Anatomical Study of the Pterygomaxillary Area for Implant Placement: Cone Beam Computed Tomographic Scanning in 100 Patients

Purpose: The aim of this study was to describe the average angulation and dimensions of the pterygomaxillary area in the atrophic maxilla to facilitate the orientation of pterygoid implants during their placement. Materials and Methods: A retrospective radiologic study was made. A virtual pterygoid implant, 13, 15, or 18 mm long, was placed in the pterygomaxillary area following the axis of the bone, with a distance of at least 2 mm maintained between the artery and palatine nerve and the implant. The long axis of the implant was inclined slightly toward the palatal to follow the cortical palatal bone. The angles between the long axis of the virtual implant and Frankfort horizontal were measured in both sagittal and frontal views. To calculate the average length of the pterygomaxillary area, the virtual long axis of the implant was measured from the alveolar crest to the pterygomaxillary suture. Results: The average anteroposterior axis inclination of the pterygomaxillary area was 72.5 ± 4.9 degrees relative to Frankfort horizontal. The average angulation of the palatal vestibule was 81.3 ± 42.8 degrees relative to Frankfort horizontal. The average length of the pterygomaxillary area was 22.5 ± 4.8 mm. Conclusion: Pterygoid implant placement requires thorough knowledge of each patient's anatomy and individual needs. The mean position of the pterygomaxillary buttress axis was 72.5 ± 4.9 degrees to the distal and 81.3 ± 2.8 degrees to the palatal relative to Frankfort horizontal. Placement of pterygoid implants in this inclination may increase accuracy of implant placement. The average length from the tuberosity to the most apical point of the pterygoid apophysis was 22.5 ± 4.8 mm. These results suggest that an implant 15 to 18 mm in length would fit in the pterygomaxillary area to reach the cortical bone. Keywords: atrophic maxilla, implant angulation, pterygoid implant, pterygomaxillary region, radiologic assessment, tilting