A Single-Nucleus Transcriptomic Atlas of Human Supernumerary Tooth Pulp Reveals Lineage Diversity and Transcriptional Heterogeneity Using PCA-Based Analysis

(1) Background: Supernumerary teeth are developmental anomalies, and their pulp tissue may harbor unique cellular and molecular features. However, the biology of this rare tissue remains poorly understood. This study aimed to characterize the cellular diversity and regenerative potential of supernumerary pulp at single-nucleus resolution. (2) Methods: Human supernumerary tooth pulp samples were analyzed using single-nucleus RNA sequencing. Gene expression profiles were processed and reduced to their main patterns of variation using principal component analysis (PCA), supported by clustering, pathway analysis, and lineage-specific scoring. (3) Results: The analysis suggested two dominant biological programs: a vascular–immune/stress axis and an extracellular matrix (ECM)/contractile remodeling axis. Vascular lineages were closely linked to immune and stress responses, while mesenchymal and perivascular populations were enriched in ECM-related pathways. Neural and glial contributions were relatively minor. (4) Conclusions: These findings suggest that supernumerary pulp appears to preserve key regenerative features similar to normal pulp, but with potential reinforcement of vascular–immune coupling and ECM remodeling. This work represents the first single-nucleus transcriptomic reference for supernumerary pulp, offering a foundation for future studies on dental pulp regeneration.