All implants resulted clinically integrated and stable into the bone tissue. No signs of tissue inflammation or infection were detected.

At low magnification, all the samples appeared surrounded by new tissue. The distinction between native tissue and newly formed bone was not clear, likely due to the fact that the latter is still in an initial forming phase. In the machined samples (group C) bone fractured trabeculae were present around the fixture apex (Fig. 5).

In some samples, belonging to the groups A and B, however, it is possible to observe some areas where a thin osteoid matrix band was directly contacted to the implant surface.

All the samples appeared surrounded by bone tissue. A thin layer of newly formed bone covered implant threads. Newly formed bone connected the fractured bone trabeculae to bone fragments and/or to the implant surface. Implants belonging to groups A and B were observed more osteogenesis areas and mineralization nuclei than implants of group C (Fig. 6).

The bone tissue layer onto SLActive and laser-treated surfaces appeared almost continuous with small marrow spaces interruption, while on the machine surface larger spaces with marrow tissue alternated with the bony trabeculae onto the titanium surface.

No implant failure was detected during the follow-up period. After 15 healing days, the mean BIC% was almost the same in groups A and B while machined implants (group C) revealed the lowest osseointegration rate value. BIC% differences between the groups were statistically significant (P < 0.05). All BIC% mean values of each group were displayed in Table 2.

After 30 healing days, groups A and B showed better osseointegration values compared to those at 15 days. Group B implants showed BIC% value significantly higher (P > 0.05) in respect with those at 15 days. Group C showed a mean BIC% value lower than that observed at 15 days. BIC% differences between groups were significant (P < 0.05). All BIC% data, after 30 days, were summarized in Table 3.