After 1 week of healing (Table 1), in the close-to-window region, the proportions of xenograft were 21.3 ± 14.7% and 55.9 ± 19.0 (p = 0.012) in the treated and untreated sites, respectively. After 8 weeks of healing (Table 2), these values decreased to a similar percentage (15.5 ± 14.4% and to 15.5 ± 14.2%; p = 0.917, respectively).

After 1 week of healing (Table 1), in the grafted sinus the highest amount of newly formed bone was found in the bone walls region (Fig. 8a), while very little or no bone at all was found in the other regions. No differences were found between treated and untreated sites. After 8 weeks of healing (Table 2), new bone increased in both sites, reaching higher percentages in the treated compared to the untreated sites in all regions. The total proportion of bone was 27.9 ± 12.9% in the treated sites and 23.6 ± 15.2% in the untreated sites (p = 0.128). The highest percentages of bone were found in the bone walls regions, being 38.0 ± 15.0% and 35.4 ± 15.0% in the treated and untreated sites, respectively (p = 0.310). New bone was still found forming ridges towards the provisional matrix, showing that the healing was not completed yet in all regions and in all sinuses (Fig. 8b).