The impact of regional bone dimensions on the selection of pterygoid implant directions: a radiographic study

Aims
This investigation sought to delineate the bone morphology of the pterygomaxillary complex across various vertical planes and, furthermore, to clarify the extent to which anatomical bone characteristics inform the choice of pterygoid implant orientation. 

Materials and methods
Cone-beam computed tomography scans were analysed using specialised software. Measurements related to bone dimensions, density, and implant direction were recorded in the panoramic and multiple axial planes.

Results
A total of 188 pterygoid sites were analyzed. The mean vertical bone height of the pterygomaxillary complex was 13.6 ± 2.7 mm. Bone width and thickness were significantly lower in the superior plane than in the inferior plane (width: mean difference 1.7 mm, 95% CI: 1.4–2.0, d = 0.9; thickness: mean difference 1.0 mm, 95% CI: 0.8–1.3, d = 0.7; both p < 0.001). Bone density in the pterygoid region was significantly higher than in the tuberosity (mean difference 526.5 GSD, 95% CI: 475.0–577.9, d = 1.5, p < 0.001). Most sites (80.9%) allowed implant placement in both low and high orientations. In contrast, 16.5% of sites permitted only the low orientation due to insufficient superior bone. Sites limited to low-orientation placement exhibited significantly reduced bone thickness compared with sites permitting both orientations (inferior plane: mean difference −1.9 mm, 95% CI: −2.3 to −1.5, d = −1.3; superior plane: mean difference −1.9 mm, 95% CI: −2.3 to −1.4, d = −1.1; both p < 0.001).

Conclusions
Bone dimensions of the pterygomaxillary complex decrease progressively at more superior levels. Most sites accommodate both low- and high-orientation implant trajectories, whereas insufficient superior bone restricts placement to a low-orientation pathway.