Microbiology and biofilms
Dental plaque is a structured microbial biofilm. Disease reflects the interaction of microbes, substrate, host and environment rather than one organism alone.
Understand
Biofilm organisms interact with one another and with the host. Ecological change under frequent sugar or persistent inflammation favours disease; the presence of one species alone rarely explains the whole picture.
Assess
Ask about plaque-control access, diet, saliva, restorations and host factors. Distinguish colonisation from an invasive infection with clinical signs, spread and systemic response.
Apply
Mechanical disruption and modification of the environment are central. Antimicrobials may have defined roles, but they do not replace drainage, source control or daily biofilm control.
Key distinctions
In caries, repeated fermentable carbohydrate exposure selects an acid-tolerant community rather than a single “caries germ”. In periodontitis, dysbiosis and a susceptible host drive destructive inflammation. This ecological model explains why removing a biofilm mechanically and altering its environment are more durable than relying on a short antimicrobial course alone.
Think through a case
A patient improves briefly on antibiotics but the offending tooth remains untreated. The biofilm and source can persist, so the symptoms recur when medication stops.
The distinction to remember
Do not equate a positive microbial finding with causation in isolation. Clinical signs, host response and anatomy are needed to identify invasive disease.
Test your recall
Why is mechanical plaque disruption central to prevention?
Show answer
A biofilm resists clearance and can re-establish after antimicrobial exposure.