of the IMC.