Plaque Formation and Composition
- Dental plaque is a biofilm that attaches to tooth surfaces, restorations, and prosthetic appliances if left undisturbed.
- An acquired pellicle is a layer of saliva that forms shortly after cleaning the teeth or exposure of new teeth.
- Bacteria attach to the pellicle layer, form micro-colonies, and mature on the tooth, leading to oral diseases.
- Biofilm formation involves six steps, including pellicle formation, bacterial attachment, micro-colony formation, maturation, detachment, and reattachment.
- Different types of bacteria and immune cells are present in the mouth and contribute to oral health.
- Approximately 80-90% of plaque's weight is water, while bacteria make up 70% of the dry weight.
- The remaining 30% consists of polysaccharides and glycoproteins.
- Polysaccharides and glycoproteins contribute to the structure and adhesion of plaque.
- The composition of plaque can vary based on location in the mouth and individual factors.

Bacteria and Biofilm
- Streptococcus mutans and other anaerobes are the main microorganisms that form the biofilm.
- S. mutans uses sucrose to produce a sticky polysaccharide that allows bacteria to cohere, forming plaque.
- Failure to remove plaque allows bacteria to proliferate and cause dental diseases.
- The bacterial composition of plaque changes during different stages of formation.
- Early biofilm primarily consists of Gram-positive cocci, while older biofilm contains more complex flora with rods and filamentous forms.
- Dental plaque is considered a biofilm adhered to the tooth surface.
- It is a microbial community organised to a specific structure and function.
- Plaque is rich in species, with approximately 1000 different bacterial species identified.
- Salivary pellicles act as an adhesive, allowing bacteria to attach and grow on the tooth surface.
- Early colonizers pave the way for late colonizers, leading to the formation of a mature biofilm.

Supragingival and Subgingival Biofilm
- Supragingival biofilm forms above the gums and is the first type of plaque to form after brushing.
- It consists mainly of aerobic bacteria but can develop anaerobic bacteria if not removed.
- Subgingival biofilm is located under the gums and is mostly composed of anaerobic bacteria.
- It forms when supragingival biofilm grows downward into the gum pockets.
- The extracellular matrix of biofilms contains proteins, polysaccharides, and lipids.

Consequences of Plaque Build-up
Gingivitis:
- Inflammatory lesion localised to the gingival tissue
- Result of plaque build-up around the gingival tissues
- Bacteria in biofilm elicit a host response, causing localised inflammation
- Cardinal signs of inflammation include red, puffy gums and bleeding
- Reversible with plaque removal, but can progress to periodontitis if left untreated

Periodontitis:
- Infection of the gums leading to bone destruction around the teeth
- Occurs after gingivitis, not all individuals with gingivitis develop periodontitis
- Plaque accumulation is vital for progression, as bacteria release enzymes that attack bone
- Treatment includes strict oral hygiene and surgical debridement by a dental professional
- Can contribute to systemic diseases and conditions when bacteria spread through the body

Caries:
- Infectious disease caused by bacteria, primarily Streptococcus mutans
- Acid demineralization of enamel, leading to breakdown of inner dental tissue
- Susceptibility depends on individual risk factors and preventive factors
- Factors include low fluoride exposure, sugar consumption, tooth cleaning, and saliva flow
- Organic acids released from plaque cause demineralization and tooth decay

Detection, Treatments, and Related Topics
- Two main methods of detecting plaque build-up: plaque disclosing gel and visual/tactile detection
- Mouthwash with alcohol may not be the best option for controlling plaque accumulation
- Essential oil mouthwashes have been developed as an alternative
- Research on their effectiveness is ongoing, with mixed results
- Lemongrass essential oil mouthwash shows antimicrobial properties as a substitute for alcohol
- Mouthwash containing essential oils and ethyl lauroyl arginate has been found to inhibit plaque and gingivitis
- The canine and feline oral microbiomes have been investigated, revealing insights into the microbial composition
- Flossing is an important part of oral hygiene for removing plaque and preventing dental diseases
- Gingiva, dental disease, and oral microbiology are related topics that contribute to understanding plaque formation and identification