Abstract
In the present study, gelatin/calcium phosphate pastes with different degradation rates of gelatin were prepared and evaluated for the bone response after implantation into a subperiosteal pocket of rat calvaria. Four types of gelatin with different sizes and degrees of cross-linking were prepared: Sample A: smaller size and lower degree of cross-linking; Sample B: smaller size and higher degree of cross-linking; Sample C: larger size and lower degree of cross-linking; and Sample D: larger size and higher degree of cross-linking. A powder mixture of each gelatin with calcium phosphate was mixed with a liquid. Then, the mixed paste was placed into a polytetrafluoroethylene (PTFE) tube, which was implanted directly into a subperiosteal pocket of rat calvaria. At 8 weeks after implantation, each specimen was excised, and non-decalcified thin sections were prepared. After staining each section with toluidine blue, the bone response was observed histologically and histomorphometrically. New bone formation was observed from the calvaria surface, not from the periosteum for the four different gelatin/CaP paste samples. Significantly greater amounts of residual non-degraded gelatin was observed for Sample B/CaP and Sample D/CaP paste (p<0.05). It was revealed that Sample C/CaP paste with a lower degree of gelatin cross-linking produced greater amounts of new bone formation. The size of gelatin also influenced bone formation. Gelatin/CaP paste is advantageous because it can be applied to any shape of defect, and it is a promising material for bone regenerative treatment.
