Cone-beam computed tomographic evaluation of bone engagement in 2 orientations of pterygoid implant placement

Background Pterygoid implants can be placed in different orientations. This study compared 2 distinct implant trajectories in terms of bone engagement and implant characteristics. Methods Dedicated planning software was used to review cone-beam computed tomography data sets and to position virtual implants within the pterygomaxillary complex. The following measurements were made on cross-sectional, panoramic, and modified buccopalatal reconstructions: the total bone length along the implant axis, the length of bone engagement, anteroposterior and buccopalatal angulations, and the mesiodistal position of the osteotomy. Results A total of 169 pterygoid regions with 169 implants per implant-trajectory group were included in this study. The high-trajectory group exhibited a mean (SD) total osseous length of 19.9 (3.2) mm, significantly greater than the 17.9 (3.3) mm recorded for the low-trajectory group ( P < .001). The pterygoid-process penetration (SD) was also greater in the high-trajectory group (8.7 [2.8] mm) than in the low-trajectory group (5.8 [2.3] mm; P < .001). With respect to the virtual implant length, the high-trajectory group required a longer fixture than the low-trajectory group (mean difference, −2.0 mm; P < .001). The linear mixed-effects model was used to compare all parameters. Conclusions High-direction pterygoid implant placement achieves deeper purchase within the dense pterygomaxillary complex and therefore offers superior virtual bone engagement. Across both orientations, an implant length of 16 through 20 mm is selected most frequently.