Dentin is a potential bone graft substitute given that it shares compositional similarity with bone. It remains unknown regarding the mechanism of demineralization levels affecting its osteogenic efficacy in bone regeneration. This study evaluated the osteogenic effects of partially demineralized dentin block (PDDB) and non-demineralized dentin block (NDDB) in alveolar ridge augmentation.

In vitro , human bone marrow mesenchymal stem cells (hBMSCs) were cultured on dentin blocks demineralized with 2 % nitric acid for 0–60 min. ALP activity and osteogenic gene expression were detected by ALP staining and RT-qPCR, respectively. In vivo , six beagles underwent bilateral alveolar ridge splitting technique (ARST) with PDDB or NDDB. Histology was analyzed by hematoxylin-eosin staining, Masson's trichrome staining and immunohistochemistry. Micro-CT examination and Toluidine blue staining were performed 3 months after implant placement.

In vitro , there were significantly increased ALP activity and expression of osteogenic genes in hBMSCs with dentin blocks with 10-min demineralization (all P < 0.05). In vivo , there was no statistical difference in ridge width gain between groups ( P > 0.05). However, the PDDB group exhibited superior bone regeneration based on histological analysis. Furthermore, the PDDB group showed significantly higher RUNX2 and OCN expression, and more vigorous bone regeneration at the implant-dentin graft interface. Additionally, no significant inter-group differences were observed in bone microstructure and quantitative parameters (all P > 0.05).

Dentin blocks are feasible for ARST ridge augmentation, which can boost implant osseointegration. PDDB can further enhance their osteogenic efficacy, offering a favorable option for alveolar bone regeneration clinically.