Title: Imaging modalities in impacted tooth assessment: A review of CBCT and parallax techniques
Abstract:
Accurate localisation of impacted teeth and early detection of associated root resorption are critical for effective diagnosis, treatment planning, and prevention of long-term complications. Conventional two-dimensional (2D) radiographic techniques, such as parallax using periapical and panoramic radiographs, have traditionally been employed to assess the position of impacted teeth and their relationship to adjacent structures. However, the inherent limitations of 2D imaging, including distortion, magnification, and superimposition of anatomical structures, may compromise diagnostic accuracy. Cone Beam Computed Tomography (CBCT) has emerged as an advanced three-dimensional (3D) imaging modality that may overcome these limitations by providing high-resolution volumetric data. This poster aims to compare the effectiveness of CBCT and the parallax technique in identifying the position of impacted teeth and detecting root resorption of adjacent teeth. A review of current literature was undertaken to evaluate diagnostic accuracy, reliability, and clinical applicability of both imaging methods. Parallax techniques rely on the apparent movement of an object relative to surrounding structures when radiographs are taken at different angulations. While parallax is widely accessible, cost-effective, and associated with relatively low radiation doses, its accuracy is highly operator-dependent and limited in complex cases, particularly where buccolingual positioning or subtle root resorption is involved. CBCT provides precise 3D visualisation of impacted teeth, enabling accurate assessment of buccolingual position, proximity to adjacent roots, and the presence, extent, and location of root resorption. Numerous studies demonstrate that CBCT is significantly more sensitive than conventional radiography in detecting early and minor root resorption, which may be missed on 2D images. Furthermore, CBCT allows for improved treatment planning and risk assessment, particularly in cases involving maxillary canines. In conclusion, while parallax remains a valuable first-line imaging technique, CBCT offers superior diagnostic accuracy for assessing impacted teeth and associated root resorption. Careful case selection is essential to balance diagnostic benefit against radiation exposure, supporting a justified and evidence-based approach to imaging.
