EVALUATION OF INCISIVE CANAL CYSTS: 2-D VS 3-D IMAGING. HAVE WE LEARNT ANYTHING NEW?

Abstract

<h3>Background</h3> Incisive canal cysts, also known as <i>nasopalatine duct cysts</i> (NPDCs), are developmental, nonneoplastic cysts arising from degeneration of nasopalatine ducts. They are considered the most common nonodontogenic cysts. They are usually discovered incidentally; they can occur at any age but are most commonly reported to occur in 4th to 6th decades, have a male predominance, and affect approximately 1% of the population. <h3>Objective(s)</h3> The aim of this study was to compare the radiographic features of nasopalatine duct cysts on 2-D periapical radiographs and cone beam computed tomography (CBCT) scans to understand the value of addition of 3-D imaging in the diagnosis and treatment planning of these cysts. <h3>Study Design</h3> 17 cases of histopathologically confirmed incisive canal cysts were evaluated in this study. Periapical radiographs and CBCT scans of these patients were evaluated by an oral radiology resident and a board certified oral radiologist. <h3>Results</h3> In all cases, incisive canal cysts were seen as a solitary, well-defined, oval or round, unilocular radiolucency located between the central incisors. The size varied but was larger than 0.5 cm in diameter. The 2-D images did not always confirm the diagnosis; at least 12 cases were reported as possible cysts but needed 3-dimensional (3-D) imaging for confirmation. Analyzing the same cases on CBCT scans confirmed the diagnosis. CBCT examination showed that mesiodistal extent and importantly buccolingual expansion could be evaluated. Precise measurements could be calculated to plan for surgery. In 6 cases, root resorption or tooth displacement could be seen as an additional feature on 3-D imaging. The effects of these cysts on adjacent structures, including thinning and perforation of the buccal cortical plates, could be evaluated. <h3>Discussion/Conclusions</h3> The value of adding 3-D imaging compared with 2-D imaging alone was in confirming the radiographic diagnosis, evaluation of the extent of the cysts, especially the buccolingual dimensions, and the effects on adjacent structures.