# Evaluation of Two Alloplastic Biomaterials in a Critical-Size Rat Calvarial Defect Model

## TL;DR

This study compared two bone graft materials in rats and found they did not significantly improve bone regeneration compared to a control.

## Contribution

The study evaluates two alloplastic biomaterials in a rat model for bone regeneration, focusing on their structural integrity and new bone formation.

## Key findings

- No significant differences in mineralized tissue volume or residual biomaterials were observed among groups.
- Sham surgery showed higher bone area fraction than some biomaterials at 2 weeks, but not at 6 weeks.
- Biomaterials maintained structural integrity with limited new bone formation comparable to sham surgery.

## Abstract

Aim: to evaluate the bone regeneration capacity of two alloplastic biomaterials in a critical-size rat calvarial defect model. Methods: A total of 80 rats were randomized into 8 groups of 10 animals each. An Ø8 mm, critical-size calvarial defect was created, and the following treatments were randomly allocated: sham surgery, deproteinized bovine bone mineral (DBBM) + collagen membrane (CM), poly-(lactic-co-glycolic-acid) (PLGA)-coated pure phase β-tricalcium phosphate (β-TCP), or PLGA-coated 60% hydroxyapatite (HA):40%β-TCP. Animals were allowed to heal for 2 and 6 weeks. Microcomputed tomography (μCT) was used to evaluate mineralized tissue and biomaterial displacement. Histological samples were used to evaluate new bone formation. Results: μCT analysis showed no significant differences among groups for total volume of mineralized tissue or residual biomaterials. DBBM + CM showed significantly increased horizontal biomaterial displacement at 2 weeks but not at 6 weeks. Histological analysis showed that sham surgery had a significantly higher percentage of bone area fraction than the DBBM + CM and PLGA + β-TCP at 2 weeks, but not at 6 weeks. Residual biomaterial area fraction showed no significant differences among experimental groups at any healing time. Conclusions: The alloplastic biomaterials showed suitable construct integrity and retention in the defect. All biomaterials were associated with limited new bone formation comparable to the sham surgery control.