Accuracy of Panoramic Radiography in Determining the Distance to Anatomical Landmarks Compared to Cone-Beam Computed Tomography

The aim of this study was to determine the accuracy of digital panoramic radiography in estimating the height of bone between alveolar crest and anatomical landmarks of both jaws( maxillary sinus and inferior alveolar nerve canal) in molar and premolar areas in comparison with CBCT.

A total of 217 samples from patients who had both digital panoramic radiographs and CBCT  before implant insertion were selected. Shortest distance between alveolar crest and IANC (of mandible), and between the alveolar crest and maxillary sinus (of maxilla) in molar and premolar area has been measured. The differences of these measurements have been analyzed using paired t-test, the Bland-Altman plot and ICC.

Measurements of  panoramic radiography were significantly greater than CBCT in mandibular premolar and molar area plus maxillary premolar area (p<0.001, p<0.001, p=0.008 respectively), but the results were insignificant in maxillary molar area (p=0.147). By using ICC, the measurements were closely and positively correlated in all areas, with correlation coefficient ranging from 0.916 to 0.947. The Bland-Altman plots showed significant difference between two modalities except maxillary molar area (p<0.05).

Panoramic radiographs contain valuable information of both jaws, however they could not be reliable for meticulous measuring such as distance to anatomical regions- except posterior maxillary one - in surgeries. So that, it is essential to use precise 3D systems such as CBCT for implant measurements.