Gas-liquid chromatography of the gingival fluid as an aid in periodontal diagnosis

There is increasing evidence that rod-shaped Gram negative anaerobic bacteria, as those belonging to black-pigmented Bacteroides, may play a role in the pathogenesis of periodontal diseases. Anaerobic bacteria are known to produce, as end-products of their metabolism, several volatile fatty acids, whose detection in clinical specimens by direct gas liquid chromatography (GLC) has been usefully utilized to demonstrate their presence in the infected site. The results obtained analyzing by GLC the gingival fluid collected from patients suffering from periodontal diseases are reported here. A good statistical correlation of the GLC profile has been found with the gingival index and the colonization by gram-negative bacteria at each selected site. The data obtained strongly suggest that butyric acid may be considered a reliable marker of the severity of the disease, and its quantitative changes may be useful in following the clinical course of the process. The data correlate well with the biological activities of butyric acid, which have been reported to be abundant in plaque and to exert a cytotoxic activity on a variety of cells including gingival fibroblasts. No correlation has been found between gingival fluid flow rate and fatty acids profile in GLC. It can be concluded that GLC measures the overall metabolic activity of the bacterial population colonizing the subgingival area, while the rate of gingival fluid flow reflects the degree of the inflammatory response of the host. The combined use of the two laboratory tests should provide the clinician with more quantitative and reproducible parameters for monitoring the disease activity.