Dental Stem Cells: Novel Advances in Regenerative Dentistry

Stem cell research has opened new possibilities for regenerative medicine, including dentistry. Dental stem cells can repair damaged tissues, regenerate lost structures, and contribute to systemic treatments beyond oral health. Their accessibility from extracted teeth and minimally invasive collection methods make them an attractive option for therapeutic applications.

Advances in research have improved understanding of how these cells function in tissue regeneration. Scientists are working to optimize their isolation, culture, and differentiation to enhance clinical outcomes.

Types Of Dental Stem Cells

Dental stem cells originate from different dental structures, each with unique biological properties. Among the most studied are dental pulp stem cells (DPSCs), which come from the pulp tissue of permanent teeth. These cells have a high proliferative capacity and multilineage differentiation potential, making them suitable for tissue engineering. DPSCs can differentiate into odontoblast-like cells for dentin regeneration and also exhibit neurogenic and angiogenic properties (Gronthos et al., 2000, Proceedings of the National Academy of Sciences).

Stem cells from human exfoliated deciduous teeth (SHED) share similarities with DPSCs but originate from primary teeth. They have a more immature phenotype and greater plasticity, allowing differentiation into various cell types, including osteoblasts, adipocytes, and neuronal-like cells (Miura et al., 2003, Proceedings of the National Academy of Sciences). Their higher proliferation rate makes them attractive for regenerative therapies requiring rapid cell expansion.

Periodontal ligament stem cells (PDLSCs) reside in the periodontal ligament and contribute to periodontal homeostasis. They can regenerate cementum, periodontal ligament fibers, and alveolar bone, making them a focus for periodontal disease treatment and tooth-supporting structure regeneration (Seo et al., 2004, The Lancet). Their ability to modulate inflammation further enhances their therapeutic potential.

Stem cells from the apical papilla (SCAP) are found in the developing root apex of immature permanent teeth. These cells have a high proliferative rate and strong odontogenic differentiation potential, making them relevant for regenerative endodontic procedures (Sonoyama et al., 2006, Journal of Dental Research). Their ability to generate odontoblast-like cells and contribute to root elongation makes them valuable in endodontic therapies.

Dental follicle progenitor cells (DFPCs) originate from the dental follicle, an ectomesenchymal tissue surrounding the developing tooth germ. They can differentiate into cementoblasts, osteoblasts, and fibroblasts, playing a role in periodontal tissue engineering (Morsczeck et al., 2005, Cell and Tissue Research). Their involvement in tooth eruption and periodontal development highlights their significance in craniofacial regenerative strategies.

Isolation And Culture Methods

Obtaining viable dental stem cells requires precise techniques to preserve their regenerative potential. The process begins with the careful extraction of dental tissues from exfoliated deciduous teeth, impacted third molars, or periodontal tissues. Extracted teeth are immediately placed in sterile transport media such as Hank’s Balanced Salt Solution (HBSS) or Dulbecco’s Modified Eagle Medium (DMEM) with antibiotics to prevent contamination and maintain viability. Prolonged exposure to non-optimized conditions can compromise cell viability and reduce proliferation rates (Bakopoulou et al., 2011, Journal of Endodontics).

In the laboratory, dental tissues undergo enzymatic or mechanical dissociation to isolate stem cells. Enzymatic digestion with collagenase type I or a collagenase-dispase combination yields a higher number of viable cells compared to mechanical dissociation, which involves mincing tissues and culturing them in growth media (Zhang et al., 2006, Stem Cells and Development). However, excessive enzyme exposure can damage surface markers, requiring careful optimization of digestion time and concentration.

Cultured cells are expanded in specialized media such as Alpha Minimum Essential Medium (α-MEM) or DMEM supplemented with fetal bovine serum (FBS), L-glutamine, and antibiotics. Hypoxic conditions (2–5% O₂) enhance proliferation and preserve multipotency (Yamamoto et al., 2014, Tissue Engineering Part A). Subculturing occurs at 80% confluence, with enzymatic detachment using trypsin-EDTA to minimize stress.

To refine stem cell populations, researchers use fluorescence-activated cell sorting (FACS) or magnetic-activated cell sorting (MACS) based on surface markers like STRO-1, CD90, CD105, and CD146 (Shi et al., 2005, Journal of Bone and Mineral Research). Enriching for these markers improves consistency for experimental and therapeutic applications. Additionally, three-dimensional (3D) culture systems, such as spheroid formation or scaffold-based approaches, better mimic the native microenvironment and enhance differentiation potential (Rosa et al., 2016, Journal of Dental Research).

Molecular And Cellular Characteristics

Dental stem cells exhibit a molecular profile that underpins their regenerative capabilities. They express core stemness-associated genes such as NANOG, OCT4, and SOX2, which contribute to self-renewal and multilineage differentiation (Nakamura et al., 2009, Stem Cells). Their mesenchymal origin is confirmed by the presence of CD73, CD90, and CD105 and the absence of hematopoietic markers like CD34 and CD45.

These cells rely on glycolytic metabolism rather than oxidative phosphorylation, allowing them to adapt to hypoxic environments in damaged tissues (Murray et al., 2014, Stem Cell Research & Therapy). This metabolic flexibility supports survival and proliferation under stress. As differentiation progresses, a shift toward oxidative phosphorylation signals lineage commitment and functional maturation.

The extracellular matrix (ECM) surrounding dental stem cells provides structural support and biochemical cues that guide differentiation. Key ECM components such as fibronectin, laminin, and type I collagen interact with integrin receptors, activating pathways that regulate adhesion, migration, and differentiation (Gronthos et al., 2002, Journal of Cell Science). Matrix metalloproteinases (MMPs) secreted by these cells facilitate ECM remodeling, essential for tissue regeneration.

Extracellular Vesicle Production And Composition

Dental stem cells secrete extracellular vesicles (EVs) that mediate tissue repair and cellular communication. These vesicles include exosomes (30–150 nm) and microvesicles (100–1000 nm), which originate from endosomal and plasma membrane pathways. Their cargo—proteins, lipids, mRNA, and microRNA (miRNA)—influences recipient cell behavior.

Proteomic analysis of EVs from dental stem cells has identified proteins involved in extracellular matrix remodeling, angiogenesis, and cell proliferation. Growth factors such as vascular endothelial growth factor (VEGF), transforming growth factor-beta (TGF-β), and insulin-like growth factor-1 (IGF-1) promote vascularization and tissue repair. Additionally, EVs contain signaling molecules like Wnt and Notch pathway regulators, which guide stem cell differentiation and tissue homeostasis. Their lipid composition, including sphingolipids and phosphatidylserine, enhances membrane fusion and cargo delivery.

Differentiation Mechanisms

Dental stem cells differentiate into multiple cell lineages based on intrinsic genetic programs, extracellular signals, and microenvironmental factors. This process involves transcription factors, epigenetic modifications, and biochemical cues that drive lineage commitment.

Odontogenic differentiation is a primary pathway, particularly for pulp and apical papilla-derived cells. Bone morphogenetic proteins (BMPs), transforming growth factor-beta (TGF-β), and Wnt signaling activate odontoblast-specific genes like DSPP and DMP1, promoting dentin-like structure formation. Biomimetic scaffolds enriched with hydroxyapatite or calcium phosphate enhance differentiation, mimicking the native dentin environment. Mechanical stimulation and substrate stiffness also influence differentiation, with stiffer matrices favoring odontogenic commitment through mechanotransduction pathways that activate Runx2.

These cells also exhibit neurogenic potential, making them candidates for neural tissue repair. Neurotrophic factors like brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) induce neuronal marker expression, including βIII-tubulin and NeuN. Co-culture with neural cells or exposure to retinoic acid enhances differentiation, resulting in cells with axon-like projections and electrophysiological properties. This neurogenic potential has spurred interest in using dental stem cells for treating neurodegenerative conditions, with early studies suggesting their role in neuroprotection and axonal regeneration.