Evaluation of perforated demineralized dentin scaffold on bone regeneration in critical‐size sheep iliac defects

Objectives Regenerating critical‐size bone injury is a major problem that continues to inspire the design of new graft materials. Therefore, tissue engineering has become a novel approach for targeting bone regeneration applications. Human teeth are a rich source of stem cells, matrix, trace metal ions, and growth factors. A vital tooth‐derived demineralized dentin matrix is acid‐insoluble and composed of cross‐linked collagen with growth factors. In this study, we recycled human non‐functional tooth into a unique geometric dentin scaffold, entitled perforated root‐demineralized dentin matrix (PR‐DDM). The aim of this study was to evaluate the feasibility of PR‐DDM as the scaffold for regenerating bone in critical‐size iliac defects. Material and methods Artificial macro‐pores (1 mm in diameter) were added to human vital wisdom tooth after removing the enamel and pulp portions. The modified tooth was demineralized in 0.34 N HNO3 for 30 min and is referred to as PR‐DDM scaffold. Critical‐size defect (10 mm × 15 mm × 9 mm Ø) was created in the iliac crest of six adult sheep. The in vivo bone regeneration by the scaffold was evaluated by micro‐CT, 3D micro‐CT, and histological examination at 2 and 4 months post‐implantation. Results PR‐DDM exhibited better bone ingrowth, especially in the artificial macro‐pores. The results of micro‐CT and 3D micro‐CT revealed good union between scaffold and native bone. New bone formation was observed in almost all portions of PR‐DDM. Higher bone volume inside the scaffold was detected at 4 months compared with 2 months. New bone ingrowth was ankylosed with PR‐DDM, and both osteoinduction and osteoconduction capability of PR‐DDM were confirmed histologically. The ratio of new bone formation was higher at 4 months compared with 2 months by histomorphometric analysis. Conclusions Altogether, these results demonstrated that the human tooth‐derived graft material with a unique geometric structure, PR‐DDM, contributed to active bone ingrowth in critical‐size bone defects. This novel scaffold may have great utility in the near‐future clinical application.