**8. Dentin scaffolds**

 DDM is defined as an acid-insoluble dentin collagen with natural cross-links and is a cell-free absorbable biomatrix with dentinal tube structure. DDM from autogenous tooth can be applied for bone grafts and tissue engineering as its own biomaterial, thus allowing improvement of bone induction while reducing the risk of infection. Human DDM can be recycled as cross-linked collagen in familial graft and allograft, because DDM is a cell-free matrix without antigenicity. We published bone regeneration in sheep iliac bone defect by human DDM root-type scaffold or β-TCP block [2, 54] (**Figure 4**). Bovine- and pig-derived collagenous materials are available as medical devices for the human body all over the world.

**Figure 4.**  *Human DDM scaffold in sheep iliac bone defect at 2 months (HE).* 
