OE L23 Gingival Crevicular Fluid Flashcards
What is gingival crevicular fluid?
Fluid derived from underlying periodontal tissues which gathers at the gingival crevice. Distinct from saliva.
How can GCF be collected?
- Capillary tubes
- Filter strips
- Gingival washing
How is GCF regarded in health vs in diseased states?
GCF in health = transudate
GCF in disease = exudate
What is flow rate of GCF determined by?
GCF flow rate is proportional to the degree of gingival inflammation.
Healthy = low rate
Inflamed = high rate
What are the constituents of GCF derived from?
- Plasma
- Interstitial fluid
- Microbial dental plaque
- Host inflammatory cells
- Host tissue cells (fibroblasts)
What is the transudate caused by?
Distrubances in hydrostatic or colloid osmotic pressure- not by inflammation.
What is the average flow rate of transudate?
0.05-0.2 ul per min
What pressures can increase flow of GCF?
- Mastication
- Tooth brushing
Only cause small increases in flow.
How does fluid pass from the sulcus to the crevice?
Intercellular routes across the wall of the gingival epithelium. Movement is beleived to be osmotic mediated.
GCF flow in health is determined by what 5 factors?
- Passage of interstitial fluid from capillaries to gingival tissues
- Removal of fluid by lymphatic system
- Filtration coefficient of junctional and sulcular epithlium
- Differences in osmotic pressure (created by presence of plaque products within sulcus)
- Differences in hydrostatic pressure of interstitial fluid and sulcular fluid e.g. from brushing or mastication
How does the microbial population affect GCF?
Microbial population in the gingival crevice could produce products which create an osmotic flow of liquid into the sulcus, in order to dilute the presence of such products.
Effectively pushes them out and into the oral cavity.
How does gingival inflammation cause exudate production?
- Higher levels of plaque create greater osmotic gradient
- Fluid flow rate increased
- Loosening of epithelial cells in gingival epithelium, BM breakdown due to action of inflammatory cells, fluid flows across more easily
- Capillaries become fenestrated due to host immune response and increases hydrostatic pressure
- Fenestrated capillaries allow increased inflammatory cells in tissues
Describe the composition of GCF.
- Derived from interstitial fluid of underlying periodontal tissues
- Greater amount of inorganic components compared to saliva e.g. Na, Ca, P
What are the main functions of GCF?
- Protection of teeth and gingival tissues by washing away potentially harmful bacterial products away from the gingival sulcus
- Contains anitbacterial substances
- High calcium concentration allows pellicle proteins to bind to tooth surface (semi-permeable barrier between enamel and bacteria)
What are the negative consequences of high Ca content of GCF?
- Enhances salivary protein precipitation which could allow increased attachement of bacteria
- Calculus formation: mineralisation of dental plaque, will be particularly damaging if present subgingivally