Comparative analysis of the osteogenic potential of long-term dry-stored deciduous and fresh permanent tooth-derived dentin matrix

Autologous tooth-derived grafts are increasingly being investigated for bone regeneration, as dentin shares with bone a mineral phase and an organic matrix rich in type I collagen and non-collagenous proteins. Deciduous teeth are particularly attractive as biomaterials because they are easily obtained after physiological exfoliation, without additional surgical harvesting or donor-site morbidity and may expose a protein-rich matrix after processing. Whether deciduous teeth retain a biologic advantage after prolonged dry storage remains poorly documented. This proof-of-concept ex vivo and in vitro study compared pooled deciduous teeth from six different donors (exfoliated at least 10 years before the experiment and stored dry at room temperature conditions) with six freshly extracted third molars. The teeth were ground using a dedicated device, and conditioned supernatants were collected at 72 h (T1) and 28 days (T2). Osteocalcin, osteonectin, and BMP-2 were quantified by ELISA, and T1 supernatants were applied to human primary osteoblasts to assess the osteogenic response using qRT-PCR and immunofluorescence. Deciduous teeth-conditioned supernatants showed higher osteocalcin and osteonectin release than permanent teeth at both time points, whereas BMP-2 levels were comparable, though with higher values in deciduous samples. In osteoblasts, deciduous teeth-conditioned supernatants induced enhanced osteogenic responses, including greater activation of Collagen I, Osterix, RUNX-2, Osteocalcin, BMP-2 genes, and higher expression of bone-related proteins. Within the limits of this exploratory study, dry-stored deciduous teeth preserved a biologically active dentin matrix and showed a more favorable osteogenic profile than freshly extracted permanent teeth, supporting further investigation into standardized storage protocols and their potential use in regenerative applications.