Aim: To check the reliability of panoramic radiographs in assessing mesiodistal angulations while considering the true long axes of teeth in relation to a horizontal reference archwire. Method: A clear anatomical typodont with removable teeth was used with 0.8-mm chromium steel balls glued over the incisal/occlusal and apical/furcal portions of teeth to serve as reference markers for representing true long axes of teeth on radiographs and photographs. A photograph of each tooth was taken with a particular technique to serve as a medium through which to measure true mesiodistal angulations of teeth. Results: Only overall maxillary teeth angulations significantly correlated to true mesiodistal angulations. Radiographic relationship of the long axes of adjacent teeth (convergence or divergence) in the mandibular as well as the maxillary arch did not show any significant correlation to true degree of convergence or divergence and displayed a tendency to accentuate the maxillary canine to premolar divergence and mandibular lateral incisor to canine convergence. Conclusion: Panoramic radiographs provide a poor representation of the mesiodistal angulations of teeth and require cautious use with clinical judgment and adjunctive procedures to ascertain root angulations. Orthodontics (Chic) 2011;12:96–107.
Key words: tooth angulations, panoramic radiograph, true long axis, photographic technique