The CT scanning showed the following results: the angle between LBIF and the implantation route ([angle][alpha]) was 56.54 [+ or -] 2.05[degrees]; all the implant routes went through the maxillary sinus; the distance between the starting point and the endpoint was 56.85 [+ or -] 5.35 mm.
The Distance between the Starting Point and the Endpoint and the Angle between the Line Crossing the Bilateral Infraorbital Foramen (LBIF) and IA (la).
To simplify the analysis of the distribution, we set an imaginary line through the jugale point (Ju) that was parallel to LBIF (Ju-O line, Figure 3).
The angles between the line crossing the bilateral infraorbital foramen (LBIF) and IA ([angle][alpha]) in the patients with edentulous jaws were 3.27[degrees] smaller than the ones in the patients with dentulous jaws (P < 0.05), whereas the widths of alveolar crest at the starting point were 1.28 mm narrower compared to the patients with dentulous jaws (P < 0.05).
We believe that the smaller angles between LBIF and IA (la) in the patients with edentulous jaws compared to dentulous jaws contribute to the resorption of alveolar bones.