Aspartate aminotransferase levels in gingival crevicular fluid before and after initial periodontal treatment.

: The present study investigates the presence of the enzyme aspartate aminotransferase (AST) in the gingival crevicular fluid (GCF) of untreated periodontal patients and determines the alterations in enzyme activity after the initial phase of periodontal treatment. From 12 patients suffering from advanced periodontitis, 54 pockets exhibiting severe attachment loss and depth > 4 mm were selected. Measurements of pocket depth (PD), attachment level (AL) and bleeding upon probing (BOP) were undertaken. For the GCF collection, sterile strips were gently placed at the previously isolated gingival crevice for 30 seconds and afterwards the GCF volume was determined with a Periotron 6000. The AST measurements were based on the establishment absorbency coefficient of NADH. The rate of decrease in the concentration of NADH is directly proportional to the AST activity in the sample. Four weeks after completion of the initial treatment, the patients were re-examined and the same clinical and laboratory measurements were performed. The parameters obtained were statistically analysed. The clinical parameters showed a statistically significant improvement, while the laboratory data expressed a statistically significant decrease of GCF volume as expected. Further, the sites were divided in two groups--pathological (pi) and physiological (phi)--according to Persson and Page (1991). After treatment a marked improvement concerning these values was noticed and it was noteworthy that these alterations occured regardless of initial AST presence.