Biofilm formation is a survival strategy for bacteria, as it gives them the capability for adaptation, communication and resistance.

Oral biofilm formation

Biofilm formation is a survival strategy for bacteria, as it gives them the capability for adaptation, communication and resistance.

Oral biofilm has pathogenic potential and its presence is associated with the development of caries, gingivitis, periodontal disease, peri-implant mucositis and peri-implantitis.

Diagram of dental biofilm structure.The process of oral biofilm formation follows a colonisation pattern referred to as autogenic succession, in which microorganisms themselves induce local physical and chemical changes, which, in turn, alter the bacterial plaque. Bacterial colonisation initiates with the formation of a salivary protein pellicle (albumin, glycoproteins, acidic proline-rich proteins, mucin, etc.) on tooth enamel, to which, gram-positive bacilli and cocci adhere by specificity, including S. sanguis, S. orallis, S. mitis and A. viscosus, resulting in primary colonisation.

After the primary colonisers adhere and multiply, Fusobacterium nucleatum seems to act as a coaggregation bridge between primary colonisers and other late colonising microbial species.

As plaque increases in thickness, oxygen concentration in the deepest areas reduces, and so aerobic bacteria begin to disappear from this area, to be replaced by others, whose redox potential is lower. Therefore, aerobic organisms are located in the most superficial areas of the oral biofilm, strict anaerobes or less aerotolerant species in the deepest areas, and the streptococci anywhere therein.

Evolution of Dental Biofilm Formation