Which is the MOST common fungal organism found in the oral cavity?

Candida albicans is the most common oral fungal organism — it is a commensal organism normally present in the oral cavity of 30–60% of healthy individuals. It becomes pathogenic under conditions of immunosuppression (HIV/AIDS, systemic steroids, chemotherapy), xerostomia, antibiotic use, or denture wearing. The other options (Aspergillus, Blastomyces, Cryptococcus, Histoplasma) cause serious systemic fungal infections but are not normal commensals of the oral cavity.