The fluid present in gingival sulcus, is termed as gingival crevicular fluid or sulcular fluid. In case of healthy gingiva, the flow of GCF is minimal to absent, but it increases during inflammation.
Need for GCF collection and analysis:
GCF is an inflammatory exudate and amount of GCF increases with inflammation.
Collection of GCF being a non-invasive and simple procedure, is especially beneficial in:
- Determining the severity of gingival disease.
- To check the effectiveness of periodontal therapy.
- In monitoring the response of periodontium to the periodontal therapy and to the placement of restorations and prosthetic appliances
- To see the relationship between GCF and systemic disease.
Difficulties that can be encountered during GCF collection:
- Extremely small amount of GCF is present.
- Fluid flow during collection.
- Contamination by saliva can occur.
Methods of collection of GCF:
a) Collection of GCF by using absorbing paper strips:
- Brill technique: in this, the filter paper strip is placed into the sulcus until resistance is felt. It is also known as intra-sulcular method. This method causes some amount of irritation of the sulcular epithelium, thus it itself may cause some fluid flow.
- Loe and Holm-pedersen technique: in this, the filter paper strip is placed ether over the pocket entrance or just at the entrance of the pocket. It is also known as extra-sulcular method. In this the filter paper doesnot come in contact with the sulcular epithelium.
b) Collection of GCF by using pre-weighed twisted threads:
This technique was used by Weinstein et al. In this the threads are placed around the tooth in the gingival crevice.
c) Collection of GCF by using micropipettes:
- In this technique the micropipettes are used, which are of standardized length and diameter.
- These micropipettes are placed inside the pocket and they collects the fluid by capillary action.
d) Collection of GCF by using crevicular washings:
- Crevicular washings can also be used to study GCF.
- This technique involves ejection and then re-aspiration of a known amount of solution in the gingival crevice. Two methods can be used for this,
Oppenheim method (1970):
Takamori designed an appliance initially in 1963, which was later modified by Oppenheim in 1970. This method uses an individual acrylic appliance, which covers the maxilla with soft borders and a groove following the gingival margins. Four collection tubes are connected to this appliance. A peristaltic pump is used to rinse the crevicular area from one side to the other and then crevicular washings are obtained.
Skapski and lehner method (1976):
This method uses two injection needles. One needle is fitted within the other. The inside (ejection) needle lies at the bottom of the pocket, and the outside (collecting) needle lies at the gingival margin. A continuous suction is used to drain the collecting needle into a sample tube. The area is isolated with cotton rolls, then 10 µl of Hankâ€™s solution is ejected and re-aspirated 12 times by re-setting the point of needle at 50µl.
Other methods of GCF collection include,
- Collection of GCF by using platinum loops.
- Collection of GCF by using plastic strips.
- Collection of GCF by using paper points.
Estimation of amount of GCF:
The amount of GCF collected on periopaper can be measured by various means:
a) By weighting the absorbent medium:
The amount of GCF collected on pre-weighed twisted threads can be measured by weighing the sample thread after GCF collection on it. As we already know the initial weight of the thread, we can easily estimate the amount of GCF collected. According to Cimasoniâ€™s measurements: 1.5 mm wide strip of paper, inserted 1 mm into the gingival sulcus of a slightly inflamed gingiva absorbs approximately 0.1 mg of GCF in 3 minutes.
b) By measuring capillary fill of micro-pipettes:
The amount of GCF collected by micro-pipettes can also be easily measured, as the capillary tubes used are of standardized length and diameter.
c) By measuring volume of crevicular washings:
The amount of GCF collected by crevicular washings can also be estimated with ease because in this method we use an already known amount of solution for ejection into the gingival crevice, and then the re-aspirated fluid can be measured.
d) By staining with ninhydrin:
The wetted area with GCF, becomes more visible by staining with ninhydrin which can be then measured planimetrically on an enlarged photograph or with a microscope or a magnifying glass.
e) Electronic method:
The method measures the amount of GCF collected on periopaper by using an electronic transducer (Periotron, Winnipeg, Manitoba). This method is based on the fact, that the flow of electronic current is affected by the wetness of the paper strip and thus gives a digital readout.
Composition of GCF:
The components of the GCF are usually a result of the interaction that occurs between the bacterial biofilm (adherent to the tooth surfaces) and the cells of the periodontal tissues. GCF is basically composed of serum and materials that are generated locally, like products of tissue breakdown, inflammatory mediators and antibodies that are generated against the bacteria in dental plaque. Majority of elements detected so far in GCF have been enzymes, but there are non-enzymatic substances as well. Various components of GCF are,
Components of GCF
|Cellular components||Organic ions||Inorganic ions||Enzymes||Bacterial products|
|Polymorphonuclear leukocytes (neutrophils).||Proteins 70 g/l||Sodium||Acid phosphatase||Endotoxins|
|Lymphocytes.||Albomins 35 g/l||Potassium||Alkaline phosphatase||Trypsin like enzymes|
|Monocytes.||Gammaglobulin 7.5 g/l.||Calcium||Cathepsin B, D||Acid phosphatase|
|Epithelial cells (shedded/desquamation).||Immunoglobins.||Magnesium||Collagenase||Alkaline phosphatase|
|Phosphate||Elastase||Prostaglandin like products|
- Cellular elements: Cellular elements of GCF include bacteria, desquamated epithelial cells and leukocytes.
- Electrolytes: Potassium, sodium and calcium have also been detected in GCF.
Electrolyte ions in Gingival crevicular fluid
|Electrolyte ion||Concentration (mmol/lit)|
|Sodium||91.6 + 31.1|
|Potassium||17.4 + 11.7|
|Calcium||5.0 + 1.8|
|Magnesium||0.4 + 0.2|
|Phosphate||1.3 + 1.0|
- Organic compounds: Carbohydrates, proteins (immunoglobulins, serum albumin), lipids, glucose hexosamine and hexurenic acid. Glucose level of GCF is 3 to 4 times greater than that of serum. Total concentration of protein in GCF is much less than that in serum.
- Metabolic and bacterial products: lactic acid, urea, hydroxyproline, endotoxins, hydrogen sulfide, cytotoxic substances, antibacterial factors.
About 65 components found in GCF have been examined as possible markers for the progression of periodontitis. These components can be generally categorized into following :
- Host-derived enzymes and their inhibitors
- Tissue breakdown products.
- Inflammatory mediators and host-response modifiers
Category 1(Host derived enzymes and their inhibitors) includes:
Factors affecting amount of GCF:
- Mechanical factors: Chewing coarse foods, vigorous brushing and gingival massage are known to enhance GCF production.
- Circadian periodicity: The amount of GCF increases gradually from 6 AM to 10 PM and it decreases after that.
- Sex hormones: Pregnancy, ovulation and contraceptives, increases GCF flow.
- Periodontal surgeries: GCF production increases after periodontal surgeries, during the healing period.
- Smoking: Smoking increases GCF flow. This increase in GCF due to smoking is immediate and transient.
Clinical significance :
- GCF is an inflammatory exudate. The cases when GCF is present in clinically normal gingiva, invariably shows inflammation on microscopic examination. The amount of GCF is sometimes found to be directly proportional to severity of inflammation.
- The measurement of GCF has been used as an index of gingival inflammation. But this can be used only for clinical trials and individual patients. It is not possible for large number of subjects.
- Some drugs are excreted through GCF, for example tetracyclines and metronidazole are excreted through the GCF. This fact is very beneficial in treating periodontal inflammatory conditions.