A Narrative Review on Oral Microbiome Dysbiosis in Benign and Malignant Oral Lesions: Mechanistic Insights and Clinical Implications

Maintaining oral and systemic health depends heavily on the dynamic and varied microbial environment found in the human mouth cavity. There is growing evidence that the oral microbiota plays a role in the pathophysiology of both benign and malignant oral cancers by producing carcinogenic chemicals, modifying host immune responses, and causing chronic inflammation. Malignant tumors like oral squamous cell carcinoma (OSCC) show profound dysbiosis marked by enrichment of pathogenic taxa such as Porphyromonas gingivalis, Prevotella intermedia, and Fusobacterium nucleatum, whereas benign lesions like papillomas, fibromas, and odontogenic tumors show localized microbial alterations. This review examines the molecular processes connecting microbial dysbiosis to carcinogenesis, summarizes current understanding of the oral microbiome across several oral cancers, and emphasizes potential diagnostic, prognostic, and therapeutic applications.