Culture-Based Microbiological Assessment of Dentin Biomaterials Prepared from Long-Term Refrigerated Human Teeth: A Pilot Study Toward Evidence-Based Tooth Banking.

Dentin derived from extracted human teeth has emerged as a promising autogenous biomaterial for bone regeneration owing to its structural and biological similarity to bone tissue. Growing clinical interest in dentin-derived graft materials has also stimulated the development of tooth-banking concepts, in which extracted teeth are preserved for future regenerative applications. However, microbiological contamination remains one of the principal concerns associated with long-term storage before clinical use. This in vitro study evaluated the microbiological status of dentin biomaterials prepared from human teeth stored under long-term refrigerated conditions (approximately 4 °C) and subsequently processed using three commercially available dentin-processing systems: BonMaker (BM), Tooth Transformer (TT), and Smart Dentin Grinder (SDG). A total of 72 extracted teeth collected between 2018 and 2025 were allocated to experimental groups and processed into 24 pooled dentin samples. Five freshly extracted teeth served as controls. Culture-based microbiological assessment was performed before and after dentin processing using Schaedler Broth K3 culture media under aerobic and anaerobic conditions. Microorganisms isolated from positive cultures were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Baseline microbiological assessment detected bacterial contamination in 2 of 24 pooled dentin samples (8.3%) and in 4 of 5 control teeth (80.0%). The identified microorganisms included