The rise and evolving role of subspecies.

This review examines the classification, distribution, and detection methods of subspecies, focusing on their distinct roles in health and disease. The evolution of classification is traced from early to modern protein-based and genomic methods, such as 16S rRNA and next generation sequencing and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). The review highlights the importance of distinguishing subspecies due to their varying pathogenic potentials and ecological niches in both oral and extraoral environments. Different subspecies exhibit distinct prevalence and activity levels in specific clinical conditions, such as periodontitis and oral squamous cell carcinoma (OSCC). This highlights the importance of accurately identifying subspecies to understand their role in disease progression. Moreover, understanding the varying pathogenic potential of subspecies, which is driven by genetic diversity and virulence factors, is also essential for advancing research and improving patient outcomes.