THE ACCURACY OF PANORAMIC RADIOGRAPHY AND CONE BEAM TOMOGRAPHY FOR MEASUREMENT OF THE ANGULATION OF LOWER THIRD MOLAR

• DOI: 10.22533/at.ed.15931012308126

• Palavras-chave: Dente Impactado; Radiografia Panorâmica; Tomografia Computadorizada de Feixe Cônico.

• Keywords: Impacted tooth; Panoramic radiography; Cone-beam computed tomography.

• Abstract: Introduction: Panoramic radiography (PR) is widely accepted as the method of choice for surgical planning for lower third molars (L3M), however, it is limited by distortions inherent in the images. Objectives: The aim of this study was to evaluate the accuracy of PR and cone-beam computed tomography (CBCT) scans in determining the angle of the L3M, estimate the angular distortion caused by the examinations, the appropriate view, and propose the optimum position for the patient’s head during the examination for less image distortion. Materials and Methods: An in vitro study was performed with a set of 16 molars matched with each other and a dry human jaw osteotomized in the molar region with preservation of the lingual cortical bone to serve as a bed for fixing teeth at angles of 30°, 45°, 60°, and 90° to their long axes. The set was submitted to PR and CBCT imaging examinations changing the Frankfurt plane using a predefined template with angles of 15°, 25°, and 35°. Results: The angular difference was less with CBCT compared with the gold standard for 48 images; the difference was statistically significant (p <0.05). Conclusion: Compared with the gold standard, the L3M are positioned more vertically on PR, which shows a more mesial position. In this context, a change in the mandibular plane of 35° could presumably minimize this distortion. CBCT is the ideal imaging modality to evaluate the position of L3M.