Are panoramic images reliable in planning sinus augmentation procedures?

Objective: The inherent deformation and two-dimensional nature of panoramic radiographs jeopardise their interpretation and quantitative measurements. This study aims to estimate the degree of underestimation of available mesio-distal bone in the premolar area (comparing panoramic radiographs with multi-slice/cone-beam computer tomography [CT]) to determine the prevalence, width, length and position of the bony canal [artery] in the lateral sinus wall and to explore the prevalence, width and length of another (newly detected) bony canal at the palatal aspect of the upper canine.

Material And Methods: The distance between the distal side of the canine/first premolar and the mesial side of the first molar or the anterior wall of the maxillary sinus was measured on panoramic radiographs and corresponding multi-slice/cone-beam CT images (65 patients). Measurements were made at apical, mid-radicular and crestal regions, parallel to the occlusal plane. The presence and dimensions of the two above-mentioned intra-osseous canals were verified on multi-slice CT scans (144 patients) using reformatted cross-sectional images and/or axial slices.

Results: For all 65 patients, panoramic radiographs underscored the mesio-distal distance of available bone in the upper premolar region (mean 2.9 mm, range 0.1-7.5 mm). An intra-osseous canal in the lateral maxillary sinus wall was clearly visible in 49.5% of the cases (mean diameter 1.4 mm). In the canine region, a bony canal was obvious in 32.9% of the cases, with a mean diameter of 1.23 mm. For both canals, there was no correlation between diameter and patient's age.

Conclusions: Based on the present data, cone-beam CT imaging can be recommended for visualising anatomical structures during planning of sinus augmentation procedures.