Quantification of Stem Cells in Healthy Pulp and Periodontal Tissues: A Systematic Review

Dental pulp and periodontal tissues are critical components of the oral cavity, harboring distinct populations of stem cells with immense potential for regenerative medicine. Dental pulp stem cells (DPSCs) and periodontal ligament stem cells (PDLSCs) are the most well-characterized mesenchymal stem cells (MSCs) derived from these tissues, exhibiting multipotency, self-renewal capacity, and immunomodulatory properties. Accurate quantification of stem cell abundance and characterization of their phenotypic profiles are essential for optimizing their clinical application in tissue repair and regeneration. This systematic review summarizes the current state of knowledge regarding the quantification of stem cells in healthy dental pulp and periodontal tissues, focusing on the use of stem cell biomarkers, analytical methods, and key findings from clinical and preclinical studies. We systematically synthesize data from 50+ peer-reviewed studies to compare stem cell density, biomarker expression patterns, and functional heterogeneity between these two tissues. Our analysis confirms that healthy young dental pulp is a more abundant reservoir of functional stem cells than periodontal tissues, as evidenced by significantly higher expression levels of classic MSC markers (CD44, CD133, vimentin), lineage-specific markers (CD24), and repair-related markers (COX-2) in dental pulp. Pan-cytokeratins (pan-CK), an epithelial cell marker, shows consistent strong expression in both tissues, reflecting their shared epithelial components. We also discuss the limitations of current quantification methods, including variability in biomarker selection, sample heterogeneity, and analytical techniques, and highlight future directions for standardizing stem cell quantification protocols. This review provides a comprehensive overview of the field, supporting the clinical utility of DPSCs for pulp capping, oral tissue repair, and systemic regenerative therapies.