Oral biofilm, commonly known as dental plaque, is a community of microorganisms that naturally forms on surfaces within the mouth. This sticky, colorless deposit is composed of bacteria and other microbes embedded in a protective matrix made of host and bacterial polymers. While a natural occurrence, its accumulation can significantly impact oral health if not managed effectively.
How Oral Biofilms Form
The formation of oral biofilm is a multi-stage process that begins almost immediately after teeth are cleaned. Initially, a thin layer of salivary proteins and other macromolecules, called the acquired pellicle, forms on the tooth surface. This pellicle acts as an adhesive layer for bacterial attachment.
Following pellicle formation, free-floating bacteria in the mouth make initial contact. Early colonizer bacteria, such as Streptococcus and Actinomyces species, then firmly attach to the pellicle, establishing a foundational layer. As these initial colonizers multiply, they secrete an extracellular polymeric substance (EPS), a glue-like matrix composed of polysaccharides, proteins, and nucleic acids.
This extracellular matrix provides a protective shield for the bacteria, enhancing their adherence to each other and to the tooth surface. It also protects the microbial community from mechanical stress and antimicrobial agents. As the biofilm matures, it becomes receptive to other bacterial species, known as late colonizers, leading to a diverse and complex microbial community. This organized structure allows bacteria to thrive and resist removal.
Oral Health Consequences
The accumulation and maturation of oral biofilms can lead to several oral health issues. One common consequence is dental caries, or cavities, which occur when certain bacteria within the biofilm metabolize sugars from food and drinks. This metabolic process produces acids that demineralize tooth enamel, leading to cavities.
Oral biofilms also trigger inflammatory responses, contributing to gum diseases. Gingivitis, an early stage of gum disease, manifests as red, swollen, and sometimes bleeding gums due to biofilm accumulation along the gumline. If gingivitis is left unaddressed, it can progress to periodontitis, a more severe condition.
In periodontitis, the biofilm’s bacterial toxins and the body’s inflammatory response lead to the destruction of tissues and bone supporting the teeth, potentially resulting in tooth loss. Halitosis, or bad breath, is another common consequence, caused by the metabolic activities of microorganisms within the oral biofilm.
Strategies for Control and Prevention
Managing and preventing oral biofilms requires effective oral hygiene practices. Regular and thorough toothbrushing, at least twice daily for two minutes, helps remove biofilm from tooth surfaces. Using a soft-bristled toothbrush and light pressure is recommended to avoid gum injury, with the toothbrush angled at 45 degrees towards the gumline to clean just above and below it.
Daily flossing is equally important for removing biofilm from interdental spaces, areas that toothbrushes often cannot reach effectively. Flossing involves gently guiding the floss between teeth and curving it around each tooth, reaching slightly beneath the gumline. While brushing and flossing are fundamental, mechanical methods alone may not be sufficient for complete biofilm control.
Antimicrobial mouthwashes can supplement mechanical cleaning by suppressing bacterial adhesion during the early stages of biofilm formation. Mouthwashes containing active agents like chlorhexidine gluconate (CHX) or essential oils have demonstrated effectiveness in reducing biofilm accumulation and gingivitis. However, mouthwashes are not typically aimed at mature biofilms and are best used as an adjunct to brushing and flossing.
Professional dental cleanings, often referred to as scaling and root planing, are an important component of prevention and treatment. Dental hygienists use specialized instruments to remove hardened plaque, known as tartar or calculus, and disrupt mature biofilms that cannot be removed by daily home care. These professional cleanings, typically recommended every six months, help maintain a balanced oral microbiome and reduce the risk of dental issues.