Aim: The aim of this study was to analyse the influence of two surface modifications on osseointegration of two different implant surfaces with identical macro design and to compare the informative value of back-scatter scanning electron and light microscopy.

Methods: In 6 sheep either implants ( n = 36) with a highly crystalline and phosphate-enriched anodized titanium oxide surface (group A), or implants with a hydrophilic, sand-blasted, large grit and acid-etched surface ( n = 36; group B) were placed in the iliac shaft of the pelvis.

After 0, 2, 4, 8 weeks the total and trabecular bone-to-implant contact (BIC, n = 6) was analyzed by back-scatter scanning electron (B-SEM) and light microscopy (LM).

Results: BIC values in both groups revealed a steady rise in the trabecular bone after 2, 4 and 8 weeks (B-SEM and LM). In the 2–4 time interval in group A ( p = 0.005) and in group B ( p = 0.008) a statistically significant increase of the trabecular BIC could be observed (LM). In both groups BIC values after 8 weeks were significantly higher than after 2 weeks ( p ≤ 0.05). By using B-SEM a significant increase of total BIC values in the 0–2 time interval in group B ( p = 0.001) and a significant increase in the 2–4 time interval in group A ( p = 0.002) could be seen. There were no significant differences between the two groups at any time point.

Conclusion: The two surfaces showed comparable osseointegration in this sheep model. B-SEM demonstrated a high degree of mineralization.

Conflict of interest: None declared.