Figure 2. Load-depth curves obtained by nano-indentation of (A) the untreated trabecular bone, (B) untreated cortical bone, (C) the week 4 osseointegration interface to the machined titanium, and (D) the week 4 osseointegration interface to the acid-etched titanium. The indentation continued to the fixed depth of 500 nm with a loading rate of 10 mN/min. Note that the maximum load required to reach the 500-nm depth varied greatly among the specimens tested. (E) Biomechanical properties (hardness and elastic modulus) of week 2 post-surgery tissues at the osseointegration interface and peri-implant bone, along with the untreated trabecular and cortical bone tissues. Data are shown as the mean ± SD (n = 6). Results from a Bonferroni multiple-comparison test are indicated. Levels of statistical significance: *p < 0.05, **p < 0.01, and ***p < 0.001. (F) Biomechanical properties (hardness and elastic modulus) of week 4 post-surgery tissues. Data are shown as the mean ± SD (n = 6). *p < 0.05, **p < 0.01, and ***p < 0.001. (G) Biomechanical property comparisons of the trabecular and cortical bone between the untreated and osteotomized areas. The tissue samples were harvested 4 wks after osteotomy.