No abstract

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.

The aim of this study was to evaluate the bio-absorption and bone regeneration of human tooth-derived dentin scaffold, entitled as perforated root-demineralized dentin matrix (PR-DDM), after in vivo implantation into the critical-size iliac defects. The dentin scaffolds were prepared from human vital, non-functional teeth. Thirty artificial macro-pores (Ø 1 mm) were added after removing the enamel portion. The modified teeth were supersonically demineralized in 0.34 N HNO3 for 30 min. The microstructure was observed by scanning electron microscope (SEM). The 3D micro-CT and histological analysis were carried out to evaluate the bio-absorption of PR-DDM at 2 and 4 months. A smooth dentin collagen surface with symmetrical macro-pores and tube-type dentinal tubules (Ø 1–2 µm) with micro-cracks were observed on the perforated region. A significant number of custom-made macro-pores disappeared, and the size of the macro-pores became significantly wider at 4 months compared with the 2 months (p < 0.05) evaluated by 3D micro-CT. Histological images revealed the presence of multinucleated giant cells attached to the scalloped border of the PR-DDM. The morphological changes due to bio-absorption by the cellular phagocytes were comparable to the 3D micro-CT and histological images at 2 and 4 months. Altogether, the results demonstrated that the PR-DDM block was gradually absorbed by multinucleated giant cells and regenerated bone. Human PR-DDM might serve as a unique scaffold for extraoral bone regeneration.

Vital tooth-derived demineralized dentin matrix (DDM) has a bone-inductive ability, while non-vital tooth-derived DDM lost it. Acid treatment for dentin provides the increase of surface area, the release of matrix-binding growth factors such as BMPs, and the decrease of the infection risk. Human autograft of vital toothderived DDM was achieved first in Japan 2002, while first bone autograft was noted in Italy 1820. This paper introduced dentin/bone biology and a unique clinical case, combined with two types of non-vital tooth-derived DDM (roots, granules) for lateral bone augmentation. A 63-year-old woman revealed highly atrophic mandible in 2015. Three non-vital teeth were extracted, changed in shape, demineralized in 2% HNO 3 , were rinsed, and were grafted immediately. The CT images at 3 months after the graft showed remarkable lateral augmentation. DDM scaffolds were received to host, and two fixtures were placed into the DDM-augmented bone. The patient was successfully restored with their own DDM scaffolds and implant surgery.

of components is similar (mineral 70%, collagen 20%, body fluid 10% by weight). After demineralization, dentin matrix is mainly composed of predominantly type-I collagen (95%) and non-collagenous proteins including growth factors [13]. Growth factors identified in human dentin included insulin like growth factor I (IGF-I), skeletal growth factor/insulin like growth factor II (IGF-II), and transforming growth factor-β (TGF-β) [14]. Considering these reports, human tooth-derived demineralized dentin matrix (DDM) could be defined as acid-insoluble collagen with bone inducing molecules.The history of a bone-inducing research in dentin began with a report in 1967 that animal derived DDM induced bone formation in the intramuscular pockets [15]. Until now, several dentin studies have reported the osteoinductive potency of DDM and presence of BMP molecule in dentin matrix [16][17][18][19][20]. In addition, it was noted that DDM derived from human teeth, induced bone and cartilage independently in subcutaneous tissues of nude mice at 4 weeks after implantation [20,21]. As human tooth-derived DDM has been recycled as osteoinductive materials for local bone regeneration [20], therefore, this case report described the efficacy of autogenous DDM for bone regeneration in the extracted socket.The aim of this clinical report was to evaluate the feasibility of the autogenous DDM on new bone formation during the healing of the extracted socket after a period of 12 months. The observation of