Composition of saliva and acquired pellicle Flashcards
What are the immune and non-immune defense mechanisms of saliva?
- Protection
- Buffering
- Pellicle formation
- Maintenance of tooth integrity
- Antimicrobial action
- Digestion
- Taste
Briefly describe the constituents of saliva
99.5% water and 0.5% electrolytes
Contains the following proteins:
- Enzymes
- Lysozymes
- Defensins
- Mucins
- Histatins
- Statherin
- Lactoferrin
- Small organic molecules
Name some enzymes in saliva
‣ amylase, peroxidase, and salivary lipase
What are defensins?
proteins of the immune system
‣ Assist in killing phagocytosed microbes by forming pores in membrane to efflux essential nutrients
What are mucins and what do they do?
glycosylated proteins produced by epithelial tissues.
‣ Produced by the mucous acinus
‣ They form gel secretions so serve provide lubrication
‣ Protection in oral cavity
‣ Cell signalling
‣ Form chemical barriers – over enamel(pellicle)/mucosa
‣ Aggregation of bacteria
‣ Overexpression of mucin proteins (MUC1) can be associated with cancers e.g. adenocarcinomas and lung diseases
What are histatins?
antimicrobial peptides in the oral cavity
‣ Histatin 1 and histatin 2 = wound-closing factors in saliva – enhance initial epithelial cell migration
‣ Secreted by Von Ebners’ glands (minor glands)
‣ Encoded for by 2 genes: HTN1, HTN3
What does statherin do?
Prevents calcium-phosphate precipitation in saliva, maintaining high Ca2+ level in saliva for remineralsation/ PO43- for buffering
‣ STATH gene ‣ SIgA (secretory IgA) – antibody in mucous secretions
‣ Tears saliva GIT, respiratory epithelium
What does lactoferrin do?
Antimicrobial globular glycoprotein in secretory fluids
‣ Binding and transport of iron ions
‣ Binds to bacterial cell walls, affecting permeability and causing lysis ‣ Binds to viral proteins and stops penetration into cell/ replication
‣ Also anti-fungal and anticarcinogenic
Give examples of small organic molecules in saliva
Glucose, urea, lipids, amino acids
What is the dental pellicle and when does it form?
Dental pellicle is a protein film that forms on the surface enamel by selective binding of glycoproteins from saliva that prevents continuous deposition of salivary calcium phosphate.
It forms seconds after a tooth is cleaned
What does the acquired pellicle protect the tooth from?
It is also protective to the tooth from the acids produced by oral microorganisms after consuming the available carbohydrates
What does chlorohexidine do?
Chlorhexidine prevents adhesion of calculus to the tooth
What are some of the components of the acquired pellicle?
macromolecules such as lysozyme, alpha-amylase, perioxidase, immunoglobulin A, immunoglobulin G, glycosyltransferase, proline-rich proteins, mucins, albumin and breakdown products from macromolecules from both saliva and bacteria
What is ‘plaque’ and what does it contribute to?
Plaque is an adherent microbial biofilm attached to teeth and the primary aetiological agent of dental caries and periodontal disease. 1000-25000 species involved in plaque.
• The microbial composition reflects the site of formation and the host diet