When looking into the Kaplan-Meier implant survival curves of the augmentation procedures using the log-rank test, the highest implant survival was found for bone condensing followed by lateral augmentation, internal sinus lift, transplantation of bone blocks, bone splitting/spreading, titanium mesh, external sinus lift (one- and two-step) and finally, no augmentation. This sequence was statistically significant (p = 0.0336).

Membranes

In 36.6% of all implant sites, a membrane was used. In 74.0% of these sites, the native collagen membrane Geistlich Bio-Gide was applied. Other often used membranes were Geistlich Bio-Gide combined with other membranes (7.38%), the non-resorbable Gore-Tex membrane (6.19%) and Vicryl (6.03%).

In pairwise comparisons vs. no membrane, significantly increased rates of implant loss were found for Kollagen Vlies and Resodont, although the sample sizes were quite small (Table 4). When evaluating the Kaplan-Meier implant survival curves for the membranes (Fig. 3) using the log-rank test, the following sequence for implant survival was found (p = 0.0009): Geistlich Bio-Gide (highest survival), Gore-Tex, Tefgen, Ossix, Biovin, Ossoguard, Epigude, Inion, Geistlich Bio-Gide in combination with other membranes, Vicryl, Resodont, Kollagen Vlies, Tutodent, and no membrane (lowest survival).

Graft materials

The graft materials used most often were the deproteinized bovine bone mineral, Geistlich Bio-Oss (53.0%) and autogenous bone particles (32.5%). The use of both graft materials resulted in higher absolute implant survival assessing the data to no graft material (p = 0.0104 and p < 0.0001). In contrast, Cerasorb showed lower implant survival compared to no graft material (p = 0.0002). For the other materials, no differences were found (Table 5).

When comparing the Kaplan-Meier implant survival curves of the grafts (Fig. 4) to each other using the log-rank test, the following sequence for implant survival was found (p = 0.0001): Geistlich Bio-Oss (highest survival), other bone substitutes, autogenous bone particles, Geistlich Bio-Oss + Cerasorb, Bioresorb, Cerasorb and no graft material (lowest survival).