Three-dimensional linear and volumetric analysis of maxillary sinus pneumatization

Abstract

Considering the anatomical variability related to the maxillary sinus, its intimate relation to the maxillary posterior teeth and because of all the implications that pneumatization may possess, three-dimensional assessment of maxillary sinus pneumatization is of most usefulness. The aim of this study is to analyze the maxillary sinus dimensions both linearly and volumetrically using cone beam computed tomography (CBCT) to assess the maxillary sinus pneumatization. Retrospective analysis of 30 maxillary sinuses belonging to 15 patients' CBCT scans was performed. Linear and volumetric measurements were conducted and statistically analyzed. The maximum craniocaudal extension of the maxillary sinus was located around the 2nd molar in 93% of the sinuses, while the maximum mediolateral and antroposterior extensions of the maxillary sinus were located at the level of root of zygomatic complex in 90% of sinuses. There was a high correlation between the linear measurements of the right and left sides, where the antroposterior extension of the sinus at level of the nasal floor had the largest correlation (0.89). There was also a high correlation between the Simplant and geometric derived maxillary sinus volumes for both right and left sides (0.98 and 0.96, respectively). The relations of the sinus floor can be accurately assessed on the different orthogonal images obtained through 3D CBCT scan. The geometric method offered a much cheaper, easier, and less sophisticated substitute; therefore, with the availability of software, 3D volumetric measurements are more facilitated.

Keywords: CBCT; Linear measurements; Maxillary sinus; Pneumatization; Volumetric measurements.

Fig. 1

(A) Adjustment of coronal cut at area of intended measurement by rotation of the axial image till the orientation axis for the coronal cut (blue line) becomes perpendicular on buccal cortex. This adjustment was repeated at interdental areas between upper first and second premolars, upper second premolar and upper first molar, upper first and second molars, upper second and third molars; giving rise to 4 craniocaudal measurements CC 45, CC56, CC 67, and CC78 respectively for each side. (B) The four areas intended for craniocaudal measurements represented on the sagittal cut. (C) Coronal cut revealing the actual craniocaudal measurement conducted along the orientation axis for the sagittal cut (bluish-green line).

Fig. 2

(A) Antroposterior (1 and 3) and mediolateral (2 and 4) measurements conducted along the nasal floor (AP NS, ML NS) on axial CBCT scan. Coronal (B) and Sagittal (C) cuts showing the axial orientation axis (red horizontal line) denoting the level of axial scan along the nasal floor.

Fig. 3

(A) Antroposterior (2 and 4) and mediolateral (1 and 3) measurements conducted along the root of zygoma level (AP ZG, ML ZG) on axial CBCT scan. (B) Coronal CBCT scan showing the axial orientation axis (red horizontal line) denoting the level of axial scan along the root of zygoma.

Fig. 4

Mediolateral dimension of the maxillary sinus conducted on coronal (A) and axial (B) CBCT scans to calculate the height of the pyramidal sinus. Antroposterior and craniocaudal dimensions conducted on sagittal (C) CBCT scans to calculate the surface area of the pyramid’s base (width and length). (D) 3D volumetric measurement of the maxillary sinus using the Simplant software.