MICROBIOLOGIA BUCAL- Biofilme dental

Summary

This video explores the importance of dental plaque (biofilm) in oral health, highlighting its role in dental diseases like cavities and periodontal diseases. It explains the composition of biofilm, its stages of formation, and the bacteria involved, particularly focusing on the differences between supragingival and subgingival plaque. The concept of specific plaque hypotheses is discussed, emphasizing the importance of the bacteria present in the plaque. The video also details the phases of biofilm development, from initial colonization to maturation, and how the biofilm interacts with the oral environment, contributing to oral health and disease.

Takeaways

• 😀 The dental biofilm, also known as bacterial plaque, is crucial in the development of several oral diseases, including dental caries and periodontal diseases.
• 😀 The biofilm is primarily composed of bacteria, with a matrix of polysaccharides, glycoproteins, and ions like calcium and phosphate that help bind the bacteria together.
• 😀 The biofilm can be divided into two categories: supra-gingival (above the gum line) and sub-gingival (below the gum line), each with different bacterial compositions.
• 😀 The theory of specific plaque, developed in 1976, suggests that it is not just the presence of plaque but the types of bacteria within it that determine whether disease will occur.
• 😀 Healthy supragingival plaque is composed mainly of pioneer bacteria such as *Streptococcus oralis* and *Streptococcus sanguinis*, which are typically non-pathogenic.
• 😀 Cariogenic plaque, associated with cavities, is rich in *Streptococcus mutans*, *Streptococcus sobrinus*, and *Lactobacillus*, which produce glucans from sugars like sucrose, leading to acid production and enamel demineralization.
• 😀 Periodontal diseases are linked to subgingival biofilm, which is more complex and involves bacteria such as *Porphyromonas gingivalis* and *Fusobacterium nucleatum*, and is typically associated with poor oral hygiene.
• 😀 In periodontal diseases like gingivitis and periodontitis, the bacterial composition changes, with an increase in gram-negative, anaerobic bacteria, leading to inflammation and tissue damage.
• 😀 The formation of biofilm on dental surfaces follows a process starting with the acquisition of a pellicle (a thin organic layer), which allows bacteria to adhere and begin proliferating.
• 😀 Biofilm maturation involves bacterial aggregation and the formation of microcolonies, where various bacterial species coexist and interact, leading to a dense, structured biofilm matrix with channels for nutrient flow.

Q & A

What is dental biofilm, and why is it important?

Dental biofilm, also known as plaque, is a bacterial aggregate primarily composed of bacteria that adhere to the teeth and other solid structures in the mouth, such as prosthetics. It plays a crucial role in the development of dental diseases, including caries and periodontal diseases.

What are the main components of the intermicrobial matrix in biofilm?

The intermicrobial matrix in biofilm consists mainly of polysaccharides, such as glucans, fructans, and heteropolysaccharides, which are produced by the bacteria themselves. It also contains salivary glycoproteins, proteins, calcium, phosphate, and sodium.

What are the characteristics of supra-gingival plaque?

Supra-gingival plaque is the biofilm that forms above the gum line. It mainly consists of gram-positive, facultative anaerobic bacteria such as Streptococcus oralis, Streptococcus sanguinis, and Actinomyces. It is commonly found in individuals who brush their teeth regularly.

How does the theory of specific plaque hypothesis relate to oral diseases?

The specific plaque hypothesis, proposed in 1976, emphasizes that not all plaque is equally harmful. It suggests that specific bacteria within the plaque, such as *Streptococcus mutans* for caries, are responsible for the development of oral diseases, rather than plaque alone.

What is the difference between supra-gingival and subgingival plaque?

Supra-gingival plaque is located above the gum line, whereas subgingival plaque exists below the gum line, in the periodontal sulcus. Subgingival plaque is more involved in periodontal diseases and contains a higher proportion of anaerobic, gram-negative bacteria.

What role do *Streptococcus mutans* and *Lactobacillus* play in dental caries?

*Streptococcus mutans* and *Lactobacillus* are key bacteria involved in dental caries. They are acidogenic and aciduric, meaning they produce acid from sugars like sucrose and can survive in low pH environments, leading to the demineralization of enamel and the formation of cavities.

What is the relationship between oral hygiene and the formation of plaque?

Good oral hygiene, such as regular tooth brushing, helps prevent plaque accumulation. If plaque is not removed, it can accumulate and lead to gingivitis, periodontal diseases, and caries. Plaque forms continuously, but regular brushing can control its buildup.

How do anaerobic bacteria contribute to periodontal disease?

Anaerobic bacteria, which thrive in low-oxygen environments like subgingival plaque, are major contributors to periodontal disease. Bacteria such as *Porphyromonas gingivalis* and *Fusobacterium nucleatum* are linked to periodontitis, where they cause inflammation and destruction of the periodontal tissues.

What is the process of biofilm formation in the oral cavity?

Biofilm formation begins with the acquisition of a pellicle layer on the tooth surface, which is composed of salivary proteins. The first bacteria to adhere to this pellicle are pioneers, mainly *Streptococcus* species. As these bacteria proliferate, other bacteria join through a process called coagregation, forming a mature biofilm.

How does the presence of specific bacteria in plaque relate to the severity of oral diseases?

The severity of oral diseases is influenced by the types of bacteria present in the plaque. For example, the presence of *Streptococcus mutans* in plaque is closely associated with dental caries, while the presence of *Porphyromonas gingivalis* and other anaerobic bacteria in subgingival plaque is linked to periodontal diseases such as periodontitis.