Calcium–Chitosan Scaffolds With Simvastatin Enhance Bone Regeneration in Critical‐Sized Calvarial Defects in Rats

ABSTRACT Bone regeneration in critical defects remains a clinical challenge, motivating the development of biomaterials capable of supporting osteogenesis and modulating local biological responses. This study investigated the regenerative potential of chitosan–calcium (CH–Ca) scaffolds functionalized with simvastatin (SV) in rat calvarial critical‐sized defects. Forty male Wistar rats were randomly assigned to four groups ( n = 5 per group/experimental period): SHAM (coagulum), Bio‐Oss (xenograft), CH–Ca, and CH–Ca + SV. Defects of 5 mm were surgically created and filled according to group allocation. Animals were euthanized at 14 and 30 days, and samples were processed for histological, histomorphometric, Picrosirius Red, and immunohistochemical (BMP‐2 and osteocalcin [OCN]) analyses. Histologically, the SHAM group showed bone restricted to the defect margins with persistent inflammation, while Bio‐Oss exhibited partial bone extension and residual particles surrounded by connective tissue. In contrast, CH–Ca and CH–Ca + SV scaffolds supported linear bone formation progressing toward the defect center, with more pronounced mineralization in CH–Ca + SV. Histomorphometry confirmed higher new bone formation (NBF%) in CH and CH + SV compared with SHAM and Bio‐Oss at both time points, with CH + SV surpassing CH at 30 days. Picrosirius Red revealed greater collagen fiber maturation in CH + SV, whereas SHAM maintained a higher proportion of immature fibers. Immunohistochemistry demonstrated increased BMP‐2 and OCN expression in CH and CH + SV, particularly in CH + SV, at both 14 and 30 days. These findings indicate that SV‐loaded CH–Ca scaffolds enhance bone regeneration by promoting osteogenesis, collagen maturation, and the expression of osteogenic proteins, suggesting their potential as a cost‐effective and biologically favorable strategy for the treatment of critical‐sized bone defects.