Oral Biofilms in Health and Disease 2025

Biofilms are surface-associated microbial communities enclosed in a protective extracellular matrix that helps microorganisms survive harsh environments, cooperate in nutrient use, and tolerate antimicrobial treatments. This resistance is so essential that it is now considered a defining feature of medically relevant biofilms.

The protective nature of biofilms has been recognized since the early days of microbiology. In the 17th century, Antonie van Leeuwenhoek observed that antimicrobial rinses killed only surface microbes in dental plaque, leaving deeper ones unharmed. Modern studies confirm this, showing that some oral bacteria are shielded within biofilms by polymers produced by neighboring species.

Oral biofilms are especially complex and polymicrobial, involving bacteria and eukaryotes interacting on hard and soft surfaces. Research on dental caries and periodontal disease has been central to understanding polymicrobial interactions and microbial ecology, making oral biofilms key model systems.

An imbalance in the oral microbiome, known as dysbiosis, is linked not only to oral diseases but also to systemic conditions such as cardiovascular disease, diabetes, inflammation, and neurodegenerative disorders. These findings highlight the broader importance of the oral microbiome in overall health.

Oral microbiology has also advanced knowledge of microbial communication, virulence regulation, spatial organization, and biofilm matrix structure. Today, oral biofilms are seen as dynamic, functional communities whose interactions shape both health and disease.