Figures 5–8. Figure 5. Backscatter scanning electron microscope (SEM) micrograph of machined implant placed by the press-fit technique showing a fracture line at the implant interface as a consequence of the removal torque test (original magnification ×500). The occurrence of the interfacial failure confirms the rigid implant-bone fixation. Figure 6. Backscatter SEM micrograph of a machined implant placed by the press-fit method (original magnification ×15). The trabecular nature of the bone surrounding the implant can be observed. Bone tissue has grown in the majority of the screw-threads. The amount of bone contact at the flat implant part is very limited. Figure 7. Backscatter SEM micrograph showing the threaded part of an etched implant placed by the press-fit technique (original magnification ×75). Again, the fracture line caused by mechanical testing can be seen at the implant interface. There is bone-to-implant contact with one of the screwthreads (right hand bottom corner), but no bone contact is present with the other screw-threads. Figure 8. Backscatter SEM micrograph of an etched implant placed by the osteotome approach (original magnification ×15). The bone that surrounds the implant has trabecular morphology. The amount of bone contact is very limited and occurs with only a few tips of the screw-threads