Comparative Histological and Histomorphometric Analysis of Xenografts and Synthetic Biomaterials in Rabbit Sinus Floor Elevation.

BACKGROUND

This study compared four biomaterials after maxillary sinus floor elevation in rabbits, focusing on graft persistence, tissue organization, space maintenance, and Schneiderian membrane response.

METHODS

Thirteen adult New Zealand White rabbits were enrolled, including 12 males and one female replacement animal; 12 animals provided evaluable specimens, with six assigned to each healing interval. Four elevated sinus compartments per evaluable animal were randomly allocated to Bio-Oss®, mp3®, ReproBone® novo Paste, or Alos Granular. Specimens were collected after 2 or 10 weeks (n = 6 each). Histomorphometry quantified new bone, residual graft, soft tissue, elevated area, mucosal alterations, and IBN-like tissue, defined as areas in which biomaterial and bone could not be reliably separated. A combined graft and IBN percentage was calculated.

RESULTS

At 10 weeks, materials differed in residual graft (p = 0.0040) and combined graft and IBN percentage (p = 0.0218); Bio-Oss® showed higher values than Alos Granular for both outcomes (adjusted p = 0.0024 and 0.0219, respectively). IBN-like tissue was higher in ReproBone® novo Paste and Alos Granular than in Bio-Oss® (adjusted p = 0.0219 and 0.0417), whereas only a small proportion occurred in mp3®. New bone did not differ among materials at either interval. Bio-Oss® and mp3® showed predominantly conventional osteoconduction. Alos Granular showed extensive degradation, whereas ReproBone® novo Paste exhibited irregular graft and IBN regions. In the descriptive mucosal assessment, thinning was observed in all groups, whereas perforations were observed only at Bio-Oss®-treated sites; no inferential comparisons were performed for these outcomes.

CONCLUSIONS

The materials differed in graft persistence, tissue architecture, dimensional stability, and mucosal response. Sinus graft evaluation should extend beyond new bone formation to include residual graft, IBN-like tissue, space maintenance, and mucosal compatibility.