Descriptive Histological and Histomorphometrical Comparison of Four Xenogeneic and Synthetic Bone Blocks for Mandibular Onlay Augmentation in Rabbits

Abstract

Background: This exploratory study provided a primarily descriptive comparison of two xenogeneic and two synthetic blocks for mandibular onlay augmentation in rabbits. Methods: Twelve rabbits received bilateral block grafts, providing 24 sites allocated to Bio-Oss® Block, SP-Block, ReproBone® Block, or Alos Block (n = 6/material). After 10 weeks, undecalcified sections were evaluated within standardized inferior and superior regions. Newly formed bone was the primary outcome; secondary outcomes included residual graft, IBN-like tissue, soft-tissue components, and cross-sectional augmented area. Mixed-effects models accounted for clustering within animals. Results: No statistically significant difference in newly formed bone percentage was detected among biomaterials (p = 0.475). Residual graft differed significantly (p < 0.001) and was lower for all test materials than for Bio-Oss® Block. ReproBone® Block consistently exhibited IBN-like tissue (17.3 ± 2.9%). SP-Block showed more intra-compartment soft tissue than Bio-Oss® Block. Alos Block had the smallest augmented area (12.9 ± 6.1 mm2; adjusted p = 0.001 versus Bio-Oss® Block), and extra-compartment soft tissue was present in five of six sites. Conclusions: Although newly formed bone percentages did not differ significantly, the biomaterials displayed distinct profiles of scaffold persistence, incorporation, tissue organization, and cross-sectional augmented area at 10 weeks. These features should be considered together when evaluating block biomaterials for onlay augmentation.

The authors' abstract, as published at the source. Journal of Functional Biomaterials, 2026 · DOI ↗