Beta-glucuronidase activity in saliva: relationship to clinical periodontal parameters

BACKGROUND: Beta-glucuronidase (betaG) in gingival crevicular fluid (GCF), a marker of neutrophil influx into the crevicular environment, has previously been shown to be correlated with periodontal clinical parameters at individual sites (probing depth and clinical attachment level). Furthermore, elevated levels of betaG were found to be a risk factor for periodontal attachment loss. Analysis of betaG in saliva may be a measure of crevicular neutrophil influx for the whole mouth. The purpose of this cross-sectional study was to evaluate the relationship between betaG activity in saliva and periodontal clinical parameters in subjects demonstrating various levels of periodontal disease. METHODS: The study population consisted of 380 subjects (108 males and 272 females). A sample of unstimulated whole saliva and a venous blood sample were obtained from each subject, and a periodontal examination, which included measurement of probing depth (PD), attachment level (AL), and gingival index (GI) was performed. The unmodified saliva samples were frozen at -20 degrees C and analyzed for betaG activity. The blood samples were analyzed for number of white blood cells, neutrophils, monocytes, lymphocytes, and platelets. Statistical analysis was conducted to determine the association between salivary betaG activity and the whole-mouth clinical periodontal parameters, complete blood count, smoking status, and age. RESULTS: Highly significant correlations between salivary betaG activity and mean probing depth (MPD), mean gingival index (MGI), and the number of sites with probing depth > or = 5 mm were found. When subjects were divided into tertiles based on their MPD and MGI, elevated salivary betaG activity was detected in subjects in the 2 upper tertiles. Logistic regression modeling was used to determine which of the clinical or laboratory parameters were able to identify patients with at least 4 sites with PD > or = 5 mm. Salivary betaG activity > or = 100 produced an odds ratio (OR) of 3.77. In comparison, current and former smokers had an OR of 3.15 and 2.29, respectively. CONLCUSIONS: The results suggest that a significant association exists between periodontal clinical parameters and salivary betaG activity. Due to the non-invasive and simple nature of saliva collection, this association should be studied to determine its usefulness as a screening test for periodontitis, and a means of monitoring the response to treatment.