In this study, the gradient of new bone formation during sinus floor augmentation was evaluated in the presence of an osteoinductive growth factor in 12 adult Goettingen minipigs. In a randomized split-mouth design one maxillary sinus of the animals was augmented with the alloplastic bone substitute β-TCP, whereas a combination of β-TCP and the synthetically produced osteoinductive growth factor rhGDF-5 was used on the contralateral side. To evaluate the influence of dose and time on the effectiveness of the growth factor, two different concentrations (400μg and 800μg rhGDF-5/1g β-TCP) and healing periods (4 and 12 weeks) were analyzed. After 4 weeks, improved bone formations were observed in both test groups compared to the control group, which was, however, only significantly increased in the low dose group (p=0.0184). The gradient of bone formation of both dose groups was similar to the control group with a decrease of local bone development. A homogeneous bone formation within the entire augmentation could not be detected in any of the groups after this time period. After 12 weeks, the influence of the growth factor significantly depends on the region (p=0.023). In the low-dose group, the new bone formation did not differ significantly within the examined regions of the graft (p=0,11). Thus, a homogeneous bone formation could be detected. Even after 12 weeks, the gradient of the high-dose group was similar to the control group. The highest values were measured in the region near the locally constant jawbone, from where the values decreased constantly. For control and high dose group, no homogenous bone formation could be detected. The results of the control group confirmed the development of new bone formation in purely osteoconductive bone substitute materials as described in the literature. For higher augmentation volumes and within a healing period of 3 months, a sufficient bone formation takes only place in the basal regions of the graft near the jawbone. The results of the test groups have confirmed the hypothesis that the growth factor GDF-5 leads to an increased bone formation. As described in the literature, the level of bone formation does not appear to be proportional to the dose. One reason for this could be the release kinetics of the growth factor from the adsorptively coated substrate.