“…There are reports showing a correlation between RFA and the histomorphometric analysis, and other reports claim that the correlation between the bone density and ISQ is not significant. Therefore RFA signifies the bone anchorage of implants but the relation of RFA and bone structure is not yet clear (Alsaadi, et al 2007, Huwiler, et al 2007, Rasmusson, et al 1998, Zhou, et al 2008. Such diverse results showed RFA value decreases during the first 2 weeks after implant placement, and this change can be related to early bone healing such as biological change and marginal alveolar bone resorption.…”