Displacement of Dental Implants in Trabecular Bone under a Static Lateral Load in Fresh Bovine Bone

Aim: The study aims to provide objective data for the displacement of titanium screw implants in trabecular bone specimens. One hundred Semados implants (Bego, Bremen, Germany) were inserted in bovine type IV bone specimens. All implants had a diameter of 3.75mm; 50 implants had a length of 8.5mm and 50 implants had a length of 15mm. Insertion torque was determined at intervals of 10, 20, and 30Ncm. Implants were loaded horizontally with 10, 20, and 30N for 2 seconds. An indicator strip was attached to the implant abutment to allow direct observation of implant movement relative to the bone surface. Horizontal displacement was assessed with an accuracy of measurement of 10 mu m. Seven implants got lost by visible loosening. Degree of displacement was subject to evaluation with all others. Those implants showed a mean displacement of 59 mu m for 10N (n=100), 173 mu m for 20N (n=99), and 211 mu m for 30N (n=93). The mean displacement of 15-mm implants (16, 37, 51 mu m) was significantly lower compared with 8.5-mm implants (103, 311, 396 mu m) corresponding to 10, 20, and 30N as lateral loads. Conclusions: Displacement of screw implants in trabecular bone can be detected and visualized using commercially available endoscopes with a high magnification. A lateral load of 20N indicates a mean displacement of over 100 mu m and therefore results in a critical displacement.