Calvarial bone defect regeneration using beta-tricalcium phosphate: a translational research study in rat animal model

Abstract

Background: Guided bone regeneration (GBR) using osteoconductive graft materials has been used for osseous defect healing. The aim of this translational research study was to design and test a critical size calvarial defect (CSD) model in rats, to test GBR with beta-tricalcium phosphate (beta-TCP), using histology and micro computed tomography (micro-CT) assessment.Methods: Female Wistar albino rats (n=10) weighing 300 grams and aged 6-weeks were used and full thickness CSD were created in calvaria following exposure under general anesthesia. CSD were randomly divided into two groups for treatment, based on defect filling material: control group (no graft placed in defect; n=5); and beta-TCP group (defect grafted with beta-TCP; n=5). Both defects were covered with collagen membrane. After 8-weeks of healing the animals were sacrificed and calvarial specimens were subjected to micro-CT and histological assessment.Results: Based on micro-CT the new bone volume (NBV) was significantly higher in beta-TCP group (3.48±0.27 mm3; p<0.05), than control group (2.88±0.33 mm3). Similarly, new bone mineral density (NBMD) was significantly higher in beta-TCP group (0.426±0.018 g/mm3; p<0.01), than control group (0.243±0.015 g/mm3). Histology revealed greater new bone bridging the entire defect with interspersed graft particles in the beta-TCP group.Conclusions: Within the limitations of the present study, GBR of rat calvarial CSD with beta-TCP and collagen membrane, results in significantly higher NBV and NBMD, and is a reliable and reproducible translational research model.