Abstract
Background and aims. Panoramic radiographs are used for surgical planning of unerupted third molars. The major problems
associated with panoramic radiography include unequal magnification and geometric distortion of the image. The purpose
of this study was the clinical evaluation of the effect of radiographic distortion on the position and classification of unerpted
mandibular third molars.
Materials and methods. Panoramic radiographs of 20 patients with indication for extraction of lower third molars were
included in this study. On the day of surgery, a silicon impression was taken from the second and third molar region and poured
with type IV gypsum to provide a study cast. The inclination of the lower third molar to the second molar on panoramic radiography
was compared with this angulation on the study casts.
Results. There was a mean difference of 5.75° ± 1.65 between the position of the lower third molar on panoramic radiographs
and on study casts. Student’s t-test indicated a statistically significant difference (P < 0.05).
Conclusion. Panoramic radiography tends to exhibit a more mesial position of the third molars; however, panoramic radiography
can still be used as the main tool for surgical planning of lower third molars.